聚合工艺对聚羧酸高性能的影响.doc

聚合工艺对聚羧酸高性能的影响 In recent years, large-scale engineering construction such as Bridges, highways, high-rise building more and more high to the requirement of concrete, the growing demand for high performance concrete. The polycarboxylic acid series high performance dewatering agent is an important part of high performance concrete and is becoming more and more concerned. Series of poly (carboxylic acid high performance water reducing agent is polymer grafted copolymer, the current domestic manufacturers sprang up, and its production process, raw material type and foreign large difference, the quality of the product also has a large gap. Therefore, in this paper, by analyzing the domestic and foreign patents, the polymerization process has carried on the system design and experiment, the different synthesis process effect on the properties of poly (carboxylic acid water reducing agent are discussed in this paper. At present, the main monomer of the synthesis polycarboxylic acid series of high performance dewatering agent is methoxy polyethylene glycol (MPEG) and allyl polyethylene glycol (XPEG) etc. Synthesis process has many patents for its products both at home and abroad related introduction [1-2], synthesis methods about the following kinds: (1) one-time charging method: to a certain proportion of the reaction of monomer and initiator one-time join reactor, heating up to the specified temperature thermal reaction after a certain time, poly carboxylic acid neutralization reactant obtained water reducing agent products; (2) drops addition: mix reaction monomer mixture solution, mixture solution, at the same time the initiator were inserted in the dropping funnel according to certain speed drops to join a certain amount of water in the reactor, add finished, thermal reaction time, temperature and get water reducing agent products; (3) the reaction monomer is added at once, the initiator solution is added or added in batches, the temperature is heated up to a certain t