Thiol-Ene Radical Addition of L-Cysteine Derivatives to Low Molecular Weight Polybutadiene
Thiol-Ene Radical Addition of L-Cysteine Derivatives to Low Molecular Weight Polybutadiene
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DOI：
10.1002/macp.200900164
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发表时间：
2009-09-22
影响因子：
2.5
通讯作者：
Passaglia, Elisa
中科院分区：
文献类型：
--
作者：
Lotti, Luca;Coiai, Serena;Passaglia, Elisa
低分子量液体1，2-聚丁二烯（PBL）的官能化通过经由硫醇-烯自由基反应添加N-乙酰基-L-半胱氨酸或其甲酯来进行。在1，4-二氧六环溶液中并在自由基引发剂（2，2 '-偶氮二异丁腈，AIBN）的存在下进行官能化运行。改变聚合物/半胱氨酸衍生物/引发剂的初始进料比，以突出副反应的发生并理解它们对该方法的可能影响。的H-1 NMR测定的官能化程度带来了高加成度的硫醇，无论初始硫醇/双键的比例。这引起PBL的宏观性质的急剧变化，在亲水性溶剂中（例如在碱性水溶液中）的溶解度提高，玻璃化转变温度显著增加。通过旋光法和圆二色谱法在溶液中评价了从官能化试剂到改性聚合物的手性性质的传播。
The functionalisation of a low molecular weight, liquid 1,2-polybutadiene (PBL) was performed by the addition of either N-acetyl-L-Cysteine or its methyl ester through the thiol-ene radical reaction. The functionalisation runs were carried out in 1,4-dioxane solution and in the presence of a free radical initiator (2,2'-azobisisobutyrronitrile, AIBN). The initial feed ratio polymer/cysteine derivative/initiator was varied, in order to highlight the occurrence of side reactions and to understand their possible influence on the process. The H-1 NMR determination of the functionalisation degree brought out high addition degrees of thiols, regardless of the initial thiol/double bonds ratio. This caused a drastic change in the macroscopic properties of the PBL with improved solubility in hydrophilic solvents (for instance in alkaline aqueous solutions) and impressive increase of the glass transition temperature. The propagation of chiral properties from the functionalising agents to the modified polymers was evaluated by polarimetry and circular dichroism in solution.