Synthesis And Performance Of Polycarboxylate-alcohol Amine Cement Grinding Aids

Polycarboxylate, synthesized by polymers, is a kind of surface active agent that mainly used in the field of concrete admixture. The substance has the feature of low mix amount, high water-reducing rate and dispersity, green environmental protection, and the effect of grinding aid at the same time, resort to which could be used in the grinding cement powder. At present, most of the liquid grinding aid popular in the market is synthesized by a single or composite product derived from the chemical staff, such as alcamines and alcohol. A better grinding effect could be available, however, a higher cost price and a bad performance stability, at the same time, should be accepted. Such a grinding aid described above therefore couldn’t totally meet the need of diversification and high levels. In the future, the research of efficient and low-cost grinding aid will surely be focused on the point of macromolecular synthesis technology.The molecular design could be carried out, combined with the characteristics of polycarboxylate molecular structure and its mechanism of action after investigating and summarizing the application status and synthesis methods of the polycarboxylic acid technology admixture domestic and abroad. The alcohol amine, with functional gene, owing the grinding effect could be fitted together with the main chain of polycarboxylate by macromolecular synthesis and then two kinds of new polycarboxylate-alcohol amine could be available.In our present work, the small monomer M is synthesized by the esterification of maleic anhydride and triethanolamine. The M and maleic anhydride were then added into allyl polyethenoxy ether to produce C3-polycarboxylate-alcohol amine type cement grinding aid by aqueous solution polymerization, under the initiating effect of ammonium peroxydisulfate. The experiment was carried out by changing a signal factor to explore the effect of different factor on the copolymerization and finally to pick up the optimal synthesis conditions for the technology.The big monomer prenyl polyoxyethylene ether was freely radical copolymerized with the small monomer methacrylate, sodium methallyl sulfonate, and functional monomer triethanolamine in aqueous solution to produce G4-polycarboxylate-alcohol amine type cement grinding aid. The optimizing technological conditions could be available by investigating the factors, such as the monomer mole ratio, initiating agent type and amount, polymerization inhibitor usage, polymerization temperature, feeding mode and reaction time.Aqueous phase gel chromatography and infrared spectrometer were used to determine the structure of polycarboxylate-alcohol amine cement grinding aid. A laboratory mill of two kinds of self-made grinding aid was carried out, after which the screen residue value, surface area, cement particle grain diameter distribution and scanning electron microscope of the finished cement were measured to investigate the grinding performance.The cement sample, mixed with self-made grinding aid after milled, was studied by measuring its standard consistency water usage, time of coagulation, cement stability and strength of mortar and analyzing the effect of the grinding aid addition on the performance to investigate its compatibility with water.