可逆加成-断裂-链转移法制备偏光用聚乙烯醇与偏光膜的性能  

Preparation of Polyvinyl Alcohol for Optical by RAFT and Properties of Polarizing Film

作　　者：覃忠琼 徐文总 胡源[1] 刘亚琳 宋磊[1] Zhongqiong Qin;Wenzong Xu;Yuan Hu;Yalin Liu;Lei Song(State Key Laboratory of Fire Science,University of Science and Technology of China,Hefei 230026,China;School of Materials Science and Chemical Engineering,Anhui Jianzhu University,Anhui Province International Research Center on Advanced Building Materials,Hefei 230601,China)

机构地区：[1]中国科学技术大学火灾国家重点实验室,安徽合肥230026 [2]安徽省先进建筑材料国际联合研究中心安徽建筑大学材料与化学工程学院,安徽合肥230601

出　　处：《高分子材料科学与工程》2022年第4期20-28,共9页Polymer Materials Science & Engineering

基　　金：国家自然科学基金重大项目(51991352);安徽省高校协同创新项目(GXXT-2019-001);安徽省先进建筑材料国际联合研究中心主任基金(JZCL015ZZ)。

摘　　要：以黄原酸酯/过氧化苯甲酰(BPO)为引发体系引发醋酸乙烯酯(VAc)自由基可逆加成-断裂-链转移(RAFT)溶液聚合制备聚醋酸乙烯酯(PVAc),醇解后制得聚乙烯醇(S-RAFT)。利用凝胶渗透色谱测其相对分子质量及其分布。通过核磁共振氢谱研究S-RAFT的立构规整度,使用分光光度计研究聚乙烯醇(PVA)的聚集态。通过与6种不同PVA原料以及3种市售偏光基膜的立构规整度和聚集态比较,发现S-RAFT与市售光学基膜的PVA原料的立构规整度相似,间同等规立构(rr)含量和结晶度普遍比PVA原料高。比较S-RAFT其他PVA原料及市售基膜制成的偏光膜性能后发现,S-RAFT的成膜性好、偏光度高,具有较高的拉伸模量,有望成为制备高端偏光片的原料。另外,通过与VAc传统自由基聚合醇解产物(S-FRP)对比,详细推导以黄原酸酯为链转移剂的RAFT制备高间同结构PVA的过程,提出了黄原酸酯的“顺式热分解”机理。A xanthate/BPO initiator system was used to initiate the reversible addition-fragmentation-chain transfer(RAFT)solution polymerization of vinyl acetate to prepare polyvinyl acetate(PVAc).By alcoholysis of PVAc,polyvinyl alcohol(PVA:S-RAFT)was produced.Gel permeation chromatography(GPC)was hired to analyze the molecular weight and distribution of the samples.1H-NMR was used to study the tacticity of PVA.The aggregation state of PVA was investigated by FT-IR.By comparing the tacticity and aggregation state of 6 different PVA raw materials and 3 commercial polarizing base films,it is found that the tacticity of S-RAFT and the optical base film are similar,the content of syndiotacticity(rr)and crystallinity are higher than those of PVA raw material.After comparing the properties of polarizing films made of S-RAFT,PVA raw materials and commercial base films,it is found that S-RAFT has good film forming properties,high degree of polarization,and high tensile modulus.It is expected to be a raw material for the preparation of high-end polarizers.In addition,by comparing with the structure of PVA with traditional free radical polymerization alcoholysis,the process of preparing high syndiotactic PVA by RAFT using xanthate as chain transfer agent was deduced in detail.A novel"cis fragmentation"mechanism of xanthate was proposed.

关 键 词：可逆加成-断裂-链转移 聚乙烯醇 立构规整度 偏光膜性能 顺式热分解 

分 类 号：TQ325.9[化学工程—合成树脂塑料工业]