RAFT聚合法合成苯乙烯/乙烯水杨醛嵌段共聚物及其自组装  

Synthesis of PS-b-PHVB Block Copolymer via RAFT Polymerization and its Self-assembly Behavior

作　　者：何强芳[1] He Qiangfang(College of Chemistry and Materials Science,Guangdong University of Education,Guangzhou 510303,China)

机构地区：[1]广东第二师范学院化学与材料科学学院,广东广州510303

出　　处：《广东化工》2023年第16期9-11,21,共4页Guangdong Chemical Industry

基　　金：广东第二师范学院教学质量与教学改革工程(2019jxgg12);广东省自然科学基金(2015A030310228)。

摘　　要：以末端含有三硫酯结构的聚苯乙烯(PS-DMAT)为大分子链转移剂,AIBN为引发剂,在65℃下四氢呋喃(THF)中成功实现了苯乙烯(St)与乙烯基水杨醛(HVB)的“活性”/可控RAFT自由基嵌段共聚合。通过凝胶渗透色谱(GPC)对产物的分子量进行了分析,结果表明合成聚合物数的均分子量(Mn)基本上随乙烯基水杨醛(HVB)单体转化率的增加而线性地增加,在整个反应过程聚合物均保持较窄的的分子量分布(Mw/Mn<1.30),聚合过程呈现出自由基共聚合可控特征。利用核磁共振氢谱(1HNMR)对嵌段共聚物聚苯乙烯-b-聚乙烯水杨醛(PS-b-PHVB,Mn=15300,Mw/Mn=1.18)进行了表征,确定了其结构及组成。此外,通过动态光散射仪(DLS)和扫描电子显微镜(SEM)研究了嵌段共聚物在四氢呋喃(THF,共溶剂)和乙醇(EtOH,选择性溶剂)的混合溶剂中的自组装行为,结果表明,当THF/EtOH体积比为4/6、5/5、6/4时,嵌段聚合物能够形成形状规则、平均粒径在200~300 nm左右的球形胶束。A well-defifined block copolymer polystyrene-block-poly(2-hydroxy-5-vinylbenzal-dehyde)(PS-b-PHVB)was synthesized by reversible addition–fragmentation chain transfer(RAFT)polymerization of HVB monomer using a polystyrene-terminated trithiocarbonate as macro-chain transfer agent.The trithiocarbonate terminated polystyrene was first prepared under stander RAFT conditions employing S-1-dodecyl-S΄-(α,α´-dimethyl-α´´-acetic acid)trithiocarbonate(DMAT)as the RAFT agent in conjunction with 2,2’-azobisisobutyronitrile(AIBN)at 110℃in bulk.The obtained PS macro-RAFT agent was then allowed to react with HVB in the presence of AIBN in tetrahydrofuran(THF)at 65℃to produce well-defined block copolymers PS-b-PHVB.Gel permeation chromatography(GPC)analysis,calibrated with linear polystyrene standards,indicated the number-average molecular weight of the obtained block copolymers increased linearly with monomer conversion,and the molecular weight distribution was narrow(Mw/Mn<1.30),although they became slightly broader as the polymerization proceeded.These results indicated the RAFT polymerization of HVB mediated with PS macro-RAFT agent proceeded in a controlled manner.The structure and composition of a representative sample block copolymer PS-b-PHVB(Mn=15300,M w/Mn=1.18)was verified by 1HNMR spectroscopy.The self-assembling behavior of representative sample block copolymer PS-b-PHVB was studied in a mixture solvent of THF(as a common solvent)and ethanol(EtOH)(as a selective solvent)and was determined by Dynamic light scattering(DLS)Scanning electron microscopy(SEM).The results showed that spherical micelles were formed at common solvent THF and selective solvent EtOH ratio of V(THF)∶V(EtOH)=4∶6,5∶5 and 6∶4 with mean diameter of about 200~300 nm.

关 键 词：乙烯基水杨醛 可逆加成-断裂链转移聚合 嵌段共聚物 自组装 胶束 

分 类 号：TQ[化学工程]