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標題: Photo-Synthesis of Aliphatic Bisazetidine-2,4-Diones for Preparation of Semi-crystalline Polymalonamides and Elastomers
作者: 葉忠倫
Yeh, Chung Lun
關鍵字: Azetidine-2;高分子;4-diones;Polymalonamides;Elastomer;彈性體
出版社: 化學工程學系
此脂肪族的Azetidine-2,4-dione的合成可由脂肪族二元胺與甲酸以熱化學方式合成Bis-formamide開始,作為第一步,再與醯氯酸(Methacryloyl chloride)常溫縮合成Bis-formyl-methacrylamide為第二步,最後第三步於丙酮溶液中進行光化學環化反應而形成脂肪族二元之 Azetidine-2,4-dione。
所製得之二元脂肪族Azetidine-2,4-diones發現具有如下優良高分之子中間體特質:(1)它的熱穩定性高,熱裂解溫度在200℃以上。(2)它是一具有高選擇性的活性官能基,可與脂肪族的一級胺在室溫即可進行開環反應,且其加成反應快速、產率極高,而且無副產物之生成。(3)脂肪族的一級胺若與醇(ROH)、苯胺(Ph-NH2)及二級胺( ),若同時同步加入Azetidine-2,4-dione進行開環時,一級胺具有絕對的反應選擇性。
本研究以Bis-azetidine-2,4-diones為高分子原料,和脂肪族一級二元胺利用熔融法進行開環反應,而一步(One-Pot)製備高分子量之Polymalonamides以及其相關彈性體。而控制二元胺之鏈長可改變Polymalonamides之Tg及Tm,並依此控制高分子之物性,使其應用於不同之範圍,並與先前本實驗室所製作的芳香族之Polymalonamide來比較,最不相同之處是此系列的高分子大部分是結晶型高分子,其Td(TGA)皆高達370 ℃左右,顯示其抗熱性較PU及芳香族系列的Polymalonamide為佳,且吸水性低約在0.2~2.1%之間。
本論文進一步利用二元胺與Azetidine-2,4-diones之聚合製備一一系列之醯胺類彈性體。製做時分二步進行,第一步利用Jeffamine D2000(聚醚胺)Bis-Azetidine-2,4 -dione製備含軟鏈段之高分子預聚合物,第二步再將短鏈之二元胺(硬鏈段)加入高分子預聚合物中完成彈性體之製備。所製備出之彈性體利用DSC探討其熱性質,並利用AFM作其表面型態分析,以了解其硬段/軟段(結晶區/非結晶區)之分布情況。初步的結構分析,顯示硬鏈段亦能在彈性體中形成部分之結晶型態,而形成規則之軟硬二相分離之結構。吸水性方面則略高於Polymalonamides系列。
而Polymalonamide Elastomer,其Td明顯高於Polyurethane (PU),藉此改善PU熱穩定性不佳之缺點。

This study concerns the synthesis of novel aliphatic bis-azetidine-2, 4-diones and their applications in syntheses of polymalonamides and polymalonamide elastomers.
In the first step of our three-step scheme toward aliphatic bis-azetidien-2,4-dione preparation, short-chained aliphatic diamines were reacted with formic acid to form bis-formamides. The bis-formamaids were then treated with methacryloyl chloride in formation of bis-formyl-methacrylamide. In the final step, the later was converted into aliphatic bis-azetindine-2,4-dione by a photo-sensitized cyclization. The overall yields of bis-azetidine-2,4-diones has been enhanced to 65~86% ranges.
The aliphatic azetidine-2, 4-diones prepared have been found to have several exceptional properties suited for polymer preparation. Firstly, they are thermally stable up to 200℃ with little decomposition detected when heated. Secondly, they react rapidly and quantitatively with aliphatic primary amines into polymaloniamides at ambient temperatures. In the presence of other compounds with active hydrogen such as alcohols, aniline or secondary amines, bis-azetidine-2,4-diones seem to prefer reacting with more basic primary aliphatic amines selectively.
Series of aliphatic polymalonamides were prepared conveniently by a ring-opening, one-step melt process between diamines and bis-azetidine-2,4-diones. Unlike the properties observed previously for the aryl-polymalonamides which are amorphous, all aliphatic polymalonamide are semi-crystalline polymers with Tm observed between 120 to 297 ℃ depending upon the carbon chain-length between the amide-amide groups. They exhibited better thermal stability than aryl-polymalonamides showing Td of greater than 370 ℃. Their water absorption levels are between 0.2 to 2.1%, which are also substantially lower than the commercial Nylons.
The same melt polymerization process has been extended in the preparation of polymolonamide elastomers. This is done in a two-step process by mixing a high molecular weight polyether diamine ( Jeffamine D2000) and bis-azetidine-2,4-diones to form the soft chain prepolymer first. In the subsequent finishing step, the prepolymers were then added with short-chain aliphatic diamines as chain extenders at 140 ℃. Polymalonamide elastomers exhibited a low Tg of -55~60 ℃. In the meantime, most of the elastomers also showed dinstinct crystalline hard segment domains detected by AFM analysis .
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