兩性水膠作為水泥砂漿自養護劑可行性的探討

Abstract

本篇主要研究是利用一兩性水膠PDA作為自養護劑，首先將馬來酸酐和N,N-二甲基胺乙醇反應得到出二甲基胺乙基氧羰基丙烯(DME)，DME再與氯醋酸鈉反應合成出單體N,N-二甲基胺-3-β-羧基丙烯酸乙酯乙酸鈉鹽(DCA)，最後將單體和丙烯醯胺以自由基聚合的方式反應得到PDA水膠，探討在不同單體比例、交聯劑劑量與起始劑劑量下水膠對於純水吸水率的影響，以及在不同pH值、溫度與鹽水下吸水率之影響，合成之DME和DCA以FT-IR鑑定結構，將合成之PDA水膠添加於水泥砂漿試體中，探討加入水膠對試體重量損失、內部相對濕度、抗壓強度、塑性乾縮與乾燥乾縮的影響。 實驗結果顯示在DCA：AM＝4：6、MBA＝0.5 mol%、APS＝0.2 mol%條件下反應合成的PDA在純水和鹽水有最高的吸水率，分別在純水的吸水率為312.5 g/g；在0.1M NaCl溶液下吸水率為31.7 g/g；在0.1M CaCl2溶液下吸水率為22.3 g/g，另外添加適量的PDA可減少水泥砂漿試體的重量損失、維持內部相對濕度、增加抗壓強度，在塑性乾縮和乾燥乾縮方面，與控制組相比之下亦有實際的改善效果，最後使用XRD和DSC分別對水化反應所產生的氫氧化鈣進行定性與定量的分析。In this paper is using an amphoteric hydrogel poly(DCA-co- acrylamide) (PDA) as a self-curing agent of mortar. At first, DME (3-((2-(dimethylamino)ethoxy)carbonyl) acrylic acid) was reacted by maleic anhydride and N,N-dimethylethanol -amine.Then DCA was obtained from DME and sodium chloroacetate. At last, DCA was reacted with acrylamide to obtain PDA hydrogel. The effect of the monomer ratio, initiators, and crosslinkers of PDA on the swelling ratio in water was investigated. We also measure swelling ratio of hydrogel in different pH, temperatures and saline solution. The structure of PDA was confirmed by the FT-IR spectra. The effect of containing PDA on weight loss, water retention, relative humidity, compressive strength, plastic shrinkage and drying shrinkage. of mortars were investigated. The results indicate that the maximum swelling ratio of PDA (DCA：AM = 4：6；APS = 0.2 mol%；MBA = 0.5 mol%) is 312.5 g/g in water and 31.7 g/g, 22.3 g/g in 0.1M NaCl, 0.1M CaCl2 solution. Added PDA as a a self-curing agent of mortar which can improve weight loss, water retention, relative humidity, compressive strength, plastic shrinkage and drying shrinkage, rather than control group. Fanilly, the hydration degree of cement pastes was measuring by XRD (qualitative analysis) and DSC (quantitative analysis).