Effect of Branching on Polymer Diffusion in Branched Poly(butyl methacrylate) Latex Films
Effect of Branching on Polymer Diffusion in Branched Poly(butyl methacrylate) Latex Films
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DOI：
10.1021/ma801526b
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发表时间：
2008-11
期刊：
影响因子：
5.5
通讯作者：
Yuanqin Liu;W. Schroeder;Jeffrey C. Haley;W. Lau;M. Winnik
中科院分区：
文献类型：
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作者：
Yuanqin Liu;W. Schroeder;Jeffrey C. Haley;W. Lau;M. Winnik
采用半连续乳液聚合法制备了支化聚甲基丙烯酸丁酯(PBMA)的给体和受体标记的荧光胶乳粒子。所有乳胶粒子具有相似的粒子大小和窄的粒度分布。通过加入不同量的双酚A二甲基丙烯酸酯(BPDM)作为支化剂来控制PBMA样品的支化度。采用1-十二硫醇(C12-−-SH)作为链转移剂，防止凝胶形成，控制相对分子质量。所有PBMA样品的数均相对分子质量约为45000g/mol。用核磁共振氢谱测定了其支化度。乳胶膜是从1：1的供体和受体标记的胶乳混合物中浇注而成。利用时间相关单光子计数技术测量了聚合物在乳胶膜中的能量传递，研究了聚合物在乳胶膜中的扩散行为。乳胶膜在23℃热处理后，聚合物扩散速率随玻璃化转变温度的降低而增加。
Fluorescent donor- and acceptor- labeled latex particles comprised of branched poly(butyl methacrylate) (PBMA) were prepared via semicontinuous emulsion polymerization. All latex particles have similar particle size and narrow size distribution. The degrees of branching of the PBMA samples were controlled by adding various amount of bisphenol A dimethacrylate (BPDM) as a branching agent. 1-Dodecanethiol (C12−SH) was used as a chain transfer agent to prevent gel formation and control the molecular weight. The number average molecular weights of all PBMA samples are ca. 45 000 g/mol. The degrees of branching were determined by 1H NMR. Latex films were cast from a 1:1 mixture of donor- and acceptor-labeled latices. The polymer diffusion in the latex films was studied by measuring the energy transfer (ET) from the donor to the acceptor using the time-correlated single photon counting technique. Polymer diffusion rates increased with decreasing values of Tg when the latex films were annealed at 23 °C. After co...