扩链剂对PBAT/TPS共混体系性能的影响

Effect of Chain Extender on Properties of PBAT/TPS Blends

将聚对苯二甲酸-己二酸-丁二醇酯(PBAT)与热塑性淀粉(TPS)共混,可以降低材料的成本并改善加工性能,但二者相容性较差。以Joncryl型扩链剂(ADR)为增容剂,制备PBAT/TPS/ADR共混物并吹塑成膜,研究ADR含量对共混体系的分子量、热学性能、结晶行为、拉伸性能和光学性能的影响。结果表明:ADR中环氧基团能够与PBAT和TPS的化学键结合,提高共混物的分子链长度。适量的ADR降低分子链的运动能力和排列有序性,从而降低PBAT的结晶度。ADR的加入能够改善PBAT与TPS的相界面,提升薄膜的拉伸强度与断裂伸长率,降低薄膜的总雾度。当ADR的含量为1%,薄膜的拉伸性能最好,纵向(MD)拉伸强度提升至20.3 MPa,断裂伸长率提升至672%。但当ADR的含量超过1%,共混物的分子链断裂,导致薄膜的拉伸性能下降。

Blending Poly(butylene adipate-co-terephthalate)(PBAT) with thermoplastic starch(TPS) can reduce the cost of materials and improve the processing performance, but the poor compatibility between two requires modification. PBAT/TPS/ADR blends were prepared by twin-screw extruder with Joncryl chain extender(ADR) as compatibilizer and blown film was formed. The effects of ADR content on molecular weight, thermal properties, crystallization behavior, tensile properties and optical properties of the blends were studied. The results show that the epoxy group in ADR can combine with chemical bonds of PBAT and TPS to improve molecular chain length of blends. An appropriate amount of ADR reduces the mobility and ordering of molecular chains, and reduces the crystallinity of PBAT. The addition of ADR can improve phase interface between PBAT and TPS, improve the tensile strength and elongation at break of film, and reduce the total haze of film. When the content of ADR is 1%, the film has the best tensile properties, the longitudinal(MD) tensile strength increases to 20.3 MPa, and the elongation at break increases to 672%. However, when the content of ADR exceeds1%, the molecular chain of blend breaks, resulting in decrease of the tensile properties of film.