Preparation and applications of hydrophobic multicomponent based redispersible polymer powder: A review

摘要

The main aim of the present review is to show the effect of redispersible (RD) powder which is hydrophobic multicomponent based polymer added to various cementitious compositions. The paper gives an insight into different polymer based admixtures, their interaction with Portland cement, methods adapted for preparation of RD polymer powder and their latex. This polymer powder has proved to improve abrasion resistance, water resistance, adhesion, flexibility of mortars that contain hydraulic binders due to its particular physical and various chemical compositions. The paper highlights the influence of hydrophobic RD polymer powder in plaster mortars based on cement. By optimizing the traditional recipes, cement mortars with improved mechanical-physical properties are obtained and characterised. RD polymer powders are prepared by spray drying process in which polymer emulsions are converted into powder form at various parameters such as high temperature and pressure etc. The dispersion powders are suitable additives for hydraulic binders in construction material industry. This kind of production is also used as binders in coating or adhesive compositions. RD polymer powders are used in tile adhesives, external wall putty, construction adhesives, building binders, joint mortars, plasters, filling compositions such as floor filling compositions, concrete repair joints, water proofing membrane applications and crack isolation membrane. So the different varieties of RD polymer powder are prepared from different compositions for improvement in properties. RD powder based on a film forming polymer and at least one water soluble compound have anti sticking property and have improved redispersible property. RD powder having non-blocking, water soluble polymeric substance with copolymer of vinyl acetate and water soluble alkali metal or alkaline earth metal salts are also available which are free-flowing, readily redispersed in water and mainly used in gypsum, cement, mortar etc. There are various kinds of RD powder with their unique properties based on wide range of polymer latex such as copolymer of ethylene vinyl acetate (EVA), terpolymer of ethylene/vinyl chloride/vinyl laurate (E/VC/VL), terpolymer of vinyl acetate/ethylene/vinyl ester of versatic acid (VAc/E/VeoVA), acrylate copolymer, Polyvinyl acetate (PVAc) polymer, Styrene Butadiene Rubber (SBR) etc. Today the demand of only cement, concrete and mortars have decreased day by day for building materials because they show disadvantages due to natural effects: low bonding strength, low tensile strength and low chemical resistance etc. Modern additives and admixtures are used to solve these disadvantages. To overcome these problems, RD powder attracts the attention of many researchers due to their unique physical and chemical properties. So RD powder is incorporated into cementitious composition that contributes to enhanced durability and mechanical properties of cementitious compositions. The product is majorly used in construction industry for enhancing key properties of cement based formulations. With the global major trend urbanisation, insistence for high -rise construction and building starts to increase. This serves the requirement for efficient performance and better waterproofing system for chemical market in construction and building area. With different base materials, RD powder can enhance the properties of mortar, bonding strength, compressive strength, abrasion resistance, water resistance, water retention, toughness and constructability. (C) 2020 Elsevier Ltd.All rights reserved.