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Article

Anti-Gnawing, Thermo-Mechanical and Rheological Properties of Polyvinyl Chloride: Effect of Capsicum Oleoresin and Denatonium Benzoate

by
Laongdaw Techawinyutham
1,2,
Arnuparb Prasarnsri
2,3,
Suchart Siengchin
2,3,
Rapeephun Dangtungee
4 and
Sanjay Mavinkere Rangappa
2,3,*
1
Department of Production Engineering, Faculty of Engineering, King Mongkut’s University of Technology North Bangkok, 1518 Pracharat 1 Road, Bangsue, Bangkok 10800, Thailand
2
Natural Composite Research Group, King Mongkut’s University of Technology North Bangkok (KMUTNB), 1518 Pracharat 1 Road, Bangsue, Bangkok 10800, Thailand
3
Department of Materials and Production Engineering, The Sirindhorn International Thai-German Graduate School of Engineering (TGGS), King Mongkut’s University of Technology North Bangkok (KMUTNB), 1518 Pracharat 1 Road, Bangsue, Bangkok 10800, Thailand
4
Maejo University International Collage (MJU-IC), Maejo University, 63 Moo 4 Nongharn Sub District, Sansai District, Chiang Mai 50290, Thailand
*
Author to whom correspondence should be addressed.
J. Compos. Sci. 2022, 6(1), 8; https://doi.org/10.3390/jcs6010008
Submission received: 2 December 2021 / Revised: 18 December 2021 / Accepted: 20 December 2021 / Published: 27 December 2021
Browse Figures
Versions Notes

Abstract

:
Anti-rodent polymer composites were prepared using non-toxic substances denatonium benzoate (DB) and capsicum oleroresin (CO) mixed with polyvinyl chloride (PVC) matrix. DB is mixed in zinc stearate (ZnSt) called DB/ZnSt, and CO, providing burning sensation, is impregnated in mesoporous silica named SiCO. There are three sets of sample: Blank, composites Set I and Set II. Set I consists of DB/ZnSt at concentration of 1.96 wt% and SiCO at concentration of 12.16 wt%, 14.47 wt%, 18.75 wt% and 23.53 wt%. Set II comprises SiCO at the same amount of Set I. The anti-rodent composites studied are anti-gnawing, surface morphology, thermo-mechanical and rheological properties. Anti-rodent testing is analyzed by one-way blocked analysis of variance (ANOVA) and compared with Tukey test with a 95% level of significance, presenting good anti-gnawing efficiency. The best rat-proof sample is II.4, consisting of SiCO 23.53 wt%, which presents percentage of weight loss from gnawing at 1.68% compared to weight loss of neat PVC at 59.74%. The addition of SiCO at concentration ranging from 12.16 to 23.53 wt% reduces tensile strength around 25–50%, elongation at break strength around 2–23%, shear storage modulus (G′) around 30%, shear loss modulus (G″) shear viscosity (η) and glass transition (Tg) around 43% compared to Blank. The increase in SiCO concentration slightly improves the thermal stability of PVC composites around 3%, but the addition of DB/ZnSt at 1.96 wt% slightly reduces those properties.

1. Introduction

The damage of plastic products, especially electrical wire and cable, is often caused by rodents. This may cause outages or short circuits and fires and can stop production lines and break expensive machines [1,2]. Rodents prefer to gnaw elastomeric materials, especially flexible PVC, which is the main plastic for making insulation of electrical wire and cable [3]. They gnaw because all rodents have a single pair of incisors in the top and bottom jaws that are rootless and grow continuously throughout their lives [4,5]. If they allow their incisors to grow without restraint, they would not be able to gnaw their food and then would subsequently die. Therefore, they spend their lives gnawing and wearing their teeth down [6].
Today, methods for repelling rodents use chemical substances (rodenticides bait, rat poisons) [7,8], natural substances (peppermint oil, bay leaf, onions and chili) [9,10] and electronic control (e.g., ultrasonic, radio wave) [11,12], some of which can bring harm to humans, pets and the environment. This research uses non-lethal methods to prevent or deter rodent chewing on plastic products. The non-toxic chemical substances mixed in the PVC (polyvinyl chloride) compound are denatonium benzoate (DB) and capsicum oleoresin (CO). DB and CO provide an intensely bitter taste and burning sensation, respectively, resulting in a behavioral change of the rodents to stop chewing the plastic product. DB is the bitterest chemical compound known, it is also non-toxic, odorless, colorless and non-reactive [13,14,15]. It can be detected by humans at a concentration of 10 ppb, is discernibly bitter at 50 ppb and is unpleasantly bitter at 10 ppm [16,17]. CO is a dark reddish–brown liquid concentrate used as the alternative natural substance of capsaicin (CS), which is the main substance giving spicy taste and burning sensation for mammals in chili, because the cost of CS limits its usage [18,19,20]. The main component of CO is CS [21]. One ppm of CS provokes a perceptible warm sensation on the human tongue, and 10 ppm provokes a persistent burning sensation on the tongue [22].
There are many works using CS and DB in plastic products for repelling rodents. Zhu [23] invented a rat-proof plastic drip irrigation tube/belt using synthetic CS as a rat-proof substance. The rat-proof tube/belt is non-toxic, does not pollute the environment and provides excellent anti-chewing deterrent against rodents. We et al. [24] invented anti-mouse cable and wire consisting of modified CS. CS covered acrylate for slow release, having a long-term repellent effect. Shumake et al. [25] studied the reduction of cable gnawing by northern pocket gophers by coated anti-gnawing substances on the cable. The repellent treatments consisted of 2.0% mass/mass levels of CS and DB. CS and DB appeared to be absolutely effective substances applied as a surface coating to cable to control gnawing damage by northern pocket gophers. Ichino [26] invented flexible PVC with DB against gnawing from rodents. DB acts as a repellent substance that at 2.5 wt% represents a practical maximum amount in PVC matrix. The rat-proof flexible PVC provided good effectiveness on the plastic. Techawinyutham et al. [27] studied SiCO/polylactic acid (PLA) composites, and results showed that the incorporation of SiCO (0.77, 1.54 and 3.08 wt%) slightly improved tensile strength but did not significantly affect tensile modulus and elongation.
The aim of this study is to create anti-rodent polymer composites and examine influence of anti-gnawing substances by means of the structure–property relationships such as rheological, mechanical and thermal properties. The concentration of anti-gnawing substances, SiCO and DB/ZnSt, was examined by the work of Techawinyutham et al. [28] with an anti-gnawing test of two weeks. This study focuses on the efficiency of anti-rodent substances (DB/ZnSt and SiCO) for three months in terms of percentage of weight loss using one-way ANOVA with block design analysis with a 95% level of significance of data. If the combination of DB/ZnSt and SiCO in PVC shows less gnawing damage than neat PVC, the composites can prevent rodents from severely damaging the essential plastic product made from flexible PVC such as electrical wire and cable.

2. Materials and Methods

2.1. Materials

The CO was extracted from hot chili powder (Aro from Siam Makro Pub Co., Ltd., Bangkok, Thailand). Silica (CAS 112926-00-8) was in crystal form (22S Sipernat®, Evonik company, Essen, Germany). The particle size and surface area of silica were 14 µm and 180 m2/g, respectively. DB (CAS 3734-33-6) in white crystalline pellets was purchased from Gratitude Infinite Pub Co., Ltd., Bangkok, Thailand. ZnSt (CAS 557-05-1) (Z784, Fisher Scientific International, Inc., Hampton, NH, USA) in white powder solid with melting temperature (Tm) of 118–128 °C acted as a coating for anti-accumulation of DB, improving the distribution of DB in PVC matrix. PVC compound granulate (C2904NTA grade, Thai Plastic and Chemicals Pub co., Ltd., Rayong, Thailand) was selected as a polymer matrix for the entire composites with a specific gravity of 1.38 g/cm3 (ASTM D792), elongation 279% and tensile strength of 17.3 MPa (JIS 3342).

2.2. Sample Preparation

2.2.1. CO Extraction

Dark reddish-brown liquid CO in Figure 1a was extracted from chili powder with a volatile solvent. Chili powder was soaked in acetone (chili powder: acetone = 5 g: 18 mL), then stirred at 1300 rpm for 7 h by an overhead stirrer (RW20 digital IKA Company, Freiburg im Breisgau, Germany). The mixture of CO was filtered by filter paper with 125 mm of diameter (Whatman™, Maidstone, UK).

2.2.2. SiCO Preparation

Transformation of CO liquid to solid powder by using impregnation method is CO absorbed in the porous silica (SiCO) at a concentration of CO of 65 wt% and silica of 35 wt% as shown in Figure 1b. Firstly, silica was mixed with acetone then stirred at 50 °C for 5 min (RW20 digital IKA Company). Secondly, the CO was added to silica solution and stirred for 10 min. Finally, the SiCO was dried in an oven (Redline Model RF115 by Binder, Camarillo, CA, USA) at 60 °C for 2 h.

2.2.3. DB/ZnSt Preparation

The small concentration of DB in the polymer matrix and large particle size of DB may lead to poor distribution and dispersion. Thus the process for reducing the size of DB and improving distribution and dispersing was needed. ZnSt was mixed with DB for anti-accumulation since the hydrophobic ZnSt particles covered the DB surface. The first procedure was mixing DB and ZnSt at weight ratio 1:1 in the high-speed mixer with agitator rotated at 3000 rpm and vibration of the chamber at 30 Hz for 5 min. The second process was decreasing particle size of DB/ZnSt using four hammer mills at high speed of 7000 rpm for 2 min, as presented in Figure 1c, with particle size of 3.49 ± 1.27 µm.

2.2.4. Anti-Rodent Sample Preparation

PVC compound pellets and anti-gnawing substances were subsequently mixed in an internal mixer (MX75, Chareon Tut co., Ltd., Samut Prakan, Thailand) at various contents following Table 1 at a rotational speed of 40 rpm at 160 °C for 10 min. The concentration of anti-gnawing substances, SiCO and DB/ZnSt, combined with PVC matrix determined by work of L. Techawinyutham et al. [28]. The anti-rodent composites were subsequently compressed by compression molding machine (QC-601T, Comtech company, Taipei, Taiwan) at 170 °C, with preheat and a compression process time of 10 min at a pressure of 2500 psi. Then, the samples were cut for anti-gnawing, morphology, thermo-mechanical and rheological test.

2.3. Experimental Design and Anti-Gnawing Test Procedures

In the anti-gnawing study, female rats (Rattus norvegicus, Wistar, 6 wk) were used since they are less aggressive and more commonly housed in a group and for a longer period than male rats [29,30]. However, there was no scientific report about the gender effect on gnawing behavior. There were two rats in cage 1 and cage 2. For cage 3, there was a rat as displayed in Figure 2. The samples can be divided into 3 sets; Blank, Set I and Set II. The sample shape was rectangular (15 mm × 100 mm × 2.8 mm) and made a small hole at the top of the samples for hanging in the cage as shown in Figure 3. Each set of samples were hung on the lid of the cage for a month, after that the samples will be subsequently replaced with the new set of samples as shown in Table 2. The weight of the samples and the appearance was recorded at the end of each month. There were 8 pieces of Blank and 2 pieces of each concentration for composite Set I and Set II.

Statistical Analysis

The obtained data in term of percentage of weight loss of the samples were analyzed using one-way blocked analysis of variance (ANOVA) and means were compared with Tukey test by Minitab Statistical Software 17 (Minitab Inc., State College, PA, USA) with a 95% level of significance. ANOVA can help to present the influence of anti-rodent substance concentration, number of rats and period of time on the percentage of weight loss; therefore, the optimum concentration of the substances can be predicted.

2.4. Fourier-Transform Infrared Spectroscopy (FT-IR)

PVC compound and the PVC composites were loaded in FT-IR spectroscopy in attenuated total reflection (ATR) accessory for reflection mode using a Thermo Scientific Nicolet 6700 FT-IR spectrometer (Thermo Fisher Scientific Inc.) with a scan range from 400 to 4000 cm−1.

2.5. Morphology

The scanning electron microscope (SEM) micrographs backscattered electron (BSE) mode of the surface structure of PVC and PVC composites were obtained by using a low-vacuum operated at 20 kV at a magnification of 250× (non-sputter coated). The samples were laid on a graphite conductive coating film. The SEM and energy dispersive spectroscopy (EDS) results were obtained from SEM instrument, a Hitachi, model SU3500 (Japan). For high magnification at 1000x of surface morphology of PVC, I.4, and II.4, the samples were coated with a platinum layer in argon gas at a power of 10 mA for 1 min using an MC1000 ion sputter coater machine (Hitachi, Tokyo, Japan) SEM sputter coater before taking the SEM image.

2.6. Tensile Response

Tensile test was determined on the universal testing machine (Cometech QC-506M1-204, Taichung City, Taiwan) according to ASTM D638. The tensile test was performed at room temperature with crosshead speed of 50 mm/min and gauge length of 25 mm. The dimension of the specimens followed ASTM D638 IV with a thickness of 3 mm. At least five experiments were performed for each sample and the average values were considered and discussed.

2.7. Thermal Properties Analysis

2.7.1. Differential Scanning Calorimetry (DSC)

DSC measurements (DSC 3—Mettler Toledo CO. Ltd., Greifensee, Switzerland) were carried out to analyze the thermal properties of Blank and PVC composites. A small piece of samples (5.0 ± 1 mg) were scanned in the range of −65–180 °C at a heating rate and cooling rate of 20 °C/min with the isothermal period for 2 min. N2 environment at a constant flow rate of 50 mL/min was used. Thermal enthalpy of the samples was characterized by glass transition temperature (Tg).

2.7.2. Thermogravimetric Analysis (TGA)

Thermogravimetric Analysis (TGA) TGA instrument was Mettler Toledo TGA/DSC 3+ HT/1600 with identification 360 and the main sensor (TGA/HT DSC HSS2). The sample weight of PVC and all composites was 16 ± 2 mg. The testing temperature range was 40–600 °C with isothermal for 3 min at 40 °C. The testing occurred under a nitrogen atmosphere with a constant flow rate of 50 mL/min at a constant heating rate of 10 °C/min for investigating degradation temperature and thermal stability of PVC and all PVC composites.

2.8. Dynamic Rheology

The rheological properties of the molten Blank and the PVC composites were analyzed using a rheometer (KNX2112, Malvern, UK) with parallel plates geometry with a diameter of 25 mm. The specimens were cut into a circle shape with a diameter of 25 mm and thickness of 3 mm. The measurements were performed in the dynamic oscillatory mode at 170 °C. The strain value was set at 0.1% to linear viscoelastic region (LVR) of PVC. The shear modulus of each sample was measured under frequency sweep which was taken in range from 0.1 to 1000 Hz with a constant strain at 0.1% with preheating time for 5 min. Shear viscosity (η) of Blank and PVC composites was investigated under dynamic strain sweep (0.01–500%) at 170 °C with preheating time for 5 min.

2.9. Accelerated Weathering

Accelerated weathering is a weathering testing to measure future properties of materials under adverse environmental conditions (ultraviolet radiation, extreme temperature, and humidity conditions). PVC, I.4 and II.4 were aged according to ASTM G155-13 cycle 1 in accelerated weathering tester machine (Q-Sun Xe-3, Q-Lab Corp., Westlake, PA, USA). One side of those samples was exposed to artificial light of xenon lamp with irradiance of 0.35 W/m2 and UV sensor of 340 nm at a temperature of 63 °C for 102 min in the controlled humidity of 30% in an accelerated weathering chamber. For the second step, the samples were exposed to light irradiation and water spray with irradiance of 0.35 W/m2 and UV sensor of 340 nm for 18 min. The samples were removed at 300 h and 600 h from accelerated weathering chamber.

3. Results and Discussion

3.1. Characterization

3.1.1. Morphology Response of DB/ZnSt

SEM micrographs at 100× magnifications and EDS mapping of DB/ZnSt particles are displayed in Figure 4a,b respectively. SEM image of DB/ZnSt particles was scanned for identifying chemical composition mapping by EDS technique. EDS mapping used for ensuring that DB was covered with ZnSt particles. It showed that DB was mixed in ZnSt homogeneously and DB also was covered with ZnSt particle for preventing agglomeration of DB and improving dispersion of DB in PVC matrix.

3.1.2. Morphology Response of PVC and PVC Composites

SEM micrographs at 100× magnifications of PVC compound and PVC composite surface are presented in Figure 5 (Also Refer: Figure S1). The fillers showed good distribution in PVC matrix. The increase in anti-gnawing substances (SiCO and DB/ZnSt) caused the holes on the sample surface to be larger, due to high substance particles causing weak interaction between the PVC matrix and the substances.
Comparing PVC composites Set I and Set II, EDS mapping showed that PVC composites Set I had greater and bigger holes than PVC composites set II. It may be DB/ZnSt had poor adhesion with PVC as shown in Figure 5b–i. The surface of PVC composite samples had higher and larger holes compared to PVC because of the existence of SiCO and DB/ZnSt. From Figure 6, the surface roughness of composite Set I (consisting of DB/ZnSt) was higher than composite Set II because anti-gnawing substances reduced the adhesion between the fillers and PVC matrix, especially DB/ZnSt due to good lubricating property of ZnSt and oily property of CO.

3.1.3. Fourier-Transform Infrared Spectroscopy (FTIR)

FTIR-ATR was used to investigate the difference in structure of PVC and PVC composites as shown in Figure 7. The band of PVC was described in Table 3. FTIR spectrums of PVC composites were slightly different from Blank because of overlapping bands of PVC, DB and SiCO [31]. FT-IR bands of I.4 consisted of phenylic residues as 1536 cm−1 referring to DB and Si–O–Si bonding as 1103 cm−1 and 472 cm–1 referring to silica (SiCO) [32,33,34,35]. Band of II.4 also showed Si–O–Si bonding at bands of 1103 and 472 cm–1 referring to silica. Additionally, other peaks of SiCO and peak of DB was overlapped by peaks of PVC compound. The bands of carbonyl group and Si–O–Si bonding were slightly shifted to higher wavenumber probably because of an increase in those group structures due to addition in SiCO.
The degradation of chemical structures of PVC and PVC composites after aging in weathering machine were analyzed by ATR-FTIR in Figure 7. Comparing FT-IR curve of non-aging sample and aging sample, it can be clearly seen the change of spectra. The longer weathering time decreased intensities of the distinctive IR bands of Blank, I.4 and II.4 as similar to work of Matuana et al. [41] Gallouze et al. [42]. Moreover, it can be observed that the shift of FTIR spectrum to lower wavenumber referred to a decrease in that bonding as degradation of those structures. It was because the significant levels of chemical degradation action of “photolysis” and “hydrolysis“ caused random main chain scission [42,43,44,45]. It also shifted bands of the ester carbonyl group C=O (1716–1724 cm−1) to lower wavenumber [45].
PVC degradation firstly induced the oxidation of these polyenes providing conjugated double bonds and the carbonyl groups [46]. The decrease in absorption band means that the PVC chains were maybe cut and the atoms decreased especially in polyene and the carbonyl groups by water, temperature and UV irradiation during weathering test [47]. The concentration of SiCO and DB also decreased with increasing aging time; moreover, the anti-rodent substances seemed to increase the degradation of PVC structures. It is likely because the large difference in swelling and shrinkage between the fillers and PVC matrix from moisture and high temperature during aging leading to cracking and stress formation at the particle/matrix interface [48,49]. From FTIR result, it can be suggested that the PVC composites are suitable to be used at aging time lower than 620 h.

3.2. Anti-Rodent Testing

ANOVA was used to evaluate the significance of concentration of substances, number of rats and period of testing time on anti-rodent test in term of percentage of weight loss. The result showed that model summary of one-way blocked ANOVA provided a coefficient of determination (R-squared) 80.53% and the probability of residual plot at p value > 0.235 as shown in Figure S2. The analysis of variance for the percentage of weight loss was presented in Table 4.
The results showed that the most gnawed sample was Blank. The minimum average of weight loss occurred at II.4. Tukey pairwise comparisons of samples, cage and period of time on sample weight loss with 95% confidence showed in Table 5, Table 6 and Table 7 respectively. It is reported that Blank cannot prevent rodent, but the best rat-proof sample was II.4 which showed mean of weight loss at 1.68%. The other samples were not different significantly on the anti-gnawing test. From Figure 8, it can be clearly seen that the increase in SiCO concentration caused reduction in the sample weight loss. Table 5 shows that there was no significant difference in weight loss in the Set I because of the existence of DB/ZnSt giving bitter taste. The percentage of weight loss of II.4 is slightly lower than I.4. It may be some degradation of low thermal stability DB. From the results, it can be concluded that SiCO and DB can protect the polymer from gnawing by rodent.
The influence of the number of rats on weight loss was investigated. Cage 3 (individual rat) showed the highest weight loss since individual rat had more aggressive behavior and/or stress than social rat. The social rat had relations with their members [29,50]. This led the individual rat to bite something for stress relaxation, because gnawing behavior of rat comes from stress or loneliness [51,52,53,54]. Table 6 presents cage 1 and 2 consisting of two rats that were not significantly different.
The period of time for anti-gnawing testing affected the percentage of weight loss. Table 7 shows that weight loss at the first month and the last month was clearly different. The weight loss of the 1st month showed the maximum value at around 26%, since at the beginning of the test, the rats were excited with the samples; however, after that they felt less interested. Therefore, the minimum weight loss was shown at the last month in the sample.

3.3. Tensile Properties

Tensile test was used for determining tensile strength, tensile modulus and elongation at break of Blank and all PVC composites as presented in Table 8 and Figure 9. The addition of anti-gnawing substances: SiCO and DB/ZnSt obviously decreased in tensile strength of the composites compared to Blank. Tensile strength of the composites Set I did not differ significantly to composites Set II since small amount of DB/ZnSt did not have an effect on tensile strength. It can be concluded that only SiCO had an influence on tensile strength. The tensile strength reduced with increasing content of SiCO in the PVC matrix especially for I.3, I.4, II.3 and II.4. It is because the high concentration of stresses around the filler particles and the aggregation of SiCO particles in PVC matrix contributed to decrease in the contact area between PVC and SiCO as well as created physical defect in the PVC composites, as can be clearly seen in SEM micrographs displaying voids on the sample surface [55,56]. It caused no stress transferred from PVC matrix to the particles [55,56,57]. Similarly, A. Zhu et al. [57] found that tensile strength decreased with addition content of silica in PVC up to 4 wt% and J. E. Crespo et al. [55] reported that an increase in filler content in PVC led to tensile strength decrease. Moreover, capsicum oil acting as plasticizer in the PVC matrix reduced tensile strength as similar to work of N. Gil et al. [58] since the polymer chains can move freely with high mobility [55,59].
Elongation at break of Blank did not differ significantly to PVC composites except I.4 and II.4 because of high amount of SiCO. Normally, silica decreased elongation at break but the addition of SiCO in PVC matrix below 18.75 wt% did not reduce the elongation, due to capsicum oil improving chain mobility of PVC [55,59]. The elongation was not affected by DB/ZnSt. The addition of SiCO at 23.53 wt% (I.4 and II.4) resulted in a reduction of elongation at break due to high concentration of silica causing weak interaction between fillers and polymer matrix. The addition content of silica in PVC matrix decreased in elongation similar to work of Ł. Klapiszewski et al. [60] because poor stress transferred from PVC matrix to fillers [55,56,57,58].
The addition of anti-rodent substances caused slight decrease in tensile modulus compared to Blank. The small amount of DB/ZnSt in PVC matrix did not reduce tensile modulus. The capsicum oil in SiCO had a negative effect on the rigidity of PVC which led to the modulus being decreased with increasing plasticizer content as similar behavior to work of Crespo et al. [55] and Gil et al. [58]; however, the increase in SiCO concentration in this work did not affect the modulus. This may be because of the higher amount of silica improving tensile modulus and the resistance to deformation of the composites. This was similar to work of Ł. Klapiszewski et al. [60] and M. Fasihi et al. [61] because of strong stiffness of silica particles. It can be summarized that SiCO had a minimal effect on reducing tensile modulus.

3.4. Thermal Analysis

3.4.1. Differential Scanning Calorimetry (DSC)

The influence of anti-gnawing substance in PVC matrix on thermal properties was investigated by DSC. The 2nd heating curve is displayed in Figure 10. The 2nd heating curve of Blank and PVC composites did not clearly show crystallization temperature (Tc) and melting temperature (Tm), similar to work of Jia et al. [62]. Tg of the PVC composites was slightly lower than PVC because of SiCO. The increase in SiCO concentration dropped Tg of PVC composites since capsicum oil acted as plasticizer [63]. The shifting of Tg to lower temperature because of CO acting as plasticizer was similar to work of C. Bueno-Ferrer [64] and P. G. Nihul [65]. CO corresponds to increase in disorder, free volume of the macromolecules and chain mobility of PVC [62]. It was also probably because agglomeration of SiCO particles dropped the interaction between PVC chains and the fillers [66]. However, work of M. Mohagheghian [67] and S. Lavina [68] reported that the additional amount of silica particles in PVC matrix increased in Tg of the composites and reduction in chain the mobility of polymer [67]. It can be concluded that CO had higher influence on Tg than silica. DB in composite Set I provided higher Tg than composite Set II since some degradation of DB in the PVC matrix obstructed the movement of PVC chain [67]. The small endothermic peak occurring in Blank around 110 °C and in the composites ranging from 75 to 85 °C was a change in heat capacity probably due to degradation of the additive in the flexible PVC [69]. At low thermal decomposition, the addition of capsicum oil in SiCO slightly decreased thermal stability of the composites.

3.4.2. Thermogravimetric Analysis (TGA)

Thermal stability of PVC and all composites were analyzed by TGA and DTG presented in Figure 11 and Figure 12 respectively. All TG curves indicated two major steps of weight loss which displayed similar degradation trend as similar work of Al-Sagheer et al. [16], Klapiszewski et al. [60] and Ari et al. [70] The first step of weight loss occurring in the temperature ranging in 250–350 °C as presented in Table 9 was attributed to the PVC dehydrochlorination process corresponding to the HCl elimination reaction followed by the formation of conjugated structure polyene sequences or the polyene linkages [16,60,70,71]. The second step of weight loss, occurring in a higher temperature in range of 350–500 °C, corresponds to thermal degradation of carbon chain of conjugated structure polyene [16,70]. The thermal degradation of the composites Set I shifted to lower temperature; however, for the composites Set II the thermal degradation shifted to higher temperature compared to PVC compound. This is because the composites Set I consisted of low thermal stability of DB/ZnSt that initiated the dehydrochlorination of PVC. For the PVC composites, the increase in content of SiCO led to improving of thermal degradation of PVC because of high thermal stability of silica particles. Silica can improve thermal stability of PVC as similar to work of Mohagheghian et al. [67] and Al-Sagheer and Z. Ahmad [16] since the polymer chains were restricted and absorbed in the thermally stable silica network. Moreover, silica required higher heat to be decomposed into ash than the polymer matrix [67]. Mohammad et al. [58] reported that plasticizer in PVC accelerated the degradation of PVC; however, in this work, CO absorbed in nanoporous silica did not decrease thermal stability of PVC matrix. Greater content of SiCO increased residual weight due to the residual of silica retained [16]. The residual weight of the PVC composites Set I higher than PVC and composite Set II due to char of DB. It can be concluded that DB/ZnSt produced poor effect on thermal stability of PVC; however, the addition of SiCO particles in PVC matrix improved thermal stability of the PVC.

3.5. Rheological Behavior

The dynamic rheological behavior of Blank and all composites were determined by oscillary rheometer. G and Gʺ as a function of frequency for PVC and the PVC composites plotted on log-log scale compound are shown in Figure 13a,b respectively. G′ of PVC and PVC composites was lower than G″. The highest shear storage modulus was PVC for all frequencies. The addition in SiCO led to increasing in G′ and G″ at low frequency. For the composites Set I consisting of DB/ZnSt caused G′ and G″ slightly lower than composites Set II because ZnSt acting as plasticizer improved chain mobility reduced G′ and G″ of the composites [72]. This was similar to research of Liang et al. [72] and Sugimoto et al. [73]; moreover, they reported that Gʹ reduced with increasing plasticizer concentration. The increase in the amount of SiCO improved G′ and G″ as similar behavior to work by Al-Oweini et al. [33] and Kamibayashi et al. [74] since silica particle obstructed polymer chain mobility [70]. Although silica improved G′ and G″ of PVC matrix, there was CO in porous of silica acting as a plasticizer. It caused G′ and G″ of the PVC composites lower than those of PVC.
The shear viscosity as a function of shear rate of Blank and all PVC composites are displayed in Figure 14. PVC showed the highest shear viscosity. The PVC composites Set II had higher shear viscosity than Set I since ZnSt in DB/ZnSt in composites Set I acts as a lubricant. The melt viscosity of all PVC composites and PVC did not observe a Newtonian plateau viscosity; however, they exhibited shear thinning profile at all shear rates. The higher shear rate, the more shear-thinning behavior. The increase in SiCO concentration reduced shear viscosity because capsicum oil acted as plasticizer and improved chain mobility of PVC since it decreased polymer concentration in the continuous phase [72]. The addition of silica concentration increased shear viscosity since the high surface area of silica particles improved interaction between PVC and silica which led to restricting polymer chain mobility [70]. However, the viscosity of the composites did not improve as regularly as was found in the work of Kamibayashi et al. [74] and Otsubo [75]. CO had a higher influence on shear viscosity than silica. It can be concluded that the shear viscosity of the PVC matrix decreased with increasing SiCO concentration.

4. Conclusions

The influence of DB/ZnSt and SiCO composited with PVC on anti-gnawing, morphology, thermo-mechanical and rheological properties were studied. Anti-rodent substances were a good distribution in PVC matrix; however, the addition in substances increased the hole on the PVC surface and reduced interaction between the fillers and PVC matrix. Anti-gnawing data were analyzed by one-way block design of ANOVA. The statistical model shows that it fits a set of observations. SiCO and DB/ZnSt can protect the polymer from the rodent. The results suggested that II.4 consisting of SiCO at 23.53 wt% was the best anti-rodent composite with good mechanical and thermal properties. The addition of SiCO and DB/ZnSt decreased tensile strength. For the highest SiCO concentration, elongation at break reduced since a high amount of SiCO decreased compatibility between PVC matrix and the substances. However, the tensile modulus did not change significantly with an increasing amount of SiCO. Tg, G′, G″ and η decreased with increasing SiCO concentration since capsicum oil improves the flexibility of PVC. Thermal stability of PVC reduced with addition DB, but it improved with an increasing amount of SiCO.

Supplementary Materials

The following are available online at https://www.mdpi.com/article/10.3390/jcs6010008/s1, Figure S1: EDS mapping micrographs, Figure S2: Probability plot of percentage of weight loss, Figure S3: Samples after anti-gnawing test for one month, Figure S4: DSC cooling curve of PVC compound and PVC composites.

Author Contributions

Conceptualization, R.D. and L.T.; methodology, L.T. and A.P.; formal analysis, investigation, writing—original draft preparation, L.T.; writing—review and editing, S.M.R.; visualization, supervision, S.S. and R.D. All authors have read and agreed to the published version of the manuscript.

Funding

This research was funded by King Mongkut’s University of Technology North Bangkok (KMUTNB) with Contract no KMUTNB-65-BASIC-01.

Institutional Review Board Statement

The study was conducted according to the guidelines of the Declaration of Helsinki, and approved by the Institutional Review Board (or Ethics Committee) of Mahidol University (protocol code of MUSC59-011-344 and date of approval of 21 December 2016).

Acknowledgments

The author gratefully thanks Natural Composites Research Lab (NCR) (Materials and Production Engineering, KMUTNB) for financial and instrument, Center of Innovation in Design and Engineering for Manufacturing (CoI-DEM), KMUTNB for supporting TGA machine and World Pigment Industries Co.,Ltd. (Bangkok, Thailand) for supporting silica and ZnSt. We would like to thank COAX Group Corporation Ltd., Bangkok, Thailand for supporting SEM machine and EDS analytical system and Tepmanas Bupha-Intr for helping anti-gnawing testing. Protocal no. MUSC59-011-344 is approved from Faculty of Science, Mahidol University.

Conflicts of Interest

The authors declare no conflict of interest.

References

  1. Bin, N.-R.; Song, H.; Wu, C.; Lau, M.; Sugita, S.; Eubanks, J.H.; Zhang, L. Continuous Monitoring via Tethered Electroencephalography of Spontaneous Recurrent Seizures in Mice. Front. Behav. Neurosci. 2017, 11, 1–9. [Google Scholar] [CrossRef] [PubMed] [Green Version]
  2. Folorunso, O.; Emmanuel, O.; France, A. Electrical Arching and Thermal Circuit Breakers: A Review. ABUAD J. Eng. Res. Dev. 2018, 1, 149–155. [Google Scholar]
  3. Heggs, R.P.; Pierce, B.C.; Balbes, L.M.; McRoberts, K.C.; Streicker, M.A.; Cockerline, K.B. Assessing Rodent Gnawing of Elastomers Containing Soybean Oil Derivatives. ACS Sustain. Chem. Eng. 2020, 8, 18015–18022. [Google Scholar] [CrossRef]
  4. Sukseree, S.; Schwarze, U.Y.; Gruber, R.; Gruber, F.; Rey, M.Q.D.; Mancias, J.D.; Bartlett, J.D.; Tschachler, E.; Eckhart, L. ATG7 Is Essential for Secretion of Iron from Ameloblasts and Normal Growth of Murine Incisors during Aging. Autophagy 2020, 16, 1851–1857. [Google Scholar] [CrossRef] [PubMed]
  5. Desoky, A.E.-A.S.S. Genetic Modification Responsible for Continuously Growing Incisors in Rodent. JBGSR 2020, 1. [Google Scholar] [CrossRef]
  6. Martin, L.F.; Winkler, D.; Tütken, T.; Codron, D.; De Cuyper, A.; Hatt, J.-M.; Clauss, M. The Way Wear Goes: Phytolith-Based Wear on the Dentine–Enamel System in Guinea Pigs (Cavia Porcellus). Proc. R. Soc. B Biol. Sci. 2019, 286, 1–9. [Google Scholar] [CrossRef] [Green Version]
  7. Walther, B.; Geduhn, A.; Schenke, D.; Schlötelburg, A.; Jacob, J. Baiting Location Affects Anticoagulant Rodenticide Exposure of Non-Target Small Mammals on Farms. Pest Manag. Sci. 2021, 77, 611–619. [Google Scholar] [CrossRef] [PubMed]
  8. Frankova, M.; Stejskal, V.; Aulicky, R. Efficacy of Rodenticide Baits with Decreased Concentrations of Brodifacoum: Validation of the Impact of the New EU Anticoagulant Regulation. Sci. Rep. 2019, 9, 16779. [Google Scholar] [CrossRef] [Green Version]
  9. Hansen, S.C.; Stolter, C.; Jacob, J. Effect of Plant Secondary Metabolites on Feeding Behavior of Microtine and Arvicoline Rodent Species. J. Pest Sci. 2016, 89, 955–963. [Google Scholar] [CrossRef]
  10. Aminkhani, A.; Sharifi, S.; Hosseinzadeh, P. Chemical Constituent, Antimicrobial Activity, and Synergistic Effect of the Stem, Leaf, and Flower Essential Oil of the Artemisiafragrans Willd. from Khoy. Chem. Biodivers. 2021, 18, e2100241. [Google Scholar] [CrossRef] [PubMed]
  11. Saranya, K.; Uva Dharini, P.; Uva Darshni, P.; Monisha, S. IoT Based Pest Controlling System for Smart Agriculture. In Proceedings of the 2019 International Conference on Communication and Electronics Systems (ICCES), Coimbatore, India, 17–19 July 2019; pp. 1548–1552. [Google Scholar] [CrossRef]
  12. Zhelev, G.; Koev, K.; Stoyanov, V.; Petrov, V. Electronic Rat-Control Devices—Solution or Scam? Results of Field Trials and a Summary of the Literary Data. AVM 2018, 11, 27–36. [Google Scholar] [CrossRef]
  13. Holvoet, J.-P. Denatonium Benzoate. Available online: http://www.sentinalco.com/page/denatonium/f1.html (accessed on 29 May 2018).
  14. Material Safety Data Sheet Denatonium Benzoate MSDS. Available online: http://www.sciencelab.com/msds.php?msdsId=9923674 (accessed on 29 May 2018).
  15. Marples, N.M.; Roper, T.J. Response of Domestic Chicks to Methyl Anthranilate Odour. Anim. Behav. 1997, 53, 1263–1270. [Google Scholar] [CrossRef] [Green Version]
  16. Al-Sagheer, F.A.; Ahmad, Z. PVC-Silica Hybrids: Effect of Sol–Gel Conditions on the Morphology of Silica Particles and Thermal Mechanical Properties of the Hybrids. J. Sol-Gel Sci. Technol. 2012, 61, 229–235. [Google Scholar] [CrossRef]
  17. Payne, H.A.S. Bitrex—A Bitter Solution to Safety. Chem. Ind. 1988, 22, 721–723. [Google Scholar]
  18. Barceloux, D.G. Pepper and Capsaicin (Capsicum and Piper Species). Dis. Mon. 2009, 55, 380–390. [Google Scholar] [CrossRef] [PubMed]
  19. Science Lab. Material Safety Data Sheet Oleoresin Capsicum, Natural MSDS, (2013). Available online: https://www.sciencelab.com/msds.php?msdsId=9926319 (accessed on 2 December 2021).
  20. Barceloux, D.G. Medical Toxicology of Natural Substances: Foods, Fungi, Medicinal Herbs, Plants, and Venomous Animals; John Wiley & Sons: Hoboken, NJ, USA, 2012. [Google Scholar]
  21. Wesołowska, A.; Jadczak, D.; Grzeszczuk, M. Chemical Composition of the Pepper Fruit Extracts of Hot Cultivars Capsicum annuum L. Acta Sci. Pol. Hortoru. 2011, 10, 171–184. [Google Scholar]
  22. Nelson, E.K. Capsaicin, The Pungent Principle of Capsicum, and the Detection of Capsicum. J. Ind. Eng. Chem. 1910, 2, 419–421. [Google Scholar] [CrossRef]
  23. Zhu, S. Ratproof Plastic Drip Irrigation Tube/Belt and Preparation Method Thereof, CN102321284 A. 2012. Available online: http://www.google.com/patents/CN102321284A (accessed on 18 March 2016).
  24. Xu, Y.; Mu, X.; Xiao, M.; Zhong, W.; Li, Y.; Wu, J. Mouse-proof cable material containing modified capsaicin and its preparing method, CN1971769 A. 2007. Available online: http://www.google.com/patents/CN1971769A (accessed on 8 December 2017).
  25. Shumake, S.A.; Sterner, R.T.; Gaddis, S.E. Repellents to Reduce Cable Gnawing by Northern Pocket Gophers. J. Wildl. Manag. 1999, 63, 1344. [Google Scholar] [CrossRef] [Green Version]
  26. Ichino, T. Sensorially Active Substance Embedded in Plastic, US6468554 B1. 2002. Available online: http://www.google.com/patents/US6468554 (accessed on 11 April 2016).
  27. Techawinyutham, L.; Siengchin, S.; Dangtungee, R.; Parameswaranpillai, J. Influence of Accelerated Weathering on the Thermo-Mechanical, Antibacterial, and Rheological Properties of Polylactic Acid Incorporated with Porous Silica-Containing Varying Amount of Capsicum Oleoresin. Compos. B Eng. 2019, 175, 107108. [Google Scholar] [CrossRef]
  28. Techawinyutham, L.; Dangtungee, R. Anti-Rodent Polymer Composites. Key Eng. Mater. 2019, 818, 1–6. [Google Scholar] [CrossRef]
  29. Meaney, M.J.; Stewart, J. A Descriptive Study of Social Development in the Rat (Rattus Norvegicus). Anim. Behav. 1981, 29, 34–45. [Google Scholar] [CrossRef]
  30. Hurst, J.L.; Barnard, C.J.; Tolladay, U.; Nevision, C.M.; West, C.D. Housing and Welfare in Laboratory Rats: Effects of Cage Stocking Density and Behavioural Predictors of Welfare. Anim. Behav. 1999, 58, 563–586. [Google Scholar] [CrossRef] [PubMed] [Green Version]
  31. Kaynak, C.; Erdogan, A.R. Mechanical and Thermal Properties of Polylactide/Talc Microcomposites: Before and after Accelerated Weathering. Polym. Adv. Technol. 2016, 27, 812–822. [Google Scholar] [CrossRef]
  32. Brinker, C.J.; Scherer, G.W. Sol-Gel Science: The Physics and Chemistry of Sol-Gel Processing; Academic Press: Boston, MA, USA, 2013. [Google Scholar]
  33. Al-Oweini, R.; El-Rassy, H. Synthesis and Characterization by FTIR Spectroscopy of Silica Aerogels Prepared Using Several Si(OR)4 and R′′Si(OR′)3 Precursors. J. Mol. Struct. 2009, 919, 140–145. [Google Scholar] [CrossRef]
  34. Colthup, N.B.; Daly, L.H.; Wiberley, S.E. Chapter 12—Compounds Containing Boron, Silicon, Phosphorus, Sulfur, or Halogen. In Introduction to Infrared and Raman Spectroscopy, 3rd ed.; Colthup, N.B., Daly, L.H., Wiberley, S.E., Eds.; Academic Press: San Diego, CA, USA, 1990; pp. 355–385. [Google Scholar] [CrossRef]
  35. Colthup, N.B.; Daly, L.H.; Wiberley, S.E. Chapter 13—Major Spectra–Structure Correlations by Spectral Regions. In Introduction to Infrared and Raman Spectroscopy, 3rd ed.; Colthup, N.B., Daly, L.H., Wiberley, S.E., Eds.; Academic Press: San Diego, CA, USA, 1990; pp. 387–481. [Google Scholar] [CrossRef]
  36. Rajendran, S.; Uma, T. Effect of ZrO2 on Conductivity of PVC–LiBF4–DBP Polymer Electrolytes. Mater. Lett. 2000, 44, 208–214. [Google Scholar] [CrossRef]
  37. Rajendran, S.; Uma, T. Conductivity Studies on PVC/PMMA Polymer Blend Electrolyte. Mater. Lett. 2000, 44, 242–247. [Google Scholar] [CrossRef]
  38. Ramesh, S.; Leen, K.H.; Kumutha, K.; Arof, A.K. FTIR Studies of PVC/PMMA Blend Based Polymer Electrolytes. Spectrochim Acta A Mol. Biomo. Spectrosc. 2007, 66, 1237–1242. [Google Scholar] [CrossRef]
  39. Soman, V.V.; Kelkar, D.S. FTIR Studies of Doped PMM—PVC Blend System. Macromol. Symp. 2009, 277, 152–161. [Google Scholar] [CrossRef]
  40. Colthup, N.B.; Daly, L.H.; Wiberley, S.E. Chapter 8—Aromatic and Heteroaromatic Rings. In Introduction to Infrared and Raman Spectroscopy, 3rd ed.; Colthup, N.B., Daly, L.H., Wiberley, S.E., Eds.; Academic Press: San Diego, CA, USA, 1990; pp. 261–288. [Google Scholar] [CrossRef]
  41. Matuana, L.M.; Kamdem, D.P.; Zhang, J. Photoaging and Stabilization of Rigid PVC/Wood-Fiber Composites. J. Appl. Polym. Sci. 2001, 80, 1943–1950. [Google Scholar] [CrossRef]
  42. Gallouze, N.; Belhaneche-Bensemra, N. Influence of Polluted Atmospheres on the Natural Aging of Poly(Vinyl Chloride) Stabilized with Epoxidized Sunflower Oil. J. Appl. Polym. Sci. 2008, 110, 1973–1978. [Google Scholar] [CrossRef]
  43. Janorkar, A.V.; Metters, A.T.; Hirt, D.E. Degradation of Poly(L-Lactide) Films under Ultraviolet-Induced Photografting and Sterilization Conditions. J. Appl. Polym. Sci. 2007, 106, 1042–1047. [Google Scholar] [CrossRef]
  44. Copinet, A.; Bertrand, C.; Govindin, S.; Coma, V.; Couturier, Y. Effects of Ultraviolet Light (315 Nm), Temperature and Relative Humidity on the Degradation of Polylactic Acid Plastic Films. Chemosphere 2004, 55, 763–773. [Google Scholar] [CrossRef] [PubMed]
  45. Kaynak, C.; Kaygusuz, I. Consequences of Accelerated Weathering in Polylactide Nanocomposites Reinforced with Halloysite Nanotubes. J. Compos. Mater. 2016, 50, 365–375. [Google Scholar] [CrossRef]
  46. Yang, X.; Jiang, X.; Hu, J.; Wang, F.; Hu, C. Relationship between Physical and Mechanical Properties of Accelerated Weathering and Outdoor Weathering of PVC-Coated Membrane Material under Tensile Stress. J. Ind. Text. 2017, 47, 197–210. [Google Scholar] [CrossRef]
  47. Pagacz, J.; Chrzanowski, M.; Krucińska, I.; Pielichowski, K. Thermal Aging and Accelerated Weathering of PVC/MMT Nanocomposites: Structural and Morphological Studies. J. Appl. Polym. Sci. 2015, 132, 42090. [Google Scholar] [CrossRef]
  48. Islam, M.S.; Pickering, K.L.; Foreman, N.J. Influence of Accelerated Ageing on the Physico-Mechanical Properties of Alkali-Treated Industrial Hemp Fibre Reinforced Poly(Lactic Acid) (PLA) Composites. Polym. Degrad. Stab. 2010, 95, 59–65. [Google Scholar] [CrossRef] [Green Version]
  49. Torres-Huerta, A.M.; Palma-Ramírez, D.; Domínguez-Crespo, M.A.; Del Angel-López, D.; de la Fuente, D. Comparative Assessment of Miscibility and Degradability on PET/PLA and PET/Chitosan Blends. Eur. Polym. J. 2014, 61, 285–299. [Google Scholar] [CrossRef]
  50. Wongwitdecha, N.; Marsden, C.A. Social Isolation Increases Aggressive Behaviour and Alters the Effects of Diazepam in the Rat Social Interaction Test. Behav. Brain Res. 1996, 75, 27–32. [Google Scholar] [CrossRef]
  51. Hawkins, M.F.; Fuller, R.D.; Baumeister, A.A.; McCallum, M.D. Effects in the Rat of Intranigral Morphine and DAGO on Eating and Gnawing Induced by Stress. Pharmacol. Biochem. Behav. 1994, 49, 737–740. [Google Scholar] [CrossRef]
  52. Curiosity Rats, Curiousv. Available online: http://www.curiousv.com/curiosityrats/files/infopsych.html (accessed on 31 May 2018).
  53. Nevison, C.M.; Hurst, J.L.; Barnard, C.J. Why Do Male ICR(CD-1) Mice Perform Bar-Related (Stereotypic) Behaviour? Behav. Processes 1999, 47, 95–111. [Google Scholar] [CrossRef]
  54. Zeredo, J.L.; Kumei, Y.; Shibazaki, T.; Yoshida, N.; Toda, K. Measuring Biting Behavior Induced by Acute Stress in the Rat. Behav. Res. Methods 2009, 41, 761–764. [Google Scholar] [CrossRef] [PubMed] [Green Version]
  55. Crespo, J.E.; Sánchez, L.; García, D.; López, J. Study of the Mechanical and Morphological Properties of Plasticized PVC Composites Containing Rice Husk Fillers. J. Reinf. Plast. Comp. 2008, 27, 229–243. [Google Scholar] [CrossRef]
  56. Yang, H.-S.; Kim, H.-J.; Park, H.-J.; Lee, B.-J.; Hwang, T.-S. Effect of Compatibilizing Agents on Rice-Husk Flour Reinforced Polypropylene Composites. Compos. Struct. 2007, 77, 45–55. [Google Scholar] [CrossRef]
  57. Zhu, A.; Cai, A.; Zhang, J.; Jia, H.; Wang, J. PMMA-Grafted-Silica/PVC Nanocomposites: Mechanical Performance and Barrier Properties. J. Appl. Polym. Sci. 2008, 108, 2189–2196. [Google Scholar] [CrossRef]
  58. Gil, N.; Saska, M.; Negulescu, I. Evaluation of the Effects of Biobased Plasticizers on the Thermal and Mechanical Properties of Poly(Vinyl Chloride). J. Appl. Polym. Sci. 2006, 102, 1366–1373. [Google Scholar] [CrossRef]
  59. Zurina, M.; Ismail, H.; Bakar, A.A. Partial Replacement of Silica by Rice Husk Powder in Polystyrene–Styrene Butadiene Rubber Blends. J. Reinf. Plast. Comp. 2004, 23, 1397–1408. [Google Scholar] [CrossRef]
  60. Klapiszewski, Ł.; Pawlak, F.; Tomaszewska, J.; Jesionowski, T. Preparation and Characterization of Novel PVC/Silica–Lignin Composites. Polymers 2015, 7, 1767–1788. [Google Scholar] [CrossRef] [Green Version]
  61. Fasihi, M.; Arabzadeh, R.; Moghbeli, M.R. Effect of Silica Particles on Adhesion Strength of Polyvinyl Chloride Coatings on Metal Substrates. Iran J. Chem. Chem. Eng. 2017, 14, 74–82. [Google Scholar]
  62. Jia, P.; Hu, L.; Feng, G.; Bo, C.; Zhou, J.; Zhang, M.; Zhou, Y. Design and Synthesis of a Castor Oil Based Plasticizer Containing THEIC and Diethyl Phosphate Groups for the Preparation of Flame-Retardant PVC Materials. RSC Adv. 2017, 7, 897–903. [Google Scholar] [CrossRef] [Green Version]
  63. Jia, P.; Hu, L.; Zhang, M.; Feng, G.; Zhou, Y. Phosphorus Containing Castor Oil Based Derivatives: Potential Non-Migratory Flame Retardant Plasticizer. Eur. Polym. J. 2017, 87, 209–220. [Google Scholar] [CrossRef]
  64. Bueno-Ferrer, C.; Garrigós, M.C.; Jiménez, A. Characterization and Thermal Stability of Poly(Vinyl Chloride) Plasticized with Epoxidized Soybean Oil for Food Packaging. Polym. Degrad. Stabil. 2010, 95, 2207–2212. [Google Scholar] [CrossRef]
  65. Nihul, P.G.; Mhaske, S.T.; Shertukde, V.V. Epoxidized Rice Bran Oil (ERBO) as a Plasticizer for Poly(Vinyl Chloride) (PVC). Iran Polym. J. 2014, 23, 599–608. [Google Scholar] [CrossRef]
  66. Xie, X.-L.; Liu, Q.-X.; Li, R.K.-Y.; Zhou, X.-P.; Zhang, Q.-X.; Yu, Z.-Z.; Mai, Y.-W. Rheological and Mechanical Properties of PVC/CaCO3 Nanocomposites Prepared by in Situ Polymerization. Polymers 2004, 45, 6665–6673. [Google Scholar] [CrossRef]
  67. Mohagheghian, M.; Sadeghi, M.; Chenar, M.P.; Naghsh, M. Gas Separation Properties of Polyvinylchloride (PVC)-Silica Nanocomposite Membrane. Korean J. Chem. Eng. 2014, 31, 2041–2050. [Google Scholar] [CrossRef]
  68. Lavina, S.; Negro, E.; Pace, G.; Gross, S.; Depaoli, G.; Vidali, M.; Di Noto, V. Dielectric Low-k Composite Films Based on PMMA, PVC and Methylsiloxane-Silica: Synthesis, Characterization and Electrical Properties. J. Non-Cryst Solids. 2007, 353, 2878–2888. [Google Scholar] [CrossRef]
  69. Varma-Nair, M.; Wunderlich, B. Non Isothermal Heat Capacities and Chemical Reactions Using a Modulated DSC. J. Therm. Anal. Calorim. 1996, 46, 879–892. [Google Scholar] [CrossRef]
  70. Ari, G.A.; Aydin, I. A Study on Fusion and Rheological Behaviors of PVC/SiO2 Microcomposites and Nanocomposites: The Effects of SiO2 Particle Size. Polym. Eng. Sci. 2011, 51, 1574–1579. [Google Scholar] [CrossRef]
  71. Levchik, S.V.; Weil, E.D. Overview of the Recent Literature on Flame Retardancy and Smoke Suppression in PVC. Polym. Adv. Technol. 2005, 16, 707–716. [Google Scholar] [CrossRef]
  72. Liang, G.G.; Cook, W.D.; Sautereau, H.J.; Tcharkhtchi, A. Diallyl Orthophthalate as a Reactive Plasticizer for Improving PVC Processibility, Part II: Rheology during Cure. Polymers 2009, 50, 2635–2642. [Google Scholar] [CrossRef]
  73. Sugimoto, M.; Hida, H.; Taniguchi, T.; Koyama, K.; Aoki, Y. Rheological Properties of Poly(Vinyl Chloride)/Plasticizer Systems—Relation between Sol–Gel Transition and Elongational Viscosity. Rheol. Actaa 2007, 46, 957–964. [Google Scholar] [CrossRef]
  74. Kamibayashi, M.; Ogura, H.; Otsubo, Y. Rheological Behavior of Suspensions of Silica Nanoparticles in Associating Polymer Solutions. Ind. Eng. Chem. Res. 2006, 45, 6899–6905. [Google Scholar] [CrossRef]
  75. Otsubo, Y. Effect of Polymer Adsorption on the Rheological Behavior of Silica Suspensions. J. Colloid Interface Sci. 1986, 112, 380–386. [Google Scholar] [CrossRef]
Jcs 06 00008 g001 550
Figure 1. Pictures of; (a) CO; (b) SiCO; (c) DB/ZnSt.
Figure 1. Pictures of; (a) CO; (b) SiCO; (c) DB/ZnSt.
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Figure 2. Experiment; (a) 2 rats for cage 1 and cage 2; (b) a rat in cage 3.
Figure 2. Experiment; (a) 2 rats for cage 1 and cage 2; (b) a rat in cage 3.
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Figure 3. Pictures of; (a) specimens for anti-rodent testing; (b) testing environment.
Figure 3. Pictures of; (a) specimens for anti-rodent testing; (b) testing environment.
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Figure 4. (a) Scanned region in the SEM micrographs of DB/ZnSt particles; (b) elemental mapping of the scanned area; (c) EDAX spectra of DB/ZnSt particles.4c.
Figure 4. (a) Scanned region in the SEM micrographs of DB/ZnSt particles; (b) elemental mapping of the scanned area; (c) EDAX spectra of DB/ZnSt particles.4c.
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Figure 5. SEM micrographs of (a) PVC; (b) I.1; (c) I.2; (d) I.3; (e) I.4; (f) II.1; (g) II.2; (h) II.3; (i) II.4.
Figure 5. SEM micrographs of (a) PVC; (b) I.1; (c) I.2; (d) I.3; (e) I.4; (f) II.1; (g) II.2; (h) II.3; (i) II.4.
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Figure 6. SEM micrographs with magnification 1000× of (a) PVC; (b) I.1; (c) II.4.
Figure 6. SEM micrographs with magnification 1000× of (a) PVC; (b) I.1; (c) II.4.
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Figure 7. ATR-FTIR spectrums of PVC, I.4, and II.4 before and after aging in weathering.
Figure 7. ATR-FTIR spectrums of PVC, I.4, and II.4 before and after aging in weathering.
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Figure 8. Effect of substances concentration, number of rats and time on percentage of weight loss.
Figure 8. Effect of substances concentration, number of rats and time on percentage of weight loss.
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Figure 9. Stress-strain curves of PVC compound and PVC composites.
Figure 9. Stress-strain curves of PVC compound and PVC composites.
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Figure 10. DSC 2nd heating curve of PVC compound and PVC composites.
Figure 10. DSC 2nd heating curve of PVC compound and PVC composites.
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Figure 11. TGA of PVC and PVC composites.
Figure 11. TGA of PVC and PVC composites.
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Figure 12. DTG of PVC and PVC composites.
Figure 12. DTG of PVC and PVC composites.
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Figure 13. (a) G′; (b) G″ of PVC and the PVC composites.
Figure 13. (a) G′; (b) G″ of PVC and the PVC composites.
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Figure 14. Shear viscosity of PVC and the PVC composites.
Figure 14. Shear viscosity of PVC and the PVC composites.
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Table
Table 1. Content of anti-rodent samples.
Table 1. Content of anti-rodent samples.
SamplesB/ZnSt (wt%)SiCO (wt%)
Set II.11.9612.16
I.21.9614.47
I.31.9618.75
I.41.9623.53
Set IIII.1-12.16
II.2-14.47
II.3-18.75
II.4-23.53
Table
Table 2. Experimental design of gnawing test.
Table 2. Experimental design of gnawing test.
Testing Period
Animal Cage		1st Month2nd Month3rd Month
Cage 1BlankSet ISet II
Cage 2Set ISet IIBlank
Cage 3Set IIBlankSet I
Table
Table 3. Vibrational modes and wavenumbers observed in PVC compound [36,37,38,39,40].
Table 3. Vibrational modes and wavenumbers observed in PVC compound [36,37,38,39,40].
Description of VibrationsWavenumbers (cm−1)
C-H stretching2850–2958
C=O stretching vibration1722–1725
C-H bending1421–1424
C-H rocking1257–1260
trans C-H wagging961
–C–C– stretch870–873
C-Cl stretching750–850
cis C-H wagging615
Table
Table 4. Analysis of variance for the percentage of weight loss.
Table 4. Analysis of variance for the percentage of weight loss.
SourceDFAdj SSAdj MSF-Valuep-Value
Sample837,7154714.323.580.000
Cage294264713.223.570.000
Month21639819.34.100.022
Error5911,796199.9
Lack-of-Fit147072505.2
Pure Error454723105.04.810.000
Total7160,575
Table
Table 5. Grouping information of samples using the Tukey method and 95% confidence.
Table 5. Grouping information of samples using the Tukey method and 95% confidence.
SettingNMean of Weight Loss (%)Grouping
Blank2459.74A
II.1632.48B
II.2626.52B, C
I.1613.09B, C
II.3612.65B, C
I.2610.92B, C
I.368.70B, C
I.467.01B, C
II.461.68C
Table
Table 6. Grouping information of cage using the Tukey method and 95% confidence.
Table 6. Grouping information of cage using the Tukey method and 95% confidence.
CageNMean of Weight Loss (%)Grouping
C32435.28A
C22412.73B
C1249.59B
Table
Table 7. Grouping information of period of time using the Tukey method and 95% confidence.
Table 7. Grouping information of period of time using the Tukey method and 95% confidence.
MonthNMean of Weight Loss (%)Grouping
12425.9047A
22416.4909A, B
32415.2018B
Table
Table 8. Tensile strength, tensile modulus and elongation at break of PVC and all PVC composites.
Table 8. Tensile strength, tensile modulus and elongation at break of PVC and all PVC composites.
CodeTensile Strength
(MPa)		Elongation at Break
(%)		Tensile Modulus
(MPa)
PVC16.42 ± 1.1522.15 ± 74.110.76 ± 0.5
I.112.23 ± 1.0531.21 ± 82.99.61 ± 0.3
I.212.03 ± 0.5514.56 ± 42.19.66 ± 0.9
I.310.65 ± 0.4459.46 ± 47.09.72 ± 0.6
I.48.09 ± 0.8321.49 ± 62.59.38 ± 0.5
II.113.13 ± 0.8508.79 ± 64.48.95 ± 0.5
II.212.51 ± 0.5489.58 ± 34.09.25 ± 0.3
II.311.03 ± 0.5441.64 ± 43.59.58 ± 0.5
II.48.41 ± 0.6318.60 ± 51.89.61 ± 0.4
Table
Table 9. Thermal characteristics of PVC and PVC composites.
Table 9. Thermal characteristics of PVC and PVC composites.
SampleTonset1
(°C)		Tonset2
(°C)		T1%
(°C)		T5%
(°C)		T50%
(°C)		Tmax1
(°C)		Tmax2
(°C)		Ash Content
(%wt)
PVC293.59432.53257.87283.57326.55313.66443.3428.66
I.1272.11433.69239.77267.40324.59294.80455.2829.34
I.2273.70430.22243.04268.46328.22297.45457.1629.43
I.3275.25440.48240.91268.85331.45298.30458.7230.50
I.4277.18449.96234.40271.01339.35299.96457.1731.22
II.1291.49454.29260.14284.82337.02315.70457.0925.56
II.2290.81446.31256.56285.67340.25315.37459.6626.67
II.3290.09442.24252.82286.00340.78314.22454.6827.42
II.4288.93430.87242.22283.07348.68314.02453.1427.85
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Techawinyutham, L.; Prasarnsri, A.; Siengchin, S.; Dangtungee, R.; Rangappa, S.M. Anti-Gnawing, Thermo-Mechanical and Rheological Properties of Polyvinyl Chloride: Effect of Capsicum Oleoresin and Denatonium Benzoate. J. Compos. Sci. 2022, 6, 8. https://doi.org/10.3390/jcs6010008

AMA Style

Techawinyutham L, Prasarnsri A, Siengchin S, Dangtungee R, Rangappa SM. Anti-Gnawing, Thermo-Mechanical and Rheological Properties of Polyvinyl Chloride: Effect of Capsicum Oleoresin and Denatonium Benzoate. Journal of Composites Science. 2022; 6(1):8. https://doi.org/10.3390/jcs6010008

Chicago/Turabian Style

Techawinyutham, Laongdaw, Arnuparb Prasarnsri, Suchart Siengchin, Rapeephun Dangtungee, and Sanjay Mavinkere Rangappa. 2022. "Anti-Gnawing, Thermo-Mechanical and Rheological Properties of Polyvinyl Chloride: Effect of Capsicum Oleoresin and Denatonium Benzoate" Journal of Composites Science 6, no. 1: 8. https://doi.org/10.3390/jcs6010008

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