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研究生:陳正國
研究生(外文):Cheng, Jeng-Kwo
論文名稱:常溫胺解室溫熟化矽橡膠之研究
論文名稱(外文):A Study on the Aminolysis Room Temperature Vulcanized Silicone Rubber
指導教授:張正良張正良引用關係
指導教授(外文):Chang Cheng-Liang
學位類別:碩士
校院名稱:淡江大學
系所名稱:化學工程學系
學門:工程學門
學類:化學工程學類
論文種類:學術論文
論文出版年:1996
畢業學年度:84
語文別:中文
論文頁數:91
中文關鍵詞:胺解聚二甲基矽氧高分子咬尾效應矽橡膠溶劑效應
外文關鍵詞:aminolysispolydimethylsiloxanebackbitingsilicone rubbersolvent effect
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本研究是應用胺解反應於裂解二甲基聚矽氧橡膠交聯結構;經由系統化
的裂解實驗,找出最適化反應條件,可以選擇性地獲得直鏈聚矽氧高分子
產物或環狀產物。 由於立體阻礙, 在測試各級胺類時,發現胺類完全裂
解交聯結構快慢順序如下:一級胺>二級胺>三級,在測試各級胺類時,
發現胺類完全裂解交聯結構快慢順序如下:一級胺>二級胺>三級胺。在
一定的裂解時間下,產物中環狀物含量多寡排列順序為:一級胺>二級胺
。裂解時間愈長產物之分子量愈小;昇高裂解溫度會增快反應的進行。
二乙基胺為裂解劑時,佐以KOH催化,裂解時間為七至十小時,直鏈產物
平均分子量為七千至四千。產物由GPC、FTIR及NMR分析其構造,確定產物
的主鏈是由矽氧重覆單元構成,末端基為二乙胺基及羥基。 在胺解反應
中,藉乙醇的加入可增加KOH溶解度使原本兩固一液的反應系統變成一液
一固反應系統,大幅增加KOH的溶解度,裂解速率因此而加速,對於完全
破壞矽橡膠 交聯結構的時間,可由八小時減為二十五分鐘。這一裂解系
統在THF極性溶劑環境下 ,咬尾效應大幅增快,主產物為D4、D5、D6等環
狀物,其中以D4含量最高。此裂解系統若使用非極性甲苯溶劑,由於裂解
後之聚矽氧高分子鏈,其末端極性官能基,在非極性環境下活性衰退,造
成高分子主鏈較不易發生咬尾,最後獲得高分子產物分子量為一萬七千,
其末端基為羥基與乙氧基。
Strong base enhanced aminolysis reaction of room temperature
vulcanized polydimethylsiloxane network was studied under
ambient temperature. It wasfound that time for complete
dissolution of PDMS network was affectedby steric effect, the
activity of the amine decreased in the order primary >secondary
>tertiary. The external diffusion limitation was also found tobe
significant, The average molecular weight of the linear polymer
productsdecreased while the yield of the cyclic products
increasedcontinuously after the initial dissolution stage which
indicatedthat cyclization was the main reaction in the final
stage. The reaction rate was enhanced by increasing the
temperature. The average molecular weight of the
linear products were found tobe 7000 and 4000 when the reaction
time were 7 and 10 hours respectively. Theyield was around 85%.
The end groups of the polymer products were amino-diethyl group
and hydroxyl group. D4 was the main cyclic product. By adding
ethanol to diethylamine,potassium hydroxide was soluble in
thecosolvent, which greatly enhanced the nucleophilic cleavage
reaction of theSi-O bond by amine. Complete dissolution time was
reduced from 8 hours to25 minites. However, backbiting effect
was found to be important using polar solvents ,as was evidenced
by the fact that the main products were cycliccompounds, mostly
D4. If less polar solvents were employed,the main products
became linear siloxane polymers with measured weight average
molecular weightof 17000. In this case, the end group were
hydroxyl group and ethoxyl group.
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