特殊形态接枝高分子颗粒的合成

表面接枝高分子微球具有分子结构的可设计性 ,分散稳定性好 ,被用于高效催化剂的载体、药物释放控制和疾病治疗等生物医学领域 ,因而引起了许多高分子材料和生物医学工作者的极大兴趣[1～ 3] .我们用链转移自由基聚合法合成了一端为苯乙烯基封端的聚乙二醇 ( PEG)和聚 ( N -异丙基丙烯酰胺 )等亲水性大分子单体 .在与疏水性单体如苯乙烯等的二元分散共聚反应中 ,利用接枝共聚物在溶液中的自组装 ,制备了粒径分布均一 ,颗粒表面形态光滑 ,同时表面具有功能性高分子链的微球 [4～ 8] .传统的合成高分子微球的研究主要是以苯乙烯或甲基丙烯酸…

Synthesis of Grafted Polymer Particles with Unusual Form

PEG macromonomer having one methacryloyl end group for per polymer chain was selected as reaction stabilizer. The distribution of molecular weight of the macromonomer was less than 1.1 based on the GPC analysis. Poly(acrylonitrile/styrene) particles with sub-micron sizes were prepared by dispersion copolymerization of acrylonitrile with styrene by using 2,2'-azobisisobutyronitrile(AIBN) as a free radical initiator in the presence of PEG macromonomer in V(ethanol)∶V(water)=7∶3 mixed solvents at 60 ℃ for 24 h. The particles having narrow size-distribution were obtained and studied by transmission electron microscopy(TEM) and laser light scattering(LLS). The surfaces of the particles have unusual structures(strawberry form or wheel form shows) which can be control by changing molecular weight of PEG macromonomer and other reaction conditions. The structure of the freeze-dried particles was investigated by X-ray diffraction(XRD) system and showed a distinct diffraction peak at 2θ=22.6°, indicating that the particles are crystallized.