Synthesis and properties of cellulose based copolymer polycarboxylate superplasticizer
The cellulose based copolymer polycarboxylic acid water reducer(HEPCEs)was prepared from natural fiber by grafting etherification,nucleophilic substitution and free polymerization.The molecular structure of synthetic HEPCEs was analyzed by infrared spectrum and gel permeation chromatography.The performance of HEPCEs was tested from the aspects of paste fluidity and time varying fluidity.The mechanism of action of HEPCEs on cement slurry by testing molecular particle size,zeta potential and adsorption layer thickness was further investigated.The results showed that the suitable substitution amount of modified cellulose polyether DBHECs in HEPCEs was 5％-10％.Excessive substitution of DBHECs would lead to branch chain entanglement and hindering the anchoring of carboxylic acid groups,causing a decrease in the performance of the water reducing agent.The introduction of appropriate substitution of cellulose structure can effectively further improve the performance of water reducing agents while maintaining good adsorption performance.From experiments with time variation,HEPCEs-5 indicated good performance and exhibited a certain degree of sustained release effect.
cellulose polyethermodifiedbio-basedpolycarboxylate water reducing agentfree radical copolymerization
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