Mechanical Enhancement of Biodegradable Poly(Butylene Succinate) by Biobased Polyamide11

Biodegradable poly(butylene succinate) (PBS) was melt blended with biobased polyamide11, which an epoxy-based chain extender, Joncryl ADR-4300, was added to improve the blend compatibility. Mechanical properties of the blends were evaluated by tensile and impact testing. The blends were characterized by Fourier transform infrared spectroscopy, Differential scanning calorimetry and Thermogravimetric analysis. Morphology was investigated by Scanning electron microscopy. It was found that morphology of the immiscible blends with polyamide11 less than 50 wt% was a sea-island structure. Adding the chain extender confirmed better chemical compatibility in the blends evident by smaller dispersed domain sizes and less pullout. The blends with higher polyamide11 content increased Young's modulus following the rule of mixture, however, the rigidity was reduced when adding the chain extender. It was interesting to observe that impact strength of the blends with polyamide11 content higher than 30 wt% was enhanced significantly with the presence of chain extender, although tensile strength and elongation at break were reduced. The crystallization temperature of PBS increased with higher polyamide11 content due to the nucleation effect, although the degree of crystallinity was in the same range. The thermal degradation temperature of the blend was shifted to higher temperature confirming the chain extension reaction occurred.