The synthesis of block copolymers of glycidyl methacrylate (G), styrene (S) and acrylonitrile (AN) (represented as GS-SAN) by reversible addition–fragmentation chain transfer (RAFT) polymerization, with well-defined average molar masses and epoxy functionalities, and evaluation of their performance as macromolecular chain extenders for recycled poly(lactic acid) (rPLA), is reported. The introduction of the GS-SAN chain extenders during the extrusion processing of rPLA leads to recovery of molar mass as well improvement of thermal stability and rheological properties, compared to recycled unmodified PLA. Differential scanning calorimetry (DSC) results revealed a reduction in cold crystallization temperature and an increase in the degree of crystallinity of chain extended rPLA. Increasing epoxide content in the synthesized block copolymers leads to increased degrees of crystallinity. The rheological study revealed that the GS-SAN copolymers allowed significant increases in modulus, strength and complex viscosity of chain extended rPLA, indicating that better mechanical performance and processability were obtained. These increases become more pronounced as the concentration of reactive epoxy functional group is increased.

通过可逆的加成-断裂链转移（RAFT）聚合，合成甲基丙烯酸缩水甘油酯（G），苯乙烯（S）和丙烯腈（AN）的嵌段共聚物（具有明确的平均摩尔质量和环氧官能度）报道了其作为可回收的聚乳酸（rPLA）的大分子扩链剂的性能评估。与回收的未改性PLA相比，在rPLA的挤出加工过程中引入GS-SAN扩链剂可提高摩尔质量，并改善热稳定性和流变性。差示扫描量热法（DSC）结果表明，冷结晶温度降低，而扩链rPLA的结晶度增加。合成的嵌段共聚物中环氧化物含量的增加导致结晶度的增加。流变学研究表明，GS-SAN共聚物可显着提高链增长rPLA的模量，强度和复数粘度，表明获得了更好的机械性能和可加工性。随着反应性环氧官能团浓度的增加，这些增加变得更加明显。