羧酸系分散劑的合成以及對水泥漿體性質的影響

黃甄玲

指導教授 ： 許貫中

國立臺灣師範大學/理學院/化學系/碩士(2003年)

摘要

本論文合成二種羧酸系共聚合物PCA(1)、PCA(2)，作為水泥漿體的分散劑。PCA(1)、PCA(2)分別以單體PF1或PT1(具一邊側鏈)、PF2-Na(具二邊側鏈)與MAA經自由基聚合反應而得，並再由1H-NMR，IR、與UV光譜分析確認其結構；利用GPC測定共聚物的分子量。實驗過程中改變單體比例、起始劑或是鏈轉移劑濃度、反應溫度、以及側鏈長度而合成出不同的共聚物，探討共聚物的單體比例、分子量、與側鏈等因素對於水泥漿體(W / C = 0.3)之迷你坍度、迷你坍度維持的影響，並以分散劑對水泥顆粒之吸附行為解釋之。
研究結果顯示添加PCA(1)的水泥漿體之迷你坍度與迷你坍度維持都比添加PCA(2)者佳。添加的PCA(1)以短側鏈，PF1 : MAA = 4 : 1，且Mw = 1.3 × 104的效果為最佳。PCA(1)結構中含側鏈較長者，因側鏈過長發生架橋現象，造成水泥漿體粒子的凝聚，反而與水泥漿體的相容性較差。添加的PCA(2)以PF2-Na : MAA = 2 : 3且Mw = 2.6 × 104的效果最佳，但水泥漿體的迷你坍度維持仍不佳。PCA結構中含MAA比例愈高(＞80%)，在60 ~ 90分鐘時在水泥表面的吸附變化量愈大，則所形成水泥漿體流動性的維持愈佳。反之，如果PCA在初期就快速且大量吸附於水泥粒子者，水泥漿體的維持性便較差。

關鍵字

羧酸系分散劑 ； 單體比例 ； 分子量 ； 側鏈

並列摘要

This thesis has synthesized two carboxylate-based copolymer ( PCA(1) and PCA(2) ) as a dispersant of cement pastes. PCA(1) was prepared from PF1 or PT1 which has one side chain, and MAA through a free radical polymerization. PCA(2) was prepared from PF2-Na which has two side chains, and MAA through a free radical polymerization. The structures of PCA(1) and PCA(2) were determined and confirmed by the 1H-NMR, IR, and UV spectra. The molecular weight of copolymers was determined through GPC measurements. Experimentally, PCAs with different monomer ratio, molecular weight, and side chain length, were prepared, and their effects on the mini-slump and mini-slump retention of cement pastes (water / cement = 0.3) were investigated. The results were explained by the adsorption behavior of PCA(1) and PCA(2) on cement particles.
It is indicated that PCA(1) has better the mini-slump and mini-slump retention of cement pastes than PCA(2). Cement pastes containing PCA(1) with short side chains, PF1 / MAA = 4 / 1, weight-average molecular weight (Mw) equal to 1.3 × 104, show the highest mini-slump and the best mini-slump retention. PCA(1) containing long side chains is less compatible with cement, because the polymer would bridge different cement particles, and cause cement pastes to become coagulated. Cement pastes containing PCA(2) with PF2-Na / MAA = 2 / 3, Mw = 2.6 × 104 show the highest mini-slump, but the mini-slump retention of cement pastes is not good. For PCA with more MAA content (＞80%), a large portion of the polymer was adsorbed onto cement particles in 60~90 min. This enhances the mini-slump retention of the resulting cement pastes. When PCA was quickly adsorbed onto cement particles in large amount initially, mini-slump loss of cement pastes would occur.

並列關鍵字

carboxylate-based dispersant ； monomer ratio ； molecular weight ； side chain

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