可逆加成-断裂链转移细乳液聚合法制备木质素基嵌段共聚物

Synthesis of Lignin-Based Block Copolymer by RAFT Miniemulsion Polymerization

以木质素黄原酸酯为链转移剂,进行丙烯酰胺(AM)的可逆加成-断裂链转移(RAFT)自由基聚合,并将得到的木质素-丙烯酰胺接枝共聚物(Lignin-g-PAM)作为大分子链转移剂,加入第二单体甲基丙烯酸甲酯(MMA)进行扩链反应制备木质素基嵌段共聚物(Lignin-g-PAM-b-PMMA)。红外光谱、核磁共振氢谱、凝胶渗透色谱、差示扫描量热及热重分析结果证实了MMA与Lignin-g-PAM反应形成了嵌段共聚物;所得Lignin-g-PAM-b-PMMA的相对分子质量显著增加,相对分子质量分布变宽,初始分解温度及最大质量损失温度提高,玻璃化转变温度介于Lignin-g-PAM与PMMA的玻璃化转变温度之间。

Lignin xanthate was used as chain transfer agent for the reversible addition-fragmentation chain transfer(RAFT)polymerization of acrylamide(AM).The lignin-g-PAM-CTA was employed for the preparation of lignin-g-PAM-b-PMMA block copolymer by adding the second monomer methyl methacrylate(MMA).The successful formation of block copolymers was confirmed by FT-IR,~1H-NMR,GPC,DSC and TGA.The lignin-g-PAM-b-PMMA block copolymer possesses a higher molecular weight and a wider molecular weight distribution.The temperature of the initial decomposition or maximum mass loss for the lignin-gPAM-b-PMMA block copolymer is significantly increased,while the glass transition temperature exists between that of lignin-g-PAM and PMMA.