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首页> 外文期刊>Journal of Polymers and the Environment >Biodegradable Poly(lactic acid) Blends with Chemically Modified Polyhydroxyoctanoate Through Chain Extension
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Biodegradable Poly(lactic acid) Blends with Chemically Modified Polyhydroxyoctanoate Through Chain Extension

机译：可生物降解的聚乳酸与化学改性的聚羟基辛酸酯的扩链混合物

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摘要

Poly(lactic acid) (PLA) was blended with chemically modified Polyhydroxyoctanoate (mPHO) using a Haake twin-screw mixer. Due to the melt viscosity disparity between the two components, PHO was reacted with Hexamethylene diisocyanate (HDI) used as a chain extender to produce high molecular weight for improving compatibility and processability with PLA. The number average and weight average molecular weight of the PHO, reacted with 0.55 wt% HDI, were increased 314 and 275%, respectively, compared with those of the unmodified PHO. The blends were characterized for rheological, thermal, and mechanical properties. Infrared spectra confirmed the formation of the urethane linkages in mPHO. The shear viscosity, as a function of shear rate or shear stress, decreased with an increase in mPHO content, indicating that the PLA/ mPHO blends show shear-thinning behavior along with the power-law model. DSC thermograms showed that the two components in the blends were found with two crystalline phases and two amorphous phases confirming the coexistence of two immiscible components. Tensile results indicated that tensile strength for blends decreased with increasing mPHO content up to 80%. A decrease in elastic modulus, as well as an increase in elongation at break, was seen as a function of mPHO content. Results of aging tests showed that the mechanical properties of the blends also dropped more at a higher PLA level when compared with those of the unaged samples.
机译：使用Haake双螺杆混合器将聚乳酸（PLA）与化学改性的聚羟基辛酸酯（mPHO）混合。由于两种组分之间的熔体粘度差异，PHO与用作扩链剂的六亚甲基二异氰酸酯（HDI）反应生成高分子量，以改善与PLA的相容性和可加工性。与未改性的PHO相比，与0.55 wt％的HDI反应的PHO的数均和重均分子量分别增加了314和275％。共混物具有流变，热和机械性能。红外光谱证实了mPHO中氨基甲酸酯键的形成。剪切粘度随剪切速率或剪切应力的变化随mPHO含量的增加而降低，表明PLA / mPHO共混物与幂律模型一起表现出剪切稀化行为。 DSC热分析图显示，共混物中的两种组分具有两个结晶相和两个非晶相，这证实了两种不混溶组分的共存。拉伸结果表明，共混物的拉伸强度随着mPHO含量的增加而降低，最高可达80％。弹性模量的降低以及断裂伸长率的提高被视为mPHO含量的函数。老化测试的结果表明，与未老化样品相比，在较高的PLA含量下，共混物的机械性能也下降了更多。

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