Utilization of copolymer based on poly (vinyl alcohol) and 2-ethylhexyl acrylate as admixture for cement pastes

Abstract

In this study, three composition ratios of [polyvinyl alcohol (PVA)-2-ethylhexyl acrylate (2-EHA)] were prepared by grafting polymerization techniques in aqueous solution using ammonium persulfate as free radical initiator. The ratio of PVA/2-EHA in the grafted copolymers was variable: 1/ 8, 1/ 6 and 1/ 4, respectively. The obtained grafted copolymers were characterized by different techniques including FTIR, 1 H NMR, TGA and DSC. The copolymers were mixed with cement to study the physicomechanical properties of cement pastes including W/C ratios, setting time, workability, water absorption as well as compressive strength were investigated. The results showed that the addition of grafted copolymers to cement pastes affected the physicomechanical properties. As the content of 2-EHA in the grafted copolymers increased, the water of consistency decreased, whereas the setting times (initial & final) were shortened. The compressive strength of the cement pastes was increased at all ages of hydration while water absorption decreased with increasing 2-EHA.

Utilization of Poly(Polyvinyl Alcohol-g-2-Ethylhexyl Acrylate) as Admixture for Mortar

“…The grafting polymerization in presence of APS, including the initiation, propagation, and termination steps, is shown in Scheme 1. The preparation of the copolymers and the method of analysis (FTIR, 1 H NMR, DSC, and TGA) follow those reported by Negim et al (2019).…”

“…The properties of the obtained grafted copolymers and the physical and mechanical properties of the pastes mixed with copolymers have been investigated by Negim et al (2019). It was observed that the thermal stability and transition glass temperature (Tg)of the copolymers are directly proportional to the amount of 2-EHA and that the copolymers are miscible because only one Tg was found.…”

“…PVA is modified by grafting vinyl monomers onto PVA using free radicals. Some previously used vinyl monomers are 2-hydroxy hexyl acrylate (Negim et al, 2019), acrylic acid and acrylamide (Singh & Rawat, 2013), and styrene (Koohmareh et al, 2011). Negim et al (2019) synthesized a copolymer by grafting 2-EHA on PVA using APS as a free-radical initiator and subsequently found that the properties of the cement improved with increasing the 2-EHA/grafted copolymer ratio.…”

“…Some previously used vinyl monomers are 2-hydroxy hexyl acrylate (Negim et al, 2019), acrylic acid and acrylamide (Singh & Rawat, 2013), and styrene (Koohmareh et al, 2011). Negim et al (2019) synthesized a copolymer by grafting 2-EHA on PVA using APS as a free-radical initiator and subsequently found that the properties of the cement improved with increasing the 2-EHA/grafted copolymer ratio. Negim et al (2014Negim et al ( , 2016 investigated the physico-mechanical properties of mortar containing the following cosurfactants: 2-wt.% dodecyl benzene sodium sulfonate (DBSS) and either 1.5-wt.% PVA or 1.5-wt.% polyoxyethylene glycol monomethyl ether (POE) as an air entraining agent.…”