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碳纤维增强水泥基复合材料(CFRC)是一种新发展起来的、很有潜力的功能材料。丙烯作前驱体,对短碳纤维在高温下(900~1300℃)进行100个小时左右的化学气相浸渍(CVI)表面处理,丙烯在高温下分解,生成热解碳,沉积在碳纤维表面。借助超声波预分散技术及新型分散剂羟乙基纤维素(hydroxyethyl cellulose,HEC)和超细颗粒硅灰的分散作用,实现了CVI处理碳纤维在水泥基体中的均匀分散。HEC水溶液的质量分数控制在1.56~1.77%之间为宜。分别运用扫描电镜法(SEM)、新拌料浆法(FM)、硬化试件电阻率测试法(ERM)及模拟试验法(SE)四种方法评价了CVI处理后短碳纤维的分散性。每种方法均有自身的优缺点和适应环境,四种方法中,模拟试验法(SE)是评价制备CFRC复合材料前期、碳纤维第一步分散的最方便的方法,此法不仅可节约时间和大量的原材料,而且可预测制备CFRC过程中应选择何种分散剂及碳纤维第二步分散的情况。
Carbon fiber reinforced cement-based composites (CFRC) is a newly developed and promising functional material. Propylene as precursors, the short carbon fibers were treated with chemical vapor impregnation (CVI) at high temperature (900 ~ 1300 ℃) for about 100 hours. The propylene was decomposed at high temperature to produce pyrolytic carbon, which was deposited on the surface of carbon fiber. The dispersion of CVI-treated carbon fibers in cement matrix was achieved by means of ultrasonic pre-dispersion technology and dispersion of new dispersant hydroxyethyl cellulose (HEC) and ultrafine silica fume. HEC aqueous solution mass fraction control between 1.56 ~ 1.77% is appropriate. The dispersibility of short carbon fibers after CVI treatment was evaluated by scanning electron microscopy (SEM), fresh slurry method (FM), hardened specimen ERM and SE. Each method has its own advantages and disadvantages and adapt to the environment, the four methods, simulation test (SE) is to evaluate the preparation of CFRC composite pre-carbon fibers, the first step of the most convenient method of dispersion, this method not only saves time and A lot of raw materials, but also predict the preparation of CFRC should choose what kind of dispersant and carbon fiber dispersion of the second step.