Preparation Of Polyether Polycarboxylic Acid Water Reducer And Its Adaptability To Cement

Polycarboxylic acid superplasticizer has the molecular designability of main chain and side chain structure with more possibilities for further performance optimizing which has become a hot spot in the field of high-performance water reducer.However,the adaptability of polycarboxylic acid water reducer and cement reduces its water reducing effect and performance.In view of the adaptability of water reducer,this paper designed and synthesized two kinds of polycarboxylic acid water reducer with side chain polyether,studied the adaptability of water reducer and cement,and proposed the action mechanism of improving the adaptability of water reducer and cement,The main work and conclusions obtained are as follows:Polyether type polycarboxylic acid water reducer polymerized by polyisobutenol polyoxyethylene ether-acrylic acid(mpeo-maa)monomers and polyether type polyether water reducer copolymerized by polyisobutenol polyoxyethylene ether-acrylic methyl-maleic acid(mpeo-maa-ma)terpolymers were prepared.The optimum reaction conditions for the synthesis of two water reducers were founded.The solid content of water reducer is close to the theoretical value,and the thermal stability is good.When the content of mpeo-maa and mpeo-maa-ma superplasticizer is 0.6wt.%,the initial net pulp fluidity above 290mm can be obtained,and the fluidity above 210mm can be retained after 60min,and the loss of fluidity is small.Benchmark cement,ding xin cement and song village cement water reducing agent showed high water reducing rate,and MPEO-MAA-MA jianshuiji net in the three different cement paste fluidity and expand the degree of deviation is lower,not affected by cement brand,show better water reducing effect,showed relatively second monomer water reducing agent,the synthesis of polyether type three poly carboxylic acid water reducing agent and the better adaptability of cement.Water reducer improved the flexural strength and compressive strength of cement mortar samples at 3d,7d and 28d.Compared to commercially available poly carboxylic acid water reducing agent,polyether type poly carboxylic acid water reducing agent of concrete has a good adaptability,have the characteristics of the liquid concrete,join MPEO-MAA and MPEO-MAA-MA water reducing agent of concrete compressive strength are higher than commercially available water reducing agent of concrete mixing,description of the preparation of polyether type poly carboxylic acid water reducing agent has good water retention and overall performance,are the basic conditions of application in practical engineering.The mechanism of the synthesized polyether polycarboxylic acid superplasticizer was as follows:Comb polyether polycarboxylic acid superplasticizer-COO~-repulsive action of the same charge makes the cement particles easy to disperse hydrocarbon molecular chain polyether molecular side chain to form a comb solvation layer,hinder the cement particles close contact,prevent the formation of flocculation structure,thus increase the lubricity and plasticization ability,improve the water reducer and cement adaptability.