Tailor-made compositional gradient copolymer by a many-shot RAFT emulsion polymerization method
Tailor-made compositional gradient copolymer by a many-shot RAFT emulsion polymerization method
复制标题
通过多次RAFT乳液聚合方法定制组成梯度共聚物
DOI：
10.1039/c4py00003j
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发表时间：
2014
影响因子：
4.6
通讯作者：
Luo Yingwu
中科院分区：
文献类型：
--
作者：
Guo Yunlong;Zhang Jianhua;Xie Peile;Gao Xiang;Luo Yingwu
提出了一种多点RAFT乳液聚合方法来合成具有高相对分子质量和量身定制的组成梯度的梯度共聚聚合物。在该方法中，在反应过程中，以10 ，000 g−-1为靶点，以预先设定的不同组成的共聚单体组成的每一针都是以逐步方式加入的。每次注射后35min，转化率可达95%以上。然后，聚合物链上的组成变化由每一次加入的共聚单体分数直接确定。用该方法合成了相对分子质量高达90 000g−1的苯乙烯/丙烯酸丁酯梯度共聚物(包括线型和V型梯度)。聚合物链上的组成分布与理论预测吻合较好，且聚合物链之间的组成分布较窄。正如预期的那样，梯度共聚物表现出与嵌段共聚物不同的热和相分离性能。这些结果证明了梯度共聚物的定制是成功的。目前的策略将作为一种简便的方法，在短时间内制备定制的高相对分子质量的梯度共聚物。
A many-shot RAFT emulsion polymerization method is proposed to synthesize gradient copolymers with high molecular weight and a tailor-made compositional gradient. In this method each shot consisting of comonomers with pre-set different fractions and targeting the molecular weight of 10 000 g mol−1 was added in a stepwise manner during the reaction. High conversions over 95% were achieved in 35 min after each shot. The compositional variation along the polymer chain was then directly determined by the comonomer fractions added at each shot. Styrene/n-butyl acrylate gradient copolymers (including linear and V-shaped gradient) with molecular weights as high as 90 000 g mol−1 were prepared by this method. The composition profiles along the polymer chains agreed well with the theoretical predictions, and the composition distribution among the polymer chains was narrow. The gradient copolymers showed different thermal and phase separation properties from their block counterparts, as expected. These results demonstrated the successful tailor-making of the gradient copolymers. The current strategy will act as a facile method to prepare tailor-made gradient copolymers with high molecular weights and within a short time.