Mechanochemically triggered bond formation in solid-state polymers
Mechanochemically triggered bond formation in solid-state polymers
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DOI：
10.1039/c0jm03875j
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发表时间：
2011-01-01
影响因子：
--
通讯作者：
Craig, Stephen L.
中科院分区：
文献类型：
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作者：
Black, Ashley L.;Orlicki, Joshua A.;Craig, Stephen L.
聚丁二烯用二溴-、二氯-和溴氯-卡宾官能化以得到偕-二卤代环丙烷化（gDHC）聚合物，其中gDHC充当机械活化的官能团或机械载体。将聚合物挤出以确定固态下的机械活性团活性。gDHC开环的程度取决于聚合物组成和宏观剪切应力，在挤出1小时后为6.0%至超过30%。此外，发现由偕-二溴环丙烷的机械活化形成的2，3-二溴烯烃在固态下经历随后的氯化物亲核取代。固态取代反应的数量远远超过主链键断裂的数量，这一发现对未来在自增强或自修复聚合物中使用机械载体具有影响。
Polybutadiene was functionalized with dibromo-, dichloro-, and bromochloro-carbene to give gem-dihalocyclopropanated (gDHC) polymers, in which the gDHCs act as mechanically activated functional groups or mechanophores. The polymers were extruded to determine the mechanophore activity in the solid state. The extent of gDHC ring opening depends on both the polymer composition and the macroscopic shear stress, ranging from 6.0% to over 30% after an hour of extrusion. In addition, the 2,3-dibromoalkene formed from mechanical activation of the gem-dibromocyclopropane was found to undergo subsequent nucleophilic substitution by chloride in the solid state. The number of solid-state substitution reactions far exceeds the number of main-chain bonds broken, a finding with implications for the future use of mechanophores in self-strengthening or self-healing polymers.