ATRP法合成大分子单体及其在微球制备中的应用

Synthesis of macromonomer by atom transfer radical polymerization and its application to preparing polymeric microspheres

以α-溴代丙酸乙酯(EPN-Br)为引发剂,氯化亚铜(CuCl)与N,N,N′,N″,N″-五甲基二亚乙基三胺(PMDETA)组成的混合体系为催化剂,使甲基丙烯酸叔丁酯(tBMA)进行原子转移自由基聚合(ATRP),得到了端基为溴原子的聚甲基丙烯酸叔丁酯大分子中间体PtBMA-Br。使其末端的Br与甲基丙烯酸发生亲核取代反应,得到甲基丙烯酸封端的大分子单体。FTIR和1H-NMR的分析表明大分子单体结构明确,双键导入率高;再用该大分子单体与苯乙烯分散共聚制得形态规整的高分子微球。

Macro-intermediate with Br-end Poly（tert-butyl methacrylate） （PtBMA-Br） was synthesized by Atom Transfer Radical Polymerization （ATRP）, with ethyl-2-bromopropionate as initiator, a compound system of CuCl/N,N,N＇,N＂,N＂-penta-methyldiethylenetri-amine （PMDETA） as catalyst. Then hydrophobic macromonomers were synthesized through introducing C=C double bond to the end of poly（tert-butyl methacrylate） by nucleophilic substitution with methacrylic acid. The results of spectral methods （FTIR and ^1H-NMR） showed clearly defined structure of macromonomers and high introduction rate of C=C double bond. The molecular weight and polydispersity of the macromonomers were controllable because of the living nature of the atom transfer radical polymerization. Further, polymeric microspheres were prepared by dispersion copolymerization of macromonomers and styrene, with azo-bis-isobutyronitrile （AIBN） as initiator, ethanol as solvent. Scanning electron micrograph （SEM） showed regular shape of copolymeric microsheres.