Reactive extrusion using dicumyl peroxide (DCP) and a tri-functional coagent, triallyl trimesate (TAM) is implemented to introduce long-chain branching (LCB) in poly(lactic acid) (PLA). The effects of this modification on the long-term hydrolysis of PLA are assessed by monitoring the mass, molar mass distributions, and thermal properties of specimens exposed to hydrolytic degradation at a temperature of 60 °C. A slow initial rate of mass loss coupled with an immediate and rapid loss in molar mass are characteristic of a bulk erosion mechanism. Significant loss is observed in all molar mass averages within the first 20 days. In LCB PLA the most drastic decrease was observed in the z-average molar mass, M_z, as a result of the cleavage of the LCB segments from the polymer chain. Degradation induced crystallinity is observed in all formulations, attributed to the combined influence of annealing and the plasticizing effect of water. Although the hydrolysis profile is altered, reactive modification does not affect negatively the degradability of LCB PLA over a 12-week period, suggesting that these modified PLAs can be used in commodity applications that require degradable polymers.

使用过氧化二枯基（DCP）和三官能助剂三烯丙基三苯甲酸酯（TAM）进行反应挤出，以在聚乳酸（PLA）中引入长链支化（LCB）。通过监测60°C时发生水解降解的样品的质量，摩尔质量分布和热性质，可以评估这种改性对PLA长期水解的影响。缓慢的初始质量损失速率与摩尔质量中的立即和快速损失相结合是整体腐蚀机理的特征。在开始的20天内，所有摩尔质量平均值均观察到了明显的损失。在LCB PLA中，观察到z平均摩尔质量M _z急剧下降由于LCB链段从聚合物链上裂解而来。在所有配方中均观察到降解引起的结晶度，这归因于退火和水的增塑作用的综合影响。尽管水解特性发生了变化，但反应性改性不会在12周内负面影响LCB PLA的降解性，这表明这些改性的PLA可用于需要可降解聚合物的商品应用中。