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Valencene as a naturally occurring sesquiterpene monomer for radical copolymerization with maleimide to induce concurrent 1:1 and 1:2 propagation
Polymer Degradation and Stability ( IF 5.9 ) Pub Date : 2019-01-25 , DOI: 10.1016/j.polymdegradstab.2019.01.025
Hiroaki Hashimoto , Hisaaki Takeshima , Tomonari Nagai , Mineto Uchiyama , Kotaro Satoh , Masami Kamigaito

Valencene, a naturally occurring sesquiterpene that can be obtained from various citrus fruits, was copolymerized as an unconjugated 1,1-disubstituted bulky vinyl monomer by radical copolymerization with conjugated monomers possessing electron-withdrawing substituents, such as maleimides, acrylates, methacrylates, acrylonitrile, and methacrylonitrile, in toluene and PhC(CF3)2OH. The fluorinated alcohol increased the copolymerizability, as in the radical copolymerization of other unconjugated non-polar olefins with those electron-acceptor comonomers. In particular, the copolymerization of valencene and N-phenylmaleimide in PhC(CF3)2OH proceeded via concurrently occurring 1:1 and 1:2 propagation, in which the monomer reactivity ratio of maleimide and valencene to the maleimide radical with the penultimate valencene unit was close to 1 according to a kinetic analysis of the copolymerization based on the penultimate model. Therefore, the copolymerizability of valencene was higher than that of limonene, which is a similar unconjugated 1,1-disubstituted vinyl monomer with a smaller cyclohexenyl substituent that undergoes selective 1:2 radical copolymerization with maleimide derivatives under the same conditions. Reversible addition-fragmentation chain transfer RAFT copolymerization using a trithiocarbonate resulted in copolymers with controlled molecular weights and chain-end groups. The biobased copolymers of valencene and N-phenylmaleimide showed relatively high glass transition temperatures (Tg) of approximately 220–240 °C and relatively high thermal stability with 5% decomposition temperatures (Td5) of approximately 330–340 °C due to their rigid main-chain structures.



中文翻译:

瓦伦烯是天然的倍半萜烯单体,可与马来酰亚胺进行自由基共聚,诱导同时1:1和1:2传播

瓦伦烯是一种天然的倍半萜烯,可以从各种柑橘类水果中获得,通过与具有吸电子取代基的共轭单体,例如马来酰亚胺,丙烯酸酯,甲基丙烯酸酯,丙烯腈,和甲基丙烯腈,分别在甲苯和PhC(CF 32 OH中。氟化醇提高了共聚能力,就像其他未共轭的非极性烯烃与那些电子受体共聚单体的自由基共聚一样。尤其是,瓦伦烯和N-苯基马来酰亚胺在PhC(CF 32中的共聚OH通过同时发生的1:1和1:2传播进行,根据倒数第二个模型,根据共聚反应的动力学分析,马来酰亚胺和valencene与倒数第二个valencene单元的顺丁烯二酰亚胺自由基的单体反应率接近1。 。因此,瓦伦烯的共聚性高于柠檬烯,后者是具有较小环己烯基取代基的相似的未共轭的1,1-二取代乙烯基单体,在相同条件下与马来酰亚胺衍生物进行选择性1:2自由基共聚。使用三硫代碳酸酯的可逆加成-断裂链转移RAFT共聚反应可制得分子量和链端基均受控的共聚物。瓦伦烯和的生物基共聚物-苯基马来酰亚胺显示出较高的玻璃化转变温度(T g),约为220–240°C,并且由于其刚性的主链结构,具有5%的分解温度(T d5),约为330–340°C,具有较高的热稳定性。

更新日期:2019-01-25
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