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首页> 外文期刊>Journal of Applied Polymer Science >Graft polymerization of vinyl acetate onto granular starch: Comparison on the potassium persulfate and ceric ammonium nitrate initiated system
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Graft polymerization of vinyl acetate onto granular starch: Comparison on the potassium persulfate and ceric ammonium nitrate initiated system

机译：醋酸乙烯酯在粒状淀粉上的接枝聚合：过硫酸钾和硝酸铈铵引发体系的比较

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This work was undertaken to discuss in depth the vital differences in the morphological development during synthesis, and properties of starch-g-poly(vinyl acetate) copolymers using two different initiators, potassium persulfate (KPS) and ceric ammonium nitrate (CAN). KPS-initiated system gave relatively low values of grafting ratio and grafting efficiency, indicating a great tendency for the formation of poly(vinyl acetate) homopolymer (PVAc). Yet, higher values were seen for the CAN-initiated system. Transmission electron microscope observations indicated a relatively broad distribution of latex particles for the KPS-initiated system. The surface potential of latex particles was about -3.5 mV, which turned out to be insufficient to maintain stability of latex particles. On the other hand, a uniform particle size distribution was found for the CAN-initiated system, as the surface potential of latex particles was 21.5 mV. Moreover, radicals on starch molecules were generated directly through a redox reaction with positively charged ceric ion. The hydrophobic PVAc chains were thus grafted on starch, resulting in an amphiphilic graft copolymer, which provides a sufficient stabilization degree as a role of surfactant to render a relatively uniform distribution of latex particles. The synthesized starch-g-poly(vinyl acetate) copolymers were further converted to starch-g-poly(vinyl alcohol) through saponification, which were subjected to evaluations regarding the biodegradation and cell culture capability. (c) 2006 Wiley Periodicals, Inc.
机译：进行这项工作以深入讨论合成过程中形态发展的重要差异，以及使用两种不同的引发剂过硫酸钾（KPS）和硝酸铈铵（CAN）的淀粉-g-聚乙酸乙烯酯共聚物的性能。 KPS引发的体系给出相对较低的接枝率和接枝效率值，表明形成聚乙酸乙烯酯均聚物（PVAc）的趋势很大。但是，CAN启动系统的价值更高。透射电子显微镜的观察结果表明，KPS引发体系的胶乳颗粒分布相对较广。胶乳颗粒的表面电势约为-3.5mV，结果不足以维持胶乳颗粒的稳定性。另一方面，由于胶乳颗粒的表面电势为21.5 mV，因此对于CAN引发的系统发现了均匀的粒径分布。此外，淀粉分子上的自由基是通过与带正电的铈离子的氧化还原反应直接产生的。疏水的PVAc链因此接枝到淀粉上，形成两亲性接枝共聚物，该两亲性接枝共聚物作为表面活性剂的作用提供了足够的稳定度，以使胶乳颗粒分布相对均匀。通过皂化将合成的淀粉-g-聚（乙酸乙烯酯）共聚物进一步转化为淀粉-g-聚（乙烯醇），对其进行生物降解和细胞培养能力的评价。 （c）2006年Wiley Periodicals，Inc.

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