聚丙烯纤维化学接枝改性增强水泥基复合材料的界面结合  

Surface modification of polypropylene fibers by chemical grafting methods to reinforce the interfacial bonding of cement-based composites

作　　者：李启金[1] 李国忠[1] 

机构地区：[1]济南大学材料学院建筑材料制备与测试技术山东省重点实验室,济南250022

出　　处：《复合材料学报》2013年第4期238-244,共7页Acta Materiae Compositae Sinica

摘　　要：以过氧化苯甲酰(BPO)为引发剂,采用二步化学接枝法对聚丙烯纤维进行接枝丙烯酸改性,利用正交分析法研究了引发温度、BPO浓度、接枝温度、接枝时间及丙烯酸(AA)浓度对纤维接枝率的影响,并评价了改性前后纤维与水泥基体的界面结合性能。结果表明:上述因素对纤维接枝率的影响大小为引发温度>BPO浓度>接枝时间>接枝温度>AA浓度,最佳反应条件为引发温度90℃,BPO 4.50×10-2 mol/L,接枝时间60min,接枝温度75℃,AA 1.4mol/L,此时纤维接枝率达13.12%;经化学接枝改性后,聚丙烯纤维表面亲水性和粗糙度增大,与水泥基体的界面结合得到增强,纤维掺量为0.05%(体积分数)时,聚丙烯纤维增强水泥砂浆的抗开裂性能比增大了26.6%,抗塑性收缩开裂性能显著增强。With benzoyl peroxide （BPO） as initiator, the surface of polypropylene （PP） fibers was modified with acrylic acid by two step-chemical grafting methods. The effects of initiation temperature, concentration of BPO, grafting temperature, grafting time and concentration of AA on the grafting degree of PP fibers were studied with orthogonal analysis method, and the interfaeial bonding between cement matrix and PP fibers before and after modification was evaluated. The results show that the influence of above factors on grafting degree of PP fibers in order is initiation temperature〉concentration of BPO〉 grafting time 〉 grafting temperature 〉 concentration of AA. The optimum reaction conditions are as follows： initiation temperature is 90 ~C, concentration of BPO 4.50 X 10 2 mol/L, grafting time 60 min, grafting temperature 75 ℃ and concentration of AA 1.4 mol/L. Under this condition, the grafting degree of PP fibers is 13. 12%. Though two step-chemical grafting modifications, the surface hydrophilicity and roughness of PP fibers are increased, so that the interfacial bonding between PP fibers and cement matrix is enhanced. When the volume fraction of modified PP fibers is 0.05 %, the cracking-resistance ratio of PP fibers reinforced cement mortar increase by 26.6 %, which indicate its plastic shrinkage cracking resistance is significantly enhanced.

关 键 词：聚丙烯纤维 化学接枝改性 水泥基复合材料 界面结合 抗塑性收缩开裂 

分 类 号：TB332[一般工业技术—材料科学与工程]