Poly(lactic acid) (PLA)/poly(butylene adipate-co-terephthalate) (PBAT) blends and their composite were prepared by melt compounding. Maleic anhydride grafted PLA (PLA-g-MA) was used as a compatibilizer. With the addition of PBAT into PLA, elongation at break and impact strength increased but tensile strength and modulus decreased. Incorporating PLA-g-MA into PLA/PBAT blend improved the mechanical properties of the blend. Tensile properties of blown film prepared from the compatibilized PLA/PBAT blend were better than those of the uncompatibilized PLA/PBAT blend. Incorporating CaCO₃ resulted in increased tensile strength and modulus of the film prepared from the compatibilized blend.

In this study, properties of natural rubber (NR) were enhanced by adding sisal fiber, which is a tropical plant in Thailand. Sisal fiber/natural rubber composites were prepared by the incorporation of sisal fiber at various loadings into natural rubber. Natural rubber grafted with maleic anhydride (NR-g-MA) prepared in house and epoxidized natural rubber (ENR50) were used to enhance the compatibility between sisal fiber and natural rubber. With increasing fiber loading, tear strength and hardness of natural rubber composites increased while their scorch time, cure time, tensile strength, and elongation at break decreased. Moreover, interfacial adhesion between sisal fiber and natural rubber was enhanced with the addition of NR-g-MA and ENR50. In comparison, NR-g-MA provided more effective improvement in mechanical properties of natural rubber composites than ENR50. For NR-g-MA compatibilized natural rubber composite at fiber loading of 10 phr, its tensile strength, modulus at 100% strain, modulus at 300% strain, tear strength, and hardness were increased 43, 44, 53, 42, and 13%, respectively, comparing with that of uncompatibilized natural rubber composite.

Poly(lactic acid) (PLA)/poly(butylene adipate-co-terephthalate) (PBAT) blends were prepared using melt processing. The effects of maleic anhydride grafted PLA (PLA-g-MA) and calcium carbonate (CaCO₃) content on mechanical, thermal, and morphological properties of the blends were investigated. PLA-g-MA was synthesized by varying monomer and initiator contents using a reactive melt-grafting process. Tensile properties of PLA/PBAT blend were enhanced with adding 2 phr of PLA-g-MA. SEM micrographs exhibited the improvement of interfacial adhesion between PLA and PBAT in the compatibilized blend. Moreover, thermal stability of the blends improved with presence of PLA-g-MA. With increasing CaCO₃ content, Young’s modulus of the composites increased.

Bamboo leaf fiber (BLF) was incorporated into an eco-friendly foam cushion made from natural rubber latex (NRL) to enhance the biodegradation rate. The objective of this work was to investigate the effects of BLF content on the foam structure, mechanical properties, cushion performance, and biodegradability. The NRL foam cushion nets with and without BLF were prepared using the Dunlop method along with microwave-assisted vulcanization. BLF (90–106 µm in length) at various loadings (0.00, 2.50, 5.00, 7.50, and 10.00 phr) were introduced to the latex compounds before gelling and vulcanizing steps. Scanning electron microscopy (SEM) showed that the BLF in a NRL foam caused an increase in cell size and a decrease in the number of cells. The changes in the cell structure and number of cells resulted in increases in the bulk density, hardness, compression set, compressive strength, and cushion coefficient. A soil burial test of 24 weeks revealed faster weight loss of 1.8 times when the BLF content was 10.00 phr as compared to the NRL foam without BLF. The findings of this work suggest the possibility of developing an eco-friendly cushion with a faster degradation rate while maintaining cushion performance, which could be a better alternative for sustainable packaging in the future.

This work aims to enhance the polarity of natural rubber by grafting copolymers onto deproteinized natural rubber (DPNR) to improve its compatibility with silica. Poly(acrylic acid-co-acrylamide)-grafted DPNR ((PAA-co-PAM)-DPNR) was successfully prepared by graft copolymerization with acrylic acid and acrylamide in the latex stage, as confirmed by FTIR. The optimum conditions to obtain the highest conversion, grafting efficiency, and grafting percentage were a reaction time of 360 min, a reaction temperature of 50 °C, and an initiator concentration of 1.0 phr. The monomer conversion, grafting efficiency, and grafting percentage were 91.9–94.1, 20.8–38.9, and 2.1–9.9%, respectively, depending on the monomer content. It was shown that the polarity of the natural rubber increased after grafting. The (PAA-co-PAM)-DPNR was then mixed with silica to prepare DPNR/silica composites. The presence of the (PAA-co-PAM)-DPNR and silica in the composites was found to improve the mechanical properties of the DPNR. The incorporation of 10 phr of silica into the (PAA-co-PAM)-DPNR with 10 phr monomer increased its tensile strength by 1.55 times when compared to 10 phr of silica loaded into the DPNR. The silica-filled (PAA-co-PAM)-DPNR provided s higher storage modulus, higher Tg, and a lower tan δ peak, indicating stronger modified DPNR/silica interactions and greater thermal stability when compared to silica-filled DPNR.