Preparation and properties of allyl ether-based polycarboxylate superplasticizer with short-branched chains modified by nano-silica

Abstract

The combination of nanoparticles and polycarboxylate ether superplasticizers is expected to simultaneously improve the durability and mechanical properties of mortar and concrete. However, the uniform dispersion of nanoparticles in cement materials has always been a difficult challenge. In this paper, nanoparticles are modified with surfactants to provide a research direction for better dispersion of nanoparticles in cementitious materials. Modified allyl ether polycarboxylate superplasticizer with short-branched chains was synthesized from acrylic acid and allyl glycidyl ether. Nano-silica/polycarboxylate ether was obtained by grafting nano-silica onto polycarboxylate ether molecular chains through intermolecular dehydration, thus achieving a homogeneous dispersion of nano-silica in the cementitious material. The results show that nano-silica/polycarboxylate ether has better dispersibility in cement matrix and strong clay resistance, which compensates for the poor dispersion of polycarboxylate ether synthesized from conventional polyethylene glycol graft chains in the presence of clay impurities.