메톡시폴리에틸렌글리콜모노메타크릴레이트(MPEGMAA)와 메타크릴산(MAA)의 몰비와 MPEGMAA의 폴리에틸렌옥사이드(PEO)의 길이를 변화시켜 합성한 폴리카복실레이트계 고유동화제(PCA)를 시멘트 모르타르에 첨가한 경우. 그 물성에 미치는 영향에 대하여 조사하였다. PEO의 길이가 긴 경우 ［MPEGMAA］/［MAA］ 몰비가 낮을수록 모르타르의 유동성은 향상되었다. PCA를 첨가했을 때 응결시간은 지연되며, PEO의 길이가 짧고 ［MPEGMAA］/［MAA］ 몰비가 낮을수록 응결은 더 지연되었다. 특히 MPEGMAA의 분자량이 475인 경우(에틸렌옥사이드 반복단위는 10이다) 응결시간의 지연이 가장 컸다. PCA 분자내 존재하는 PEO의 영향으로 표면장력은 크게 낮아지며, 몰탈의 기공크기분포를 크게 변화시쳤다. PCA에 의해 생성되는 기공은 대부분 7∼370$mu extrm{m}$ 범위의 거대 기공이며, 이 기공들에 의해 몰탈의 밀도와 압축강도가 낮아지게 되었다.
This paper presents the experimental results on the properties of the cement mortar with polycarboxylate-type superplasticizers PCA) which were synthesized by different mole ratio of methoxypoly(ethyleneglycol)monomethacrylate (MPEGMAA) and methacrylic acid (MAA) and by different length of polyethyleneoxide (PEO). As the PEO chain was longer and mole ratio of [MPEGMAA]/[MAA] was lower, the fluidity of cement mortar was better. The setting time of mortar with PCA was retarded, and as PEO chain was shorter and [MPEGMAA]/[MAA] was lower, it was more retared. Espeacially, when the molecular weight of MPEGMAA was 475(repeat unit of ethylene oxide=l0), the degree of retardation was the highest of them. The surface tensions of PCA solutions were lower than that of water due to the effect of PEO chain, and also the pore size distribution of cement mortar was influenced by it. The pores in cement mortar with PCA at 28 days were macropores in the range of 7 to 370$mu extrm{m}$, and accordingly, the densities and compressive strengths of mortar were lower than those of OPC mortar.
