Search Results (212)

A novel biodegradable food packaging material based on cassava thermoplastic starch (TPS) and polybutylene adipate terephthalate (PBAT) blends containing food preservatives was successfully developed using blown-film extrusion. This active packaging is designed to enhance the appearance, taste, and color of food products, while delaying quality deterioration. However, the incorporation of food preservatives directly influences consumer perception, as well as health and safety concerns. Therefore, this research aims to assess the risks associated with both intentionally added substances (IAS) and non-intentionally added substances (NIAS) present in the developed active packaging. The migration of both intentionally and non-intentionally added substances (IAS and NIAS) was evaluated using gas chromatography–mass spectrometry (GC-MS) and ultra-high-performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry (UHPLC-Q-TOF-MS). Fifteen different volatile compounds were detected, with the primary compound identified as 1,6-dioxacyclododecane-7,12-dione, originating from the PBAT component. This compound, along with others, resulted from the polymerization of adipic acid, terephthalic acid, and butanediol, forming linear and cyclic PBAT oligomers. Migration experiments were conducted using three food simulants—95% ethanol, 10% ethanol, and 3% acetic acid—over a period of 10 days at 60 °C. No migration above the detection limits of the analytical methods was observed for 3% acetic acid and 10% ethanol. However, migration studies with 95% ethanol revealed the presence of new compounds formed through interactions between the simulant and PBAT monomers or oligomers, indicating the packaging’s sensitivity to high-polarity food simulants. Nevertheless, the levels of these migrated compounds remained below the regulatory migration limits. Full article

Starch films were obtained by solvent casting and thermoprocessing using glycerol as a plasticiser from a new starch source: tiger nut waste from horchata production. The tiger nut starch (TNS) films showed a barrier capacity to water vapour and gases in the typical range of other starch films, such as corn starch (CS) films, with a high barrier capacity to oxygen. The tensile properties of the films were affected by the processing method, exhibiting higher stiffness and resistance to break and lower stretchability than the more common CS films. Thermoprocessed TNS films were less water soluble than CS films, and their solubility was higher than that of cast TNS films. However, all films exhibited similar swelling power. Thermal stability was also similar for all TNS and CS films, showing the typical thermal degradation pattern of starch–glycerol films. Therefore, TNS obtained from horchata production waste can be used to obtain thermoplastic starch films for packaging applications, with characteristics comparable to the most common corn starch films. Full article

The world economy is struggling with the increasing pollution of the natural environment with non-biodegradable synthetic polymers produced from petroleum products. This fact has prompted research on the use of natural renewable polymers. Starch is one of the polymers that has already been used as an additive to synthetic polymers; however, its use is associated with a problem arising from the incompatibility of hydrophilic starch with hydrophobic synthetic polymers. For these reasons, other authors have not used more than 20% of the starch component in synthetic materials. In this work, a research hypothesis was put forward that the starch content can be increased in the polymer material. Pre-extrusion was used before the final material molding process. Pre-extrusion improved the phase dispersion of the synthetic polymer blended with starch. To produce the molds, the polyamide and starch blends were subjected to the processes of extrusion, milling, and pressing. The molded samples containing polyamide and starch were obtained with a starch component content of 50, 70, and 90%. The obtained homogeneous material was determined in terms of its water resistance and mechanical properties. The test results showed that increasing the starch content in the produced material, increased its susceptibility to water, and worsened its strength properties. However, these negative effects were not as large as expected, and in some cases were even statistically insignificant. The addition of 70% of the starch component allowed for the production of a composite material with satisfactory mechanical properties. Full article

The concern for the environment and sustainability has intensified the search for alternative materials to replace non-degradable plastics. Poly(butylene adipate-co-terephthalate) (PBAT) is a bioplastic that has been extensively studied due to its excellent mechanical properties, which are similar to those of low-density poly(ethylene) (LDPE). However, the high cost of this polymer still hinders its wider application. Among the different approaches that have been studied, blending PBAT with thermoplastic starch (TPS) could be an interesting solution to reduce the cost of the material and increase the degradability of the blends. This review covers most of the work reported in recent years on PBAT/TPS blends, including the effects of starch plasticizers, starch modifications, processing methods, use of chain extenders, various compatibilizers, and additives used for different applications. Full article

The immiscibility of thermoplastic starch (TPS) and polybutylene succinate (PBS) complicates the thermal processing of these materials. This study provides the first comparative assessment of two compatibilizers with differing reaction mechanisms, Joncryl^® ADR 4468 and epoxidized linseed oil (ELO), for the optimization of biobased TPS/PBS blends. A total of 13 batches, varying in compatibilizer and blend composition, were processed via hot melt extrusion and injection molding to produce pellets. Blends were analyzed using tensile and impact testing, differential scanning calorimetry (DSC), Fourier transform infrared spectroscopy (FTIR), rheology, and scanning electron microscopy (SEM). The findings suggest that both compatibilizers can improve the compatibility of these blends, as evidenced by higher glass transition temperatures (T_g) compared to the reference batch (100-0-N/A). Joncryl^® ADR 4468 batches exhibit superior tensile strength and Young’s moduli, while ELO batches demonstrate greater elongation at break. The enhanced processability observed in Joncryl^® ADR 4468 is attributed to the increased polymer chain entanglement and molecular weight, whereas ELO facilitates greater chain mobility due to its plasticizing effect. These differences arise from the distinct mechanisms of action: Joncryl^® ADR 4468 promotes chain extension and crosslinking, whereas ELO mainly enhances flexibility through plasticization. Overall, this study provides a comparative assessment of these compatibilizers in TPS/PBS blends, laying the groundwork for future investigations into optimizing compatibilizer concentration and blend composition. Full article

We modified native wheat starch using 15, 30, and 60 min of acid hydrolysis (AH). The non-modified and AH-modified starches were converted to highly homogeneous thermoplastic starches (TPSs) using our two-step preparation protocol consisting of solution casting and melt mixing. Our main objective was to verify if AH can decrease the processing temperature of TPS. All samples were characterized in detail by microscopic, spectroscopic, diffraction, thermomechanical, rheological, and micromechanical methods, including in situ measurements of torque and temperature during the final melt mixing step. The experimental results showed that (i) AH decreased the average molecular weight preferentially in the amorphous regions, (ii) the lower-viscosity matrix in the AH-treated starches resulted in slightly higher crystallinity, and (iii) all AH-modified TPSs with a less viscous amorphous phase and higher content of crystalline phase exhibited similar properties. The effect of the higher crystallinity predominated at a laboratory temperature and low deformations, resulting in slightly stiffer material. The effect of the lower viscosity dominated during the melt mixing, where the shorter molecules acted as a lubricant and decreased the in situ measured processing temperature. The AH-induced decrease in the processing temperature could be beneficial for energy savings and/or possible temperature-sensitive admixtures for TPS systems. Full article

Unlike the hot-melting processing of thermoplastic plastics, the processing of starch-based material relies on the addition of solvents, resulting in their low productivity, hindering large-scale industrialized production. A strategy to realize the high production efficiency of starch-based material, an environmentally friendly modification process without waste liquid generation, was designed to prepare a hot-melting starch (HMS) that can be repeatedly hot melted. Ball milling, enzymatic digestion, and deep eutectic solvent (DES) plasticization modification were combined to prepare the HMS. Ball milling destroyed the starch’s particles and the crystallinity, exposing the hydroxyl group, which allowed amylase to achieve enzymatic hydrolysis more easily. After enzymatic hydrolysis, the molecular chains of modified starch were shortened and the entanglement of molecular chains was reduced, which promoted the slip of molecular chains. The plasticization of DES, which promoted by the broken starch particles and the destroyed crystal structure, formed stronger hydrogen bonds and facilitated hot melting. Furthermore, due to the excellent hot-melting properties, HMS can be combined with sisal fiber and polycaprolactone (PCL) under solvent-free conditions. The tensile strength of HMS/sisal fiber/PCL was increased by 109%; meanwhile, the water contact angle was stabilized at 104°, when the blending ratio of hot-melting starch was 67.5% compared with HMS. Full article

In this study, the aerobic degradation of sweet potato (Ipomoea batatas; SP) and diamond yam (Dioscorea rotundata; DY) thermoplastic starch (TPS) blends, combined with polylactic acid (PLA) and varying ratios of citric acid (CA) as a crosslinker, was investigated in compost and seawater environments. After 50 d of composting, weight losses in the SP-TPS/CA/PLA blends were 56.9%, 52.3%, and 77.5%, while those of DY-TPS/CA/PLA were 55.8%, 52.2%, and 62.2% for 0%, 1%, and 5% CA, respectively. In seawater, the SP-TPS/CA/PLA blends showed weight losses of 52.9%, 46.8%, and 61.5%, and the DY-TPS/CA/PLA blends lost 35.2%, 32.1%, and 43.9% for the same CA ratios, respectively. In both media, SEM revealed structural damage, holes, cracks, and changes in coloration, reflecting microbial activity. Additionally, in compost and seawater, TGA results showed that PLA remained the predominant component after 50 d, as most of the degradation occurred on TPS due to its amorphous structure and higher hydrophilicity. In both media, the SP-TPS/CA5/PLA and DY-TPS/CA5/PLA blends exhibited faster degradation, whereas SP-TPS/CA1/PLA and DY-TPS/CA1/PLA displayed higher stability and lower disintegration. Additionally, all blends required over 50 d to degrade completely, as evidenced by the absence of a plateau phase in the biodegradability curves. Statistical analysis showed that, in seawater, the degradation behavior of the blends was similar to cellulose. However, the CA ratio had a greater impact on the compost degradation of the blends with SP-TPS than on DY-TPS. Therefore, the critical factors influencing the degradation of these blends are the starch source and the CA ratio. Full article

Lollipop sticks were developed with fully biobased materials made of different plantain by-products, using extrusion processing followed by hot compression molding. The thermoplastic matrix was constituted of flour and starch from plantain bunch pulp and plantain peel cake. At the same time, two types of reinforcement were used, one of them being yarn from the lignocellulosic fibers of the pseudostem sheaths to constitute the BC1 lollipop stick and the other directly from the plantain pseudostem treated sheath to establish the BC2 lollipop stick. The biobased lollipop sticks were characterized in the migration test, finding a higher structural stability in lipophilic foods, with chocolate chosen as a confection to undergo physicochemical, structural, mechanical, and dynamic–mechanical characterization when interacting with the two biobased lollipop sticks until post-consumption was reached. The BC2 lollipop stick was characterized by maintaining higher stability in maximum tensile strength (12.62 to 11.76 MPa), higher flexural strength (19.07 to 10.11 MPa), storage modulus (4.97 to 1.65 GPa at 30 °C), and Tan delta (66.90 to 52.64 °C). Full article

The effect of low-temperature plasma treatment on the surface properties of thermoplastic starch film (TPS) was investigated. The surface layer (SL) modification of polymeric materials is mainly carried out to improve wettability and adhesive properties and to increase surface cleanliness. TPS was modified in an air atmosphere under either atmospheric or reduced pressure. The process parameters for modifying the SL of TPS were determined based on wettability assessment using a goniometer, geometric structure using scanning electron microscopy (SEM), and the degree of oxidation (O/C ratio) using X-ray photoelectron spectroscopy (XPS). Additionally, the effect of plasma treatment on TPS film sterilization was investigated. Full article

This research developed a biodegradable absorbent pad using polybutylene adipate terephthalate (PBAT) and thermoplastic starch (TPS) films, combined with hairy basil (Ocimum basilicum) seed powder (HBP) to extend the shelf life of fresh pork during cold storage. To form the biocomposite film, PBAT was blended with TPS in ratios of 100:0, 90:10, 70:30, and 50:50. The PBAT:TPS ratio of 70:30 (PB7T3) was the most suitable in terms of mechanical properties and water permeation. Therefore, PB7T3 was selected to fabricate the absorbent pad for extending the shelf life of fresh pork during cold storage. For the storage test, 100 g of pork pieces was placed in PET trays (12 cm × 12 cm), each containing a different absorbent: the control (no pad), a commercial absorbent pad, and the PB7T3 absorbent pad. The pork samples were stored at 4 °C for 8 days and analyzed for color change, total plate count (TPC), total volatile basic nitrogen (TVB-N), pH, and drip loss on days 0, 2, 4, 6, and 8. The results indicated that the PB7T3 absorbent pad effectively extended the shelf life of fresh pork compared to the control, with no significant difference compared to the commercial absorbent pad made from plastic. This research opens new avenues for developing sustainable absorbent pads, contributing to reduced reliance on conventional non-biodegradable plastics. Full article

Obtaining active extracts from beet root leaves and stems (BLS) is an alternative for the valorization of this agricultural waste. Subcritical water extraction (SWE) at 150 °C and 170 °C has been used to obtain these extracts, which were incorporated (6% wt.) into polymer matrices to produce antioxidant films of thermoplastic starch (TPS) and polylactic acid (PLA) for the preservation of sunflower oil. A high extraction yield (67–60% solubilized solids) was achieved, and the extracts contained high levels of total phenols (51–73 mg GAE·g⁻¹ extract) and betalains and great radical scavenging capacity (EC₅₀: 30–22 mg mg⁻¹ DPPH). The highest temperature promoted the extract’s phenolic richness and antioxidant capacity. The TPS and PLA films containing extracts exhibited color and UV-light blocking effects. The extracts reduced the oxygen permeability (OP) and water vapor permeability of PLA films while promoting those of the TPS films. The capacity of the films to preserve sunflower oil from oxidation was mainly controlled by the OP values of the films, which were very high in TPS films with low OP values. However, in the PLA films (which were more permeable to oxygen), the antioxidant extracts provided significant protection against sunflower oil oxidation. Full article

The environmental impact of conventional plastics has spurred interest in biopolymers as sustainable alternatives, yet their performance under abiotic degradation conditions still remain unclear. This study investigated the effects of ultraviolet C (UV-C) irradiation and its combination with water immersion (UV-C/H₂O) on films of commercial poly(butylene adipate-co-terephthalate)-thermoplastic starch (PBAT/TPS) blends. Changes in structural, chemical, morphological, and thermal properties, as well as molar mass, were analyzed. The results showed distinct degradation mechanisms during exposure to UV-C irradiation either in dry or during water-immersion conditions. UV-C irradiation disrupted PBAT ester linkages, inducing photodegradation and chain scission, leading to a more pronounced molar mass decrease compared to that under water immersion, where a more restrained impact on the molar mass was ascribed to diffuse attenuation coefficient of irradiation. Nevertheless, under UV-C/H₂O conditions, erosion and disintegration were enhanced by dissolving and leaching of mainly the TPS fraction, creating a porous structure that facilitated the degradation of the film. Blends with higher TPS content exhibited greater susceptibility, with pronounced reductions in PBAT molar mass. In conclusion, exposure of films of PBAT/TPS blends to ultraviolet/water-assisted environments effectively initiated abiotic degradation, in which fragmentation was accentuated by the contribution of water immersion. Full article

As the demand for sustainable and environmentally friendly materials has increased, renewable resources have been explored for the development of biobased composites. Two biobased composite materials were developed from thermoplastic starch (TPS), short fibers from plantain pseudostems sheaths and the starch from the plantain pseudostem core, using twin-screw extrusion and compression molding. Based on the findings, there is evidence of a biobased composite material with reduced water absorption of up to 9.9%, keeping thermal stability at a degradation temperature between 300 and 306 °C and increasing tensile properties by over 506%, although hardness showed slight increases (4.6%). In addition, the capacity of the sheath to generate a water vapor barrier is highlighted by reducing the magnitude of losses in mechanical properties during storage for a period of 8 days. This study contributes to the use of agricultural residues to create sustainable products, offering a pathway toward reducing dependency on synthetic polymers and mitigating environmental impact. Full article

Thermoplastic starch (TPS) is one of the most-used biodegradable materials, alongside polylactide (PLA), and is a promising alternative to traditional plastics. However, unmodified TPS has processing limitations due to its mechanical properties and susceptibility to moisture. Modern TPS modifications often lead to the loss of its full biodegradability, which limits its contribution to reducing polymer waste and the circular economy. This article presents a novel TPS-based material enriched with micronized chalcedonite, which improves the mechanical properties of the composite while maintaining biodegradability. An assessment of processing in injection molding technology and tests of strength, hardness, impact strength, and water absorption depending on the filler content were carried out. The results obtained indicate that the use of chalcedonite not only strengthens the material structure but also contributes to reducing the demand for synthetic additives, which can reduce the amount of difficult-to-dispose polymer waste. The development of more durable and fully biodegradable materials based on TPS is a step towards sustainable development, enabling the reduction in plastic in the environment and supporting the idea of a circular economy. The research results open new perspectives for ecological composites that can be used in various industrial sectors, reducing the negative impact of plastics on the environment. Full article