兩性共聚物：合成以及對水泥砂漿中氧化石墨烯分散性之影響

Abstract

本篇論文的研究主要為合成出一種羧酸系兩性離子型共聚物PD (單(5-氨基-2-(1-(2-((羧甲基)二甲基氨基)乙氧基)-1-氧代丙烷-2-基)-4-甲基-5-氧代戊酸酯)二鈉)，用來改善氧化石墨烯在水泥砂漿中的分散，提升試體的抗壓強度。實驗過程中使用馬來酸酐和DMEA(N,N-二甲基乙醇胺)合成DME(二甲基胺乙基氧羰基丙烯酸)，然後再與氯丁酸鈉鹽反應得到單體DCA(N,N-二甲基((羧酸)丙烯醯氧基乙基)乙酸鈉)，最後使用過硫酸銨為起始劑，與不同比例的丙烯醯胺(AM)經由自由基聚合反應合成得到共聚物PD，經由FTIR和1H-NMR光譜鑑定共聚物的分子結構，並以GPC/SEC測得其分子量。另外，使用modified Hummers法將石墨烯氧化成氧化石墨烯(GO)。將PD加入含GOA的人工孔隙溶液中，透過沉降體積試驗、黏度實驗、粒徑分布與界達電位的測試，探討PD對於GO在人工孔隙溶液中的分散效果。測試結果顯示， GO在人工孔隙溶液中的沉降時間隨著PD之AM/DCA比例的增加，呈現先增後減的趨勢。其中PD在AM/DCA=5時有最長的沉降時間；此外，GO在溶液中的沉降時間隨著PD分子量的上升或添加量的增加，呈現先增後減之趨勢。其中以添加10wt% PD15b時，GO在溶液中的沉降時間為最長，達到45小時，此時溶液的黏度為最低(3.08 mPa‧s)，溶液中GO的D50粒徑為最小、界達電位之負值為最大，分別為127 nm和-25.5 mV，亦即在所合成的共聚物中以PD15b(AM/DCA=5, M̅n=1.8×104)對於氧化石墨烯在孔隙溶液中有最好的分散效果。將PD15b加入含GOA的水泥砂漿中，進行抗壓強度測試，發現添加10wt% PD15b與0.05wt% GOA的砂漿試體，在28天的抗壓強度為34.6 MPa，與未添加GOA、共聚物的控制組相比提升了52.4%。

This thesis is to synthesize a zwitterionic carboxylate copolymer PD(mono(5-amino-2-(1-(2-((carboxylatomethyl)dimethylammonio)ethoxy)-1-oxopropan-2-yl)-4-methyl-5-oxopentanoate)) as a dispersant to improve the dispersion of graphene oxide(GO)in cement mortars and to promote the compressive strength of the cement-based materials.Experimentally, maleic anhydride and DMEA(N,N-dimethylethanolamine) was used to synthesize DME(3-((2-(dimethylamino)ethoxy)carbonyl)acrylic acid).Then, DME was reacted with 4-chlorobutyrate to obtain the monomer DCA (N,N-dimethyl(3-β-(carboxylate) acryloyl oxyethyl) ethanoate). Thereafter, PD copolymer was prepared from DCA and acrylamide(AM) through free radical polymerization by using ammonium persulphate as an initiator. FT-IR and 1H-NMR were used to identify the structure of PD, and GPC/SEC was used to determine the molecule weight of the prepared polymer. Besides, GOA was prepared from graphene using the modified Hummers method.The dispersion property of GOA in the artificial pore solution with PD was evaluated through the sedimentation test, viscosity measurements, size distribution and zeta potential test. The results indicated the sedimentation time of GO in the artificial pore solution increased with AM/DCA ratio of polymer first, reached a maximum value at AM/DCA=5, and then decreased afterwards. The sedimentation time of GO in the pore solution also increased first,reached a maximum value at M̅n=1.8×104, and then decreased afterwards. Namely, PD15b which has AM/DCA=5 and M̅n=1.8×104 showed the best performance.GO in the pore solution with 10 wt% PD15b was found to exhibit the longest sedimentation time, the lowest viscosity, the smallest particle size and highest absolute value of zeta potential of GO, which is 45 hours, 3.08 mPa·s, 127 nm, and -25.5 mV, respectively. Finally, the measured compressive strength of mortar with 0.05wt% GOA and 10wt% PD15b at 28days were 34.6MPa, which were 52.4% increased relative to the mortar without any dispersant or GOA present.