Pulses of fast electrons as a tool to synthesize poly(acrylic acid) nanogels. Intramolecular cross-linking of linear polymer chains in additive-free aqueous solution
Pulses of fast electrons as a tool to synthesize poly(acrylic acid) nanogels. Intramolecular cross-linking of linear polymer chains in additive-free aqueous solution
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DOI：
10.1021/ma021628s
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发表时间：
2003-04-08
期刊：
影响因子：
5.5
通讯作者：
Ulanski, P
中科院分区：
文献类型：
--
作者：
Kadlubowski, S;Grobelny, J;Ulanski, P
聚（丙烯酸）纳米凝胶已经合成使用一种新的方法，基于在水溶液中的线性大分子的分子内交联，诱导短（几微秒）脉冲的快电子。同时产生的一些碳为中心的自由基沿着聚合物链的结果主要是分子内重组，只有一个较小的贡献分子间交联形成和断链。这种新方法允许在纯体系中合成纳米凝胶，该纯体系仅由聚合物和水组成，在不存在单体、交联剂等的情况下。通过调节聚合物浓度和辐射剂量，可以控制纳米凝胶的分子量和尺寸。的产品已被其特征在于静态光散射，粘度计，和原子力显微镜，而非经典动力学的分子内重组已遵循时间分辨光谱。聚（丙烯酸）的纳米凝胶比母体线性链更能抵抗自由基诱导的降解。
Nanogels of poly(acrylic acid) have been synthesized using a new method, based on intramolecular cross-linking of linear macromolecules in aqueous solution, induced by short (a few microseconds) pulses of fast electrons. Simultaneous generation of a number of carbon-centered radicals along the polymer chain results in predominantly intramolecular recombination, with only a minor contribution of intermolecular cross-link formation and chain scission. This new method allows the synthesis of nanogels in a pure system consisting only of polymer and water, in the absence of monomers, cross-linking agents, etc. Adjusting the polymer concentration and dose of radiation, one can control the molecular weight and dimensions of nanogels. The products have been characterized by static light scattering, viscometry, and atomic force microscopy, while the nonclassical kinetics of intramolecular recombination has been followed by time-resolved spectroscopy. Nanogels of poly(acrylic acid) are much more resistant to free-radical-induced degradation than the parent linear chains.