This work sought to improve the toughness and thermal stability of poly(lactic acid) (PLA) by incorporating poly(butylene succinate) (PBS) and wood flour (WF). The PLA/PBS blends showed a PBS-dose-dependent increase in the impact strength, elongation at break, degree of crystallinity, and thermal stability compared to the PLA, but the tensile strength, Young's modulus, and flexural strength were all decreased with increasing PBS content. Based on the optimum impact strength and elongation at break, the 70/30 (w/w) PLA/ PBS blend was selected for preparing composites with five loadings of WF (5-30 phr). The impact strength, tensile strength, flexural strength, and thermal stability of the PLA/PBS/WF composites decreased with increasing WF content, and the degree of crystallinity was slightly increased compared to the 70/30 (w/w) PLA/PBS blend. Based on differential scanning calorimetry, the inclusion of PBS and WF into PLA did not significantly change the glass transition and melting temperatures of PLA in the PLA/PBS blends and PLA/ PBS/WF composites. From the observed cold crystallization temperature of PLA in the samples, it was evident that the degree of crystallinity of PLA in all the blends and composites was higher than that of PLA.

This study aimed to improve the brittleness and thermal stability of poly(lactic acid) (PLA) by inclusion of poly(butylene succinate) (PBS) and microcrystalline cellulose (MCC). Of the three PLA/PBS blends (10, 30 and 50 wt% PBS) evaluated, the 70/30 wt% blend exhibited the highest impact strength and elongation at break, but a lower thermal stability compared to that of the pure PLA. Scanning electron microscopy analysis confirmed the better compatibility of this 70/30 PLA/PBS blend. This blend was further filled with MCC. Based on thermogravimetric analysis, the thermal stability of the 70/30 PLA/PBS blend was improved by the addition of MCC [optimal at five parts by weight per hundred (phr)] and further still by the addition of the chain extender, Joncryl TM , at 0.5 phr. The 70/30/5/0.5 PLA/PBS/MCC/Joncryl TM composite exhibited the highest impact strength, while the elongation at break was acceptable.

No abstract

Poly(lactic acid) (PLA) was first melt blended with five weight percentages (10-50 wt %) of poly(butylene adipate-coterephthalate) (PBAT) on a twin-screw extruder and then injection molded. The blend at 30 wt % PBAT exhibited the highest impact strength and elongation-at-break without phase inversion. The 70/30 (w/w) PLA/PBAT blend with high toughness improvement was selected for preparing both single and hybrid composites using an organic filler, wood fiber (WF) and inorganic filler, wollastonite (WT) with a fix total loading at 30 parts per hundred of resin (phr) throughout the experiment. Five WF/WT (phr/phr) ratios for the composites were 30/0, 10/20, 15/15, 20/10, and 0/30. The prepared composites were investigated for the mechanical and thermal properties, melt flow index (MFI), morphology, flammability, water uptake, and biodegradability as a function of composition. All the composites showed a filler-dose-dependent decrease in the impact strength, elongation-at-break, MFI, and thermal stability, but an increase in the tensile and flexural modulus, tensile and flexural strength, antidripping ability, and water uptake compared with the neat blend. The addition of WF and WT was also found to promote the biodegradability of the PLA/PBAT blend.

This study reported the use of tetrabenzylthiuram disulphide (TBzTD) as a noncarcinogenic accelerator in a traditional sulfur curing system of epoxidized natural rubber (ENR)/nanosilica (nSiO 2 ) composites. ENR used in this work was synthesized via in situ epoxidation of natural rubber (NR) in the presence of performic acid generated from the reaction of formic acid and hydrogen peroxide at 50 ∘ C for 8 h to acquire the epoxide content of about 40 mol%. Accordingly, the resulting ENR was referred to as ENR 40. The curing characteristics, mechanical properties, thermal behaviors, dynamic mechanical properties, and oil resistance of ENR 40/nSiO 2 nanocomposites filled with three loadings of nSiO 2 (1, 2, and 3 parts per hundred parts of rubber) were investigated and compared with NR and neat ENR 40. The results revealed that the scorch and cure times of ENR 40/nSiO 2 nanocomposites were slightly longer than those of NR but slightly shorter than those of ENR 40. The tensile properties and tear strength for both before and after aging of all ENR 40/nSiO 2 nanocomposites were higher than those of ENR 40, while the glass transition temperature, storage modulus at −65 ∘ C, thermal stability, and oil resistance of ENR 40/nSiO 2 nanocomposites were higher than those of NR and ENR 40.