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19 pages, 4089 KB

Open AccessArticle

Improving the Strength of Eucalyptus Wood Joints Through Optimized Rotary Welding Conditions

by Jiankun Liang, Xiao Zhong, Yuqi Yang, Guifen Yang, Shuang Yin, Feiyan Gong, Chuchu Chen, Huali Li, Tong Meng, Yulan Jian, De Li, Caihong Long, Zhixian Song and Zhigang Wu

Materials 2025, 18(24), 5596; https://doi.org/10.3390/ma18245596 - 12 Dec 2025

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Abstract

Conventional wood connections rely on adhesives and metal fasteners, causing environmental concerns. Wood rotary welding offers an adhesive-free alternative. This study systematically investigated rotary welding of eucalyptus wood, evaluating process parameters’ effects on joint performance. Chemical and microstructural transformations at the welding interface [...] Read more.

Conventional wood connections rely on adhesives and metal fasteners, causing environmental concerns. Wood rotary welding offers an adhesive-free alternative. This study systematically investigated rotary welding of eucalyptus wood, evaluating process parameters’ effects on joint performance. Chemical and microstructural transformations at the welding interface were characterized using FT-IR, XPS, XRD, SEM, and TGA. Optimal parameters significantly enhanced connection strength compared to unwelded specimens. The welding process induced partial degradation of hemicellulose and cellulose, forming new chemical bonds and increasing carbonyl compounds. XRD revealed increased wood crystallinity, while SEM showed tighter interfaces with enhanced mechanical interlocking. TGA confirmed improved thermal stability at the welded interface. The findings demonstrate that rotary welding improves eucalyptus wood joint strength through combined chemical, thermal, and structural modifications, providing guidance for optimizing welding protocols in sustainable wood manufacturing. Full article

(This article belongs to the Special Issue Synthesis–Processing–Structure–Property Interrelationship of Multifunctional Polymeric Materials and Natural Polymers)

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16 pages, 4276 KB

Open AccessArticle

One-Step Synthesis and Performance Evaluation of a Sucrose–Glyoxylic Acid Wood Adhesive

by Jiankun Liang, Yuqi Yang, Longxu Wu, Ningyuan Zuo, Qiuli Li, Tong Meng, Chuchu Chen, Huali Li, Caihong Long, Zhixian Song, Yulan Jian, De Li and Zhigang Wu

Materials 2025, 18(23), 5386; https://doi.org/10.3390/ma18235386 - 28 Nov 2025

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Abstract

Environmental and health concerns drive research into sustainable bio-based wood adhesives. This study utilized widely available and economical sucrose and glyoxylic acid as raw materials to prepare a wood adhesive via a one-step method. The effects of glyoxylic acid content on the adhesive [...] Read more.

Environmental and health concerns drive research into sustainable bio-based wood adhesives. This study utilized widely available and economical sucrose and glyoxylic acid as raw materials to prepare a wood adhesive via a one-step method. The effects of glyoxylic acid content on the adhesive structure, properties, and plywood application performance were statistically investigated. The results demonstrated successful esterification and acetalizations between glyoxylic acid and sucrose, forming a dense three-dimensional cross-linked network that enhanced bonding performance, water resistance, and thermal stability. At 40% glyoxylic acid content, the adhesive exhibited optimal comprehensive properties: the wet shear strengths of 1.39 MPa (63 °C) and 1.17 MPa (93 °C) that substantially exceeded GB/T 17657-2022 requirements. This study provides novel insights and a practical foundation for high-value sucrose utilization and green wood adhesive development. Full article

(This article belongs to the Special Issue Synthesis–Processing–Structure–Property Interrelationship of Multifunctional Polymeric Materials and Natural Polymers)

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13 pages, 1286 KB

Open AccessArticle

Effect of Poly (Vinyl Alcohol) on the Properties of Cold-Setting Melamine–Urea–Formaldehyde Resin Adhesive

by Jiankun Liang, Bengang Zhang, Longxu Wu, Yuqi Yang, Caihong Long, Zhixian Song, Hui Yang and Zhigang Wu

Materials 2025, 18(22), 5125; https://doi.org/10.3390/ma18225125 - 11 Nov 2025

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Abstract

This study investigates how poly (vinyl alcohol) (PVA) influences melamine–urea–formaldehyde (MUF) resin, particularly regarding tensile properties, bonding strength, water resistance, curing temperature, chemical structure, and microscopic morphology. By altering the PVA content, we observed changes in the tensile strength and elongation of MUF [...] Read more.

This study investigates how poly (vinyl alcohol) (PVA) influences melamine–urea–formaldehyde (MUF) resin, particularly regarding tensile properties, bonding strength, water resistance, curing temperature, chemical structure, and microscopic morphology. By altering the PVA content, we observed changes in the tensile strength and elongation of MUF resin. The tensile strength peaked at a 2% PVA addition. PVA significantly enhanced the dry, cold water, and boiling water bonding strengths of MUF resin, with the most notable effect at a 10% addition. A low PVA addition (2%) notably improved the water resistance of glued wood. Differential scanning calorimetry revealed that PVA increased the curing temperature of MUF resin, though excessive PVA led to a decrease. Nuclear magnetic resonance analysis showed changes in chemical bonds after PVA modification, indicating increased polymerization. X-ray diffraction and scanning electron microscopy analyses further confirmed the effects of PVA on the crystal structure and microscopic morphology of MUF resin, with modified resins exhibiting higher toughness fracture characteristics. These findings suggest that PVA can effectively enhance the overall performance of MUF resin, making it more suitable for applications of glued wood. Full article

(This article belongs to the Special Issue Synthesis–Processing–Structure–Property Interrelationship of Multifunctional Polymeric Materials and Natural Polymers)

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19 pages, 5641 KB

Open AccessArticle

One-Pot Preparation of Easily Dispersible Hexagonal Mg(OH)₂ Modified with THPS and Its Flame-Retardant EVA Copolymer

by Xia Liu, Haihui Xu and Jinyang Chen

Materials 2025, 18(21), 4847; https://doi.org/10.3390/ma18214847 - 23 Oct 2025

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Abstract

As an eco-friendly flame-retardant additive, magnesium hydroxide (MH) is widely employed in low-smoking, halogen-free polymer materials due to its environmentally benign nature. In order to enhance flame retardancy performance, the modified MH was modified with tetrakis(hydroxymethyl)phosphonium sulfate (THPS) by a one-pot hydrothermal method. [...] Read more.

As an eco-friendly flame-retardant additive, magnesium hydroxide (MH) is widely employed in low-smoking, halogen-free polymer materials due to its environmentally benign nature. In order to enhance flame retardancy performance, the modified MH was modified with tetrakis(hydroxymethyl)phosphonium sulfate (THPS) by a one-pot hydrothermal method. The resulting morphology was characterized using scanning electron microscopy (SEM), and it shows the dispersion of nanometer particles and almost no aggregation. The X-ray photoelectron spectroscopy (XPS) along with Raman spectroscopy show that the THPS is connected with the Mg(OH)₂ by chemical bond. The sample was incorporated into ethylene–vinyl acetate (EVA) to evaluate the flame retardancy was assessed via limiting oxygen index (LOI) and vertical burning tests (UL-94). The results show that THPS modified MH effectively enhanced the flame retardancy, achieving a V-0 rating and an LOI value of 31.3%. In addition, the composites retain good mechanical integrity. The thermal analysis with TGA and DTG shows the formation of the MgO decomposition product, along with water vapor and phosphorus-containing radicals released by modified MH in the combustion process, forming a strong flame-retardant protective layer. In addition, the maximum smoke density of EVA/MHP-3 composite was 155.4, lower than 411.3 for EVA/MH, with a 62.2% reduction in total smoke production. The result shows that THPS is effective for improving the flame-retardant efficiency of inorganic metal hydroxide in polymer composites. Full article

(This article belongs to the Special Issue Synthesis–Processing–Structure–Property Interrelationship of Multifunctional Polymeric Materials and Natural Polymers)

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15 pages, 2375 KB

Open AccessArticle

The Effect of Various Types of Polymeric Packaging Materials on the Quality of Copioba Cassava Flour

by Andrea Limoeiro Carvalho, Fabiane Cerqueira de Almeida, Lucas Guimarães Cardoso, Ederlan de Souza Ferreira, Geany Peruch Camilloto and Carolina Oliveira de Souza

Materials 2025, 18(20), 4768; https://doi.org/10.3390/ma18204768 - 17 Oct 2025

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Abstract

This study assessed the impact of commercial packaging on the stability and identity of Copioba cassava flour. Flour was packaged in low-density polyethylene (LDPE), polypropylene (PP), and metallized biaxially oriented polypropylene (BOPP) films. Quality changes over time were evaluated via moisture content, water [...] Read more.

This study assessed the impact of commercial packaging on the stability and identity of Copioba cassava flour. Flour was packaged in low-density polyethylene (LDPE), polypropylene (PP), and metallized biaxially oriented polypropylene (BOPP) films. Quality changes over time were evaluated via moisture content, water activity (a_w), pH, titratable acidity, texture/hardness, color, fatty acid composition, and specific microorganisms. Moisture content and a_w increased in the LDPE-packaged flour and the control group. At the end of the storage period, levels of fatty acids had decreased by 55.81–68.28%, with only minor changes in a_w. There was a rise in yeast and mold levels up to 4 log CFU/g in flour packaged in LDPE films. In contrast, the levels of Bacillus cereus in flour packaged in PP and BOPP ranged from <1 to 2.30 log CFU/g. PP and BOPP films exhibited the most effective performance among the packaging materials evaluated. The results obtained in this study will contribute to the pursuit of a Geographical Indication GI certification by providing information about the best packaging type for preserving the unique characteristics of Copioba cassava flour, as no study has previously reported on the best type of packaging material for Copioba flour. Full article

(This article belongs to the Special Issue Synthesis–Processing–Structure–Property Interrelationship of Multifunctional Polymeric Materials and Natural Polymers)

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21 pages, 3721 KB

Open AccessArticle

Analysis of the Mechanical Properties of Polymer Composites Reinforced with Charcoal Particulate

by Josinaldo O. Dias, Rayara Davel Siqueira, Bruno Fonseca Coelho and Amanda O. Conceição

Materials 2025, 18(12), 2746; https://doi.org/10.3390/ma18122746 - 11 Jun 2025

Cited by 1 | Viewed by 1083

Abstract

Naturally reinforced polymer composites have emerged as a promising sustainable alternative to conventional polymers due to their biodegradability. This study aimed to develop a composite by incorporating charcoal particulate into a recycled high-density polyethylene (HDPE) matrix and evaluating its mechanical properties. Two manufacturing [...] Read more.

Naturally reinforced polymer composites have emerged as a promising sustainable alternative to conventional polymers due to their biodegradability. This study aimed to develop a composite by incorporating charcoal particulate into a recycled high-density polyethylene (HDPE) matrix and evaluating its mechanical properties. Two manufacturing methods (compression molding and extrusion) and four charcoal concentrations (0, 5, 10, and 15%) were investigated. Characterization involved tensile tests and non-destructive evaluation using wave propagation and ultrasound techniques. The experiment followed a completely randomized design with a 4 × 2 factorial arrangement, comprising eight treatments. Statistical analysis was conducted using Tukey’s test for multiple comparisons. The tensile test results indicated that the manufacturing methods of compression molding and extrusion led to significant differences in the elastic modulus (MOE) variable, in contrast to the results observed for the maximum stress variable. However, the addition of charcoal particulate caused a notable reduction in maximum tensile strength (approximately 50%), from 20.17 to 11.19 MPa, and a 22% decrease in the MOE, from 310.93 to 242.88 MPa, compared to unreinforced HDPE. Non-destructive testing confirmed the tensile test findings, also indicating a reduction in MOE. Despite the decline in mechanical properties, these composites remain viable for applications prioritizing lightweight structures, thermal insulation, or chemical resistance. Furthermore, their use enhances the valorization of waste and increases sustainability by reducing environmental impact. Full article

(This article belongs to the Special Issue Synthesis–Processing–Structure–Property Interrelationship of Multifunctional Polymeric Materials and Natural Polymers)

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16 pages, 2619 KB

Open AccessArticle

New (Co)poly(hydroxyimide)s Based on 4,4′-Oxydiphthalic Anhydride—Effect of Composition on Properties, Including Gas Transport Ability

by Agnieszka Katarzyna Pająk, Andrzej Jankowski and Ewa Schab-Balcerzak

Materials 2025, 18(10), 2193; https://doi.org/10.3390/ma18102193 - 9 May 2025

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Abstract

This paper presents novel soluble (co)poly(hydroxyimide)s ((co)PIOH) based on 4,4′-oxydiphthalic anhydride (ODPA), 3,3′-dihydroxybenzidine (HAB), and 3,6-diaminodurene (D) with the 3/1, 1/1, and 1/3 HAB/D ratios. This chemical structure of the compounds provides the possibility of their future modification through the thermal rearrangement (polybenzoxazoles) [...] Read more.

This paper presents novel soluble (co)poly(hydroxyimide)s ((co)PIOH) based on 4,4′-oxydiphthalic anhydride (ODPA), 3,3′-dihydroxybenzidine (HAB), and 3,6-diaminodurene (D) with the 3/1, 1/1, and 1/3 HAB/D ratios. This chemical structure of the compounds provides the possibility of their future modification through the thermal rearrangement (polybenzoxazoles) or functionalization via Mitsunobu reaction (azo side-chain polyimides), i.e., obtaining new materials with interesting properties and therefore with expanded applications. Copolymers were characterized via FTIR, NMR, XRD, and GPC methods to confirm their structure, composition, and molar masses. The effect of copolymer composition on the thermal, mechanical, optical, and permeation properties studied for He, O₂, N₂, and CO₂, as well as hydrophobicity, was investigated. They exhibited a large interval between the glass transition temperature and the decomposition temperature, making them promising for the thermoforming technique. Transmittance above 90% was noted in the visible range for all (co)PIOH films deposited on a glass substrate. Young’s modulus of fabricated membranes was in the range of 2.37 to 3.38 GPa. The highest permeability coefficients were recorded for (co)PIOH with a 1:3 HAB-to D-ratio. Full article

(This article belongs to the Special Issue Synthesis–Processing–Structure–Property Interrelationship of Multifunctional Polymeric Materials and Natural Polymers)

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24 pages, 4182 KB

Open AccessArticle

New Biobased Plasticizers for PVC Derived from Saturated Dimerized Fatty Acids

by Patryk Dziendzioł, Sylwia Waśkiewicz and Katarzyna Jaszcz

Materials 2025, 18(9), 2155; https://doi.org/10.3390/ma18092155 - 7 May 2025

Viewed by 991

Abstract

Phthalates are compounds widely used as very effective plasticizers of PVC. Unfortunately, they are also widely known to be endocrine disruptors and are detrimental to human health and the environment. For this reason, environmentally friendly plasticizers are being intensively sought after in response [...] Read more.

Phthalates are compounds widely used as very effective plasticizers of PVC. Unfortunately, they are also widely known to be endocrine disruptors and are detrimental to human health and the environment. For this reason, environmentally friendly plasticizers are being intensively sought after in response to the market needs in the context of sustainable development and legislative changes regarding the use of phthalates. Our research presents an innovative approach to addressing this problem. In this paper, we propose new biobased oligoesters as non-toxic and harmless plasticizers of poly(vinyl chloride). New plasticizers were obtained by polyesterification of saturated dimerized fatty acid (DFA), adipic acid (ADA), triethylene glycol (TEG), and 2-ethylhexanol (2-EH), and were characterized by nuclear magnetic resonance, size exclusion chromatography, and viscosity analyses. The compatibility of the obtained oligoesters with PVC was determined using the method for obtaining PVC films by casting from a THF solution. Selected plasticizers were used to obtain PVC blends at 50 phr. They were then tested for plasticizer migration, hardness, thermogravimetric analysis, differential scanning calorimetry, and mechanical strength. Their properties were compared with the commercially available monomeric plasticizers di(2-ethylhexyl) terephthalate and di(2-ethylhexyl) adipate. The conducted study shows that the oligoesters obtained at a molar ratio of ADA to DFA of 9:1 and using an excess of 2-EH exhibit very good compatibility and plasticizing ability. The use of higher amounts of DFA worsens the compatibility of the oligoesters with PVC. However, a 4:1 ADA-to-DFA molar ratio produced results that still allow for the use of these compounds as plasticizers at lower concentrations or in combination with other plasticizers. Full article

(This article belongs to the Special Issue Synthesis–Processing–Structure–Property Interrelationship of Multifunctional Polymeric Materials and Natural Polymers)

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25 pages, 107543 KB

Open AccessArticle

Development of a Color-Changing Face Mask for Fever Detection Applications

by Nareerut Jariyapunya, Sunee Hathaiwaseewong, Nanjaporn Roungpaisan and Mohanapriya Venkataraman

Materials 2025, 18(9), 2042; https://doi.org/10.3390/ma18092042 - 29 Apr 2025

Viewed by 1247

Abstract

This study focused on developing a color-changing fabric face mask for fever detection. Reversible Thermochromic Leuco dye (RTL) was applied as an indicator to alert wearers of elevated body temperatures, with the color change occurring at 37.5 °C. Five fabric types Polyethylene (PE), [...] Read more.

This study focused on developing a color-changing fabric face mask for fever detection. Reversible Thermochromic Leuco dye (RTL) was applied as an indicator to alert wearers of elevated body temperatures, with the color change occurring at 37.5 °C. Five fabric types Polyethylene (PE), cotton (CO), a cotton–polyester blend (TC), polyester (PL), and Polyamide (PA) were coated with blue RTL to evaluate their color change responsiveness. The results showed that fabrics with higher thermal conductivity (λ), thermal absorptivity (b), and heat flow (q) exhibited faster color transitions. RTL-coated PE fabric demonstrated the best performance, with a thermal absorptivity of 312.8 Ws^0.5m⁻²K⁻¹ and a heat flow of 2.11 Wm⁻², leading to a rapid color-change time of approximately 4.20 s. Although PE fabric had a lower thermal conductivity (57.6 × 10⁻³ Wm⁻¹K⁻¹) compared to PA fabric 84.56 (10⁻³ Wm⁻¹K⁻¹), the highest thickness 0.65 mm of PA fabric slowed its color-change reaction to 11.8 s. When selecting fabrics for optimal heat transfer, relying solely on fiber type or thermal conductivity (λ) is insufficient. The fabric’s structural properties, particularly thickness, significantly impact thermal resistance (γ). Experimental results suggest that thermal absorptivity and heat flow are more effective criteria for fabric selection, as they directly correlate with color-change performance. Full article

(This article belongs to the Special Issue Synthesis–Processing–Structure–Property Interrelationship of Multifunctional Polymeric Materials and Natural Polymers)

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15 pages, 11371 KB

Open AccessArticle

Thermal and Optical Characterization of Polycarbonate Reflectors Doped with Titanium Dioxide Using Thermography

by Isabella Luísa Vieira Aquino Cassimiro, Juan Ignacio Tomsich, Matheus Pereira Porto, Rosemary do Bom Conselho Sales, Izabella Helena Werneck Soares Rezende, Nathan Funchal de Rezende and Maria Teresa Paulino Aguilar

Materials 2025, 18(7), 1628; https://doi.org/10.3390/ma18071628 - 2 Apr 2025

Cited by 1 | Viewed by 1216

Abstract

Automotive reflectors used in headlamps and rear lamps are typically made of polycarbonate. However, this polymer has low light reflectivity. To enhance its reflective properties, it undergoes a metallization process, which significantly increases production costs. Therefore, it is of interest to develop polymers [...] Read more.

Automotive reflectors used in headlamps and rear lamps are typically made of polycarbonate. However, this polymer has low light reflectivity. To enhance its reflective properties, it undergoes a metallization process, which significantly increases production costs. Therefore, it is of interest to develop polymers that do not require metallization for the manufacturing of automotive reflectors. In this regard, the use of polycarbonate reinforced with titanium dioxide nanoparticles may be an alternative. Studies indicate that incorporating these nanoparticles can improve the degradation temperature and mechanical properties of the composites. In the case of automotive reflectors, in addition to degradation due to temperature, it is crucial to assess the thermal diffusivity and reflectivity of these composites, thus ensuring the lighting performance of the component. Studies on such characteristics in polycarbonates with titanium dioxide nanoparticles are mostly limited to investigations of hardness and optical properties using Raman and UV–Vis spectroscopy tests. This article investigates the thermal and lighting performance of polycarbonate (PC) samples with 10 wt% titanium dioxide (TiO₂) nanoparticles and automotive reflectors with the same chemical composition. The thermal stability of PC and PC-10%TiO₂ was analyzed by thermogravimetry (TGA), whereas the reflectors were evaluated using active infrared thermography. Spectral thermographic analysis in the mid- and long-wave infrared range provided thermal diffusivity data for the polycarbonates and offered important insights into their optical behavior under operational conditions (up to 70 °C). Furthermore, illumination tests were conducted on PC-10%TiO₂, using metalized polymeric reflectors commonly employed in the automotive industry as a reference. The TGA results showed that incorporating 10 wt% TiO₂ into PC increased the degradation temperature from 167 °C to 495 °C. The long-wave infrared emissivity of PC-10%TiO₂ (averaging 0.96) was 3% lower than that of polycarbonate. PC-10%TiO₂ exhibited a thermal diffusivity of 0.20 mm²/s, which was 28.6% lower than that of PC, indicating greater thermal inertia due to the presence of nanoparticles. The lighting performance of the PC-10%TiO₂ reflector was on average 4% lower than that of a commercially available metallized polycarbonate reflector. However, for automotive reflectors, this value meets the sector’s regulatory criteria. These findings suggest that PC-10%TiO₂ has potential for use in the production of internal vehicle lighting reflectors, without significantly compromising light reflectivity, while offering the advantages of thermal stability and reduced heating around the reflector. Full article

(This article belongs to the Special Issue Synthesis–Processing–Structure–Property Interrelationship of Multifunctional Polymeric Materials and Natural Polymers)

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26 pages, 7857 KB

Open AccessArticle

Evaluation of High-Temperature Sterilization Processes: Their Influence on the Mechanical Integrity of Additively Manufactured Polymeric Biomaterials

by Barbara Zbyrad, Małgorzata Zaborniak, Łukasz Kochmański, Katarzyna Jasik, Janusz Kluczyński, Grzegorz Budzik and Paweł Turek

Materials 2025, 18(6), 1356; https://doi.org/10.3390/ma18061356 - 19 Mar 2025

Cited by 2 | Viewed by 1510

Abstract

The continuous advancement of medical technologies and the increasing demand for high-performance medical devices have driven the search for innovative solutions in biomaterials engineering. However, ensuring the sterility of polymeric biomaterials while maintaining their mechanical integrity remains a significant challenge. This research examines [...] Read more.

The continuous advancement of medical technologies and the increasing demand for high-performance medical devices have driven the search for innovative solutions in biomaterials engineering. However, ensuring the sterility of polymeric biomaterials while maintaining their mechanical integrity remains a significant challenge. This research examines how steam sterilization impacts the mechanical properties of four polymeric biomaterials frequently utilized in medical applications: MED610, PEEK, PET-G HT100, and RGD720. Samples were produced using additive manufacturing (AM), specifically Material Jetting (MJT) and Material Extrusion (MEX) processes, and exposed to steam sterilization at 121 °C and 134 °C. A comprehensive verification process was conducted to ensure the effectiveness of sterilization, including pre-sterilization cleaning, disinfection procedures, and the use of process indicators such as the Bowie–Dick test. Mechanical evaluation included bending tests and Rockwell hardness measurements to assess changes in structural integrity and mechanical strength after sterilization. The results revealed that, while some materials exhibited significant alterations in mechanical properties, others demonstrated high resistance to thermal and humidity exposure during sterilization. These findings provide critical insights into the selection and optimization of polymeric biomaterials for sterilizable medical applications, ensuring their durability and safety in clinical use. Full article

(This article belongs to the Special Issue Synthesis–Processing–Structure–Property Interrelationship of Multifunctional Polymeric Materials and Natural Polymers)

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20 pages, 8649 KB

Open AccessArticle

Modeling Key Characteristics of Rigid Polyisocyanurate Foams to Improve Sandwich Panel Production Process

by Mikelis Kirpluks, Beatrise Sture-Skela, Uldis Bariss, Iveta Audzevica, Uldis Pasters, Nikolajs Kurma and Laima Vēvere

Materials 2025, 18(4), 881; https://doi.org/10.3390/ma18040881 - 17 Feb 2025

Viewed by 1958

Abstract

This study explores the optimization of rigid polyisocyanurate (PIR) foam formulations, focusing on foaming kinetics that significantly influence the foam’s microstructure and thermal insulation properties. By systematically altering components such as isocyanate, polyols, catalysts, blowing agents, and additives, this research investigates their effects [...] Read more.

This study explores the optimization of rigid polyisocyanurate (PIR) foam formulations, focusing on foaming kinetics that significantly influence the foam’s microstructure and thermal insulation properties. By systematically altering components such as isocyanate, polyols, catalysts, blowing agents, and additives, this research investigates their effects on key characteristics including cell density, mechanical strength, and thermal conductivity. A statistical approach known as response surface modeling (RSM) was employed to identify relationships between formulation variables and performance metrics. The optimization aimed to enhance thermal insulation while ensuring feasibility for industrial-scale production, particularly for sandwich-type PIR panels. Two distinct formulations, with isocyanate indices of 335 and 400, were developed to assess the impact of various parameters on properties like foaming start time, gel time, and density. The results indicated that the choice of blowing agents and catalysts played a pivotal role in controlling foaming kinetics and final mechanical properties. The optimized formulations exhibited competitive thermal conductivity values (around 23.7 mW/(m·K)) and adequate compression strength (0.32 MPa), aligning closely with commercially available materials. These findings affirm the potential for enhancing production efficiency and performance consistency in the manufacturing of rigid PIR foams for insulation applications. Full article

(This article belongs to the Special Issue Synthesis–Processing–Structure–Property Interrelationship of Multifunctional Polymeric Materials and Natural Polymers)

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Review

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47 pages, 12688 KB

Open AccessReview

Poly(lactide)-Based Materials Modified with Biomolecules: A Review

by Małgorzata Świerczyńska, Marcin H. Kudzin and Jerzy J. Chruściel

Materials 2024, 17(21), 5184; https://doi.org/10.3390/ma17215184 - 24 Oct 2024

Cited by 5 | Viewed by 19941

Abstract

Poly(lactic acid) (PLA) is characterized by unique features, e.g., it is environmentally friendly, biocompatible, has good thermomechanical properties, and is readily available and biodegradable. Due to the increasing pollution of the environment, PLA is a promising alternative that can potentially replace petroleum-derived polymers. [...] Read more.

Poly(lactic acid) (PLA) is characterized by unique features, e.g., it is environmentally friendly, biocompatible, has good thermomechanical properties, and is readily available and biodegradable. Due to the increasing pollution of the environment, PLA is a promising alternative that can potentially replace petroleum-derived polymers. Different biodegradable polymers have numerous biomedical applications and are used as packaging materials. Because the pure form of PLA is delicate, brittle, and is characterized by a slow degradation rate and a low thermal resistance and crystallization rate, these disadvantages limit the range of applications of this polymer. However, the properties of PLA can be improved by chemical or physical modification, e.g., with biomolecules. The subject of this review is the modification of PLA properties with three classes of biomolecules: polysaccharides, proteins, and nucleic acids. A quite extensive description of the most promising strategies leading to improvement of the bioactivity of PLA, through modification with these biomolecules, is presented in this review. Thus, this article deals mainly with a presentation of the major developments and research results concerning PLA-based materials modified with different biomolecules (described in the world literature during the last decades), with a focus on such methods as blending, copolymerization, or composites fabrication. The biomedical and unique biological applications of PLA-based materials, especially modified with polysaccharides and proteins, are reviewed, taking into account the growing interest and great practical potential of these new biodegradable biomaterials. Full article

(This article belongs to the Special Issue Synthesis–Processing–Structure–Property Interrelationship of Multifunctional Polymeric Materials and Natural Polymers)

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