原位法合成聚乳酸接枝淀粉共聚物的研究与应用

Investigation and Application of In-situ Synthesized Polylactic Acid Grafting Starch Copolymer

首次采用阴离子开环聚合的方法,在淀粉上一步法原位接枝聚合得到聚乳酸和淀粉的接枝共聚物。采用强极性溶剂二甲基亚砜(DMSO)将淀粉溶解,然后以叔丁醇钾为引发剂,引发L-丙交酯接枝聚合,提纯后的接枝产物通过红外光谱、核磁共振、XRD等测试方法进行表征。结果表明,在聚合温度为75℃,时间为4 h,淀粉/丙交酯/叔丁醇钾为10/75/3条件下,接枝产物的接枝率可达83%。将该接枝产物添加到淀粉和聚乳酸共混体系中,与未添加接枝物的共混体系相比,添加接枝物的共混体系中淀粉的分布更加均匀,性能更加均一。

Polylactic acid was in situ grafted onto starch via anionic ring opening polymerization. Starch was first dissolved in dimethyl sulfoxide, in which ring opening grafting of lactide was initiated by potassium text-butoxide. The product was characterized using FT-IR, NMR, and XRD. It was found that the optimal copolymerization temperature and time were 75 ℃ and 4 h. When the weight ratios of starch/lactide/potassium text-butoxide were 10/75/3, a graft efficiency of 83 % was obtained. Introducing the prepared graft copolymer into blends of starch/PLA, better dispersion of starch in PLA was observed.