原子转移自由基聚合法合成双亲性无规共聚物聚(苯乙烯-co-丙烯酸)及其自组装行为的研究

Synthesis of Amphiphilic Random Copolymers Poly(Styrene-co-Acrylic Acid)by Atom Transfer Radical Polymerization and Their Self-Assembly

通过原子转移自由基聚合,合成了一系列不同单体配比的无规共聚物 P(St-co-tBA)(St 为苯乙烯,tBA 为丙烯酸叔丁酯);以三氟乙酸为催化剂,P(St-co-tBA)水解得到无规共聚物 P(St-co-AA)(AA 为丙烯酸);用红外光谱、核磁共振、凝胶渗透色谱和示差扫描量热等方法对 P(St-co-AA)进行了表征;研究了 P(St-co-AA)在选择性溶剂中的自组装行为,用紫外-可见分光光度计、激光光散射仪、激光粒度分析仪和透射电子显微镜等对 P(St-co-AA)的自组装胶束进行了表征。实验结果表明,临界聚集水含量随 P(St-co-AA)中 AA 含量的增加而增大,随 P(St-co-AA)溶液初始质量浓度的减小而增大;P(St-co-AA)胶束粒径随 AA 含量的增加而减小,随 P(St-co-AA)溶液中水含量的减小而减小。初步探讨了聚合方法对 P(St-co-AA)自组装胶束化的影响,由原子转移自由基聚合得到的 P(St-co-AA)的胶束粒径(250 nm)比普通自由基聚合得到的P(St-co-AA)的胶束粒径(150 nm)大。

A series of random copolymers, poly（ styrene-co-tea-butyl acrylate） （P（St-co-tBA） ）, with different monomer ratios were synthesized by atom transfer radical polymerization （ATRP）. Random copolymers P（St-co-AA） （where AA is acrylic acid） were obtained by hydrolyzing of P（St-co-tBA） with trifluoroacetic acid as catalyst. The copolymers were characterized by means of FTIR, 1^H NMR, GPC and DSC. Self-assembly behavior of P（St-co-AA） miceUes in selective solvent was characterized by means of UV, LLS, laser granularity analyzer and TEM. The results shows that critical water content of P（ St-co- AA） solution rises correspondingly with increase of AA content and with reducing of initial concentration of P （St-co-AA） solution; the size of P （St-co-AA） micelles reduces correspondingly with increase of AA content and with reducing of water content in P （St-co-AA） solution. Effect of polymerization methods on self-assembly behavior was studied. The micelles diameters of P （ St-co- AA） synthesized by ATRP and common radical polymerization were 250 nm and 150 nm respectively.