Effect of linker structure on salicylic acid-derived poly(anhydride-esters)
Effect of linker structure on salicylic acid-derived poly(anhydride-esters)
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DOI：
10.1021/ma048051u
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发表时间：
2005-08-09
期刊：
影响因子：
5.5
通讯作者：
Uhrich, KE
中科院分区：
文献类型：
--
作者：
Prudencio, A;Schmeltzer, RC;Uhrich, KE
通过熔融聚合方法合成了一系列水杨酸衍生的聚（酸酐-酯），其中将两种水杨酸连接在一起的分子（“连接体”）的结构是不同的。为了确定连接体与相应聚(酸酐-酯)的物理性质之间的关系，评估了几种连接体，包括直链脂肪族、芳香族和脂肪族支化结构。对于直链脂肪族连接体，通过更长的直链烷基链可以获得更高的分子量。空间位阻最大的连接体产生较低分子量的聚合物。热分解温度随着烷基链长度的增加而增加，但由于聚合物柔韧性的增强，玻璃化转变温度降低。由于 pi-pi 相互作用增强，使用芳香族连接基可获得最高的玻璃化转变温度。水接触角决定了聚合物的相对疏水性，这与水解降解率相关；即，最高的接触角值产生最慢的降解聚合物。
A series of salicylic acid-derived poly(anhydride -esters) were synthesized by melt polymerization methods, in which the structures of the molecule ("linker") linking together the two salicylic acids were varied. To determine the relationship between the linker and the physical properties of the corresponding poly(anhydride-ester), several linkers were evaluated including linear aliphatic, aromatic, and aliphatic branched structures. For the linear aliphatic linkers, higher molecular weights were obtained with longer linear alkyl chains. The most sterically hindered linkers yielded lower molecular weight polymers. The thermal decomposition temperature increased with the alkyl chain length, but the glass transition temperature decreased, due to the enhanced flexibility of the polymer. The highest glass transition temperatures were obtained by using aromatic linkers as a result of inereased pi-pi interactions. Water contact angles determined the relative hydrophobicity of the polymers, which correlated to hydrolytic degradation rates; i.e., the highest contact angle values yielded the slowest degrading polymers.