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碳纳米管(MWCNT)在水性体系及水泥基体中的分散性直接影响MWCNT增强水泥基复合材料(MCNTRC)的宏观性能。本文以萘系磺酸盐甲醛缩合物(FDN)、甲基纤维素(MC)、十六烷基三甲基溴化铵(CTAB)三种表面活性剂(SAA)单独或复合作为MWCNT的水性分散剂,探讨MWCNT的分散效果;借助物理超声波分散和化学CTAB分散,混合浇筑法制备了六组不同掺量MWCNT的MCNTRC,之后对MCNTRC试件的抗折及抗压强度测试,断口SEM观察和能谱分析。结果表明:只有CTAB在w(CTAB):w(MWCNT)为1~3范围时对MWCNT分散效果最好;少量的MWCNT可较好地分散于水泥基体中,并发挥一定的桥联增韧作用,MCNTRC的抗折、抗压强度最高可分别提高17.0%、28.3%;相应SEM图也显示MWCNT在基体中分布均匀,两者结合界面良好。
The dispersibility of MWCNTs in aqueous systems and cementitious substrates directly affects the macro performance of MWCNT reinforced cementitious composites (MCNTRCs). In this paper, three kinds of surfactants (SAA), such as naphthalene sulfonate formaldehyde condensate (FDN), methyl cellulose (MC) and cetyltrimethylammonium bromide (CTAB) Disperse agent to investigate the dispersion of MWCNTs. Six kinds of MCNTRCs with different MWCNTs were prepared by means of physical ultrasonic dispersion and chemical CTAB dispersion. The flexural strength and compressive strength of MCNTRC specimens, fracture SEM observation and Energy spectrum analysis. The results show that only the CTAB has the best dispersing effect on the MWCNTs when the CTAB: w (MWCNT) is in the range of 1 to 3; the smaller amount of MWCNT can be well dispersed in the cement matrix and exert some bridging toughening effect The flexural strength and compressive strength of MCNTRC can be increased by 17.0% and 28.3% respectively. The corresponding SEM images also show that the MWCNTs are uniformly distributed in the matrix, and the bonding interface between the two is good.