辐照诱导长支链聚乳酸的流变性能

Rheological Behavior of Long-chain Branching Poly(lactic acid)Prepared via Electron Beam Irradiation

采用电子束辐照诱导法改性线形大分子结构的聚乳酸(PLA),使其发生断链和支化。采用动态剪切流变方法研究了辐照改性 PLA 的剪切流变行为。辐照改性制备的支化 PLA 具有较好的熔体黏弹性,在低频端剪切储能模量 G′明显提高,内耗正切 tan δ变小。讨论了 PLA 大分子旋光性、丙烯酸酯类双官能度单体(BDDA)用量和辐照剂量对 PLA 剪切流变行为的影响。实验发现,左旋聚乳酸(PLLA)比消旋聚乳酸对电子束更为敏感,更容易支化,并且在辐照剂量为1 kGy 时,其熔体弹性随 BDDA 用量的增加而增加;BDDA 用量为3份的 PLLA 时,熔体弹性随辐照剂量增加而增加。

Long-chain branching poly （lactic acid） （PLA） was prepared via electron beam irradiation of linear PLA, whose rheological behavior was characterized using dynamic shear testing. At low-frequency region, the long-chain branching PLA exhibited higher elastic shear modulus G＇ and lower loss angle tangent tan 9 than the corresponding linear one. The melt strength increased with increasing content of bifunctional monomer （BDDA） and/or radiation dose. It also found that poly （L-lactic acid） （PLLA） was more sensitive to electron beam than poly （D-lactic acid） （PDLLA）.