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首页> 外文期刊>Macromolecules >One-pot synthesis of natural rubber-based telechelic cis -1,4-polyisoprenes and their use to prepare block copolymers by RAFT polymerization
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One-pot synthesis of natural rubber-based telechelic cis -1,4-polyisoprenes and their use to prepare block copolymers by RAFT polymerization

机译：一锅合成天然橡胶基远螯顺式-1,4-聚异戊二烯及其在RAFT聚合反应中制备嵌段共聚物的应用

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摘要

We investigate the one-pot synthesis of a new α,ω- bistrithiocarbonyl-end functionalized telechelic cis-1,4-polyisoprene (Pip) via metathesis degradation from natural rubber (NR) in the presence of the Grubbs second generation catalyst (GII) and a bistrithiocarbonyl-end functionalized olefin as a chain transfer agent (CTA). When the metathesis degradation of the NR of 2 × 10~6 g mol~(-1) molecular weight is performed in toluene at 25 ° using the ratio of [Ip]_0/[GII] _0/[CTA]_0 = 100/1/1 (Ip = isoprene units), a cis-1,4-polyisoprene of 14000 g mol~(-1) after 4 h is obtained. The functionality estimated by ~1H NMR spectroscopy is equal to 1.5 ± 0.1. The structure of telechelic cis-1,4-polyisoprene was confirmed by combination of 1H NMR, ~(13)C NMR spectroscopy and FTIR. The influence of the CTA concentration was investigated. It was found that using higher concentrations of CTA ([Ip]_0/[GII]_0/[CTA] _0 of 100/1/2 and 100/1/5) lead to form a perfectly telechelic cis-1,4-polyisoprene with a functionality of 2 with no significant difference in M_n values (approximately 6400 g mol~(-1)) and in polydispersity indices (～1.70). The new well-defined α,ω- bistrithiocarbonyl-end functionalized telechelic cis-1,4-polyisoprenes were used successfully as macromolecular chain transfer agents (macroCTAs) to mediate the RAFT polymerization of t-BA using AIBN as the initiator ([t-BA] _0/[macroCTA]_0/[AIBN]_0 = 500/1/0.4) in toluene at 60 ° leading to well-defined P(t-BA)-b-PIp-b-P(t-BA) triblock copolymers.
机译：我们研究了新的α，ω-双三硫代羰基末端官能化螯合顺式1,4-聚异戊二烯（Pip）的合成，该反应是通过在天然橡胶（NR）的复分解作用下在格鲁布斯第二代催化剂（GII）存在下进行的以及作为链转移剂（CTA）的双三硫代羰基末端官能化的烯烃。当[25]在甲苯中，[Ip] _0 / [GII] _0 / [CTA] _0 = 100 /时，分子量为2×10〜6 g mol〜（-1）的NR的复分解反应在甲苯中进行。 1/1（Ip =异戊二烯单元），在4 h后获得14000 g mol〜（-1）的顺式1,4-聚异戊二烯。通过〜1H NMR光谱估计的官能度等于1.5±0.1。通过1H NMR，〜（13）C NMR光谱和FTIR的结合，确定了远螯顺式1，4-聚异戊二烯的结构。研究了CTA浓度的影响。发现使用较高浓度的CTA（[Ip] _0 / [GII] _0 / [CTA] _0为100/1/2和100/1/5）可形成完美的远螯顺式1，4-聚异戊二烯官能度为2，M_n值（约6400 g mol〜（-1））和多分散指数（〜1.70）无显着差异。新型定义明确的α，ω-双三硫代羰基末端官能远螯顺式1,4-聚异戊二烯已成功用作大分子链转移剂（macroCTA），以AIBN为引发剂介导了t-BA的RAFT聚合（[t-在60°的甲苯中的BA] _0 / [macroCTA] _0 / [AIBN] _0 = 500/1 / 0.4）产生定义明确的P（t-BA）-b-PIp-bP（t-BA）三嵌段共聚物。

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