Free-radical ring-opening polymerization of cyclic allylic sulfides
Free-radical ring-opening polymerization of cyclic allylic sulfides
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DOI：
10.1021/ma960573p
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发表时间：
1996-10-21
期刊：
影响因子：
5.5
通讯作者：
Rizzardo, E
中科院分区：
文献类型：
--
作者：
Evans, RA;Rizzardo, E
研究了一种新型的开环单体，发现它可以进行简便、高效的自由基聚合。以6-亚甲基-1，4-二硫杂环戊烷(3)和3-亚甲基-1，5-二硫代环辛烷(4)为例合成了环烯丙基硫化物。6-亚甲基-1，4-二硫杂环辛烷(3)是一种透明的油，3-亚甲基-1，5-二硫代环辛烷(4)的熔点很低，接近常温，与许多开环单体不同，它们很容易在潮湿和含水的酸碱中存活。这些化合物在完全开环的情况下进行本体聚合，得到了玻璃化转变温度约为-30~-50℃，熔点约为100~130℃的高不溶高分子量结晶均聚物(M(W)约为500 000~700 000)。用FT-IR、高温H-1和C-13核磁共振光谱、高温GPC和DSC对均聚物及其1：1共聚物进行了表征。尽管最终聚合物中存在结晶度，但它们的体积收缩在预期的开环单体(4.5%-8.5%)的分子量范围内。
A new type of ring-opening monomer has been investigated and found to undergo facile and efficient free-radical polymerization. The monomers are cyclic allylic sulfides with 6-methylene-1,4-dithiepane (3) and 3-methylene-1,5-dithiacyclooctane (4) synthesized and investigated as two examples. 6-Methylene-1,4-dithiepane (3) is a clear oil and 3-methylene-1,5-dithiacyclooctane (4) has a low, near ambient temperature melting point, and in contrast to many ring-opening monomers, they readily survive exposure to moisture and aqueous acids and bases. These compounds were polymerized in bulk with complete ring opening to give highly insoluble crystalline homopolymers of high molecular weight (M(w) ca. 500 000-700 000) with glass transition temperatures of ca. -30 to -50 degrees C and melting points of ca. 100-130 degrees C. The homopolymers and their 1:1 copolymer were characterized by FT-IR and high-temperature H-1 and C-13 NMR spectroscopies, high temperature GPC, and DSC. They displayed volume shrinkages in the range expected of ring-opening monomers (4.5-8.5%) of their molecular weights in spite of the crystallinity present in the final polymers.