Preparation of graft-modified polybutadiene latex and its application in cement matrix composites

Currently, the use of latex for conventional cementing shows a series of problems such as low salt resistance, poor freeze-thaw stability, bad toughening ability and poor integrated performance. In view of the above-mentioned facts styrene(St) as hard monomer and polybutadiene latex (PB) as seed soft monomer combine new type of functional monomer, were used to synthesize the latex HTL-100L by emulsion grafting polymerization method, which had the properties of heat resistance, salt tolerance, good freeze-thaw resistance and strong toughening ability. Microstructural analysis suggests that all monmers are participated in the reaction and and the HTL-100L is the target product. The molecular structure is stable at high temperature about 420℃. The performance test of HTL-100L portland cement matrix composites shows that HTL-100L significantly improves the toughness of pure cement whose elastic modulus decreases nearly 100% and the strength of portland cement stone developes well. it has the advantages of wide applicable temperature range(80-180℃), easily controlled system and good integrated performance. Thus, it can be applied to solve the problems in latex for conventional cementing and improve the comprehensive performance of oil well cement matrix composites.