新型聚羧酸系強塑劑的合成與應用

葉一賢(Ye Yi-Shian)

指導教授 ： 許貫中

國立臺灣師範大學/理學院/化學系/碩士(2001年)

摘要

傳統混凝土為了提高工作度，必需添加多量的水，如此一來，雖然提高了工作度，卻因此降低了混凝土的強度。添加強塑劑能夠大幅降低需水量，得以拌製低水膠比、高流動性、高強度的混凝土。
本研究合成一種新型的聚羧酸系聚合物(PMAMP)，作為混凝土強塑劑。PMAMP係以甲基丙烯酸(MAA)與2-丙烯醯胺-2甲基丙烷磺酸(AMPSA)為反應物，經自由基聚合反應而得。在實驗過程中，合成各種PMAMP，其MAA/AMPSA比例分別為1/4、2/3、1/1、3/2、4/1，重量平均分子量為2.5×104~4.1×105。拌製水泥漿(水灰比0.3)，砂漿(水灰比0.42)和混凝土(水膠比0.42)。探討PMAMP的反應物比例和分子量對於各水泥質材料性質的影響。
從水泥漿的測試結果得知，隨著PMAMP的分子量增加，漿體的迷你坍度呈現先增後減的趨勢，在PMAMP分子量約為4~6×104時，漿體有最高的迷你坍度值；隨著MAA/AMPSA比例的增加，水泥漿體的迷你坍度趨勢亦是先增後減，在MAA/AMPSA=3/2~1/1時，漿體有最高的迷你坍度值。另外，在砂漿與混凝土也得到相似結果。比起商用的磺酸系強塑劑HPC1000，在同一配比下PMAMP需要較少的劑量即可達到相同的工作性，且具有較佳的坍度維持效果。

關鍵字

羧酸系強塑劑 ； 迷你坍度 ； 坍度損失 ； 分子量 ； 反應物比例

並列摘要

More water is usually added into concrete to achieve good workability, and this causes a decrease of the concrete strength. The addition of superplasticizers can reduce the water demand enormously and therefore make the resulting concrete with low water/binder ratio with improved workability and higher strength.
This thesis has synthesized a new carboxylate-based copolymer (PMAMP) as a concrete superplasticizer. PMAMP was prepared from methacrylic acid (MAA) and 2-acrylamido-2-methylpropane sulfonic acid (AMPSA) through a free radical copolymerization. Experimentally, PMAMPS with different MAA/AMPSA ratios (i.e.,1/4,2/3,1/1,3/2,4/1) and different molecular weights (Mws) ranging from 2.5×104 to 4.1×105 were prepared. Cement pastes (W/C=0.3), mortars (W/C=0.42) and concrete (W/B=0.42), were made. The effects of the MAA/AMPSA ratio and Mw of PMAMP on the properties on cementitious materials were investigated.
The results of cement pastes indicate that as Mw is increased, the mini-slump of pastes increases first, reaches a highest value at Mw about 4~6×104, and then decreases afterwards. As MAA/AMPSA is increased, the mini-slump of pastes also increases first, reaches a maximum , and then decreases subsequently. Cement pastes with MAA/AMPSA= 3/2~1/1, show the highest slump values. The results of mortars and concretes are similar to those of cement pastes. Compared to the commercial sulfonate-based superplasticizer (HPC1000), PMAMP requires less amount to make concrete with same workability and shows better slump-retention effect.

並列關鍵字

carboxylate-based superplasticizer ； mini-slump ； slump loss ； molecular weight ； reactant ratio