Abstract
PurposeThe purpose of this paper is to prepare stabile emulsions with 0–15% of colloidal silica and high monomer/water ratio and to investigate the influence of silica addition and surface modification on the polyacrylate properties.Design/methodology/approachImproving the properties of the composite can be achieved by optimizing the compatibility between the phases of the composite system with improving the interactions at the matrix/filler interface. Therefore, the silica surface was modified with nonionic emulsifier octylphenol ethoxylate, cationic initiator 2,2'-azobis-(amidinopropane dihydrochloride) and 3-methacryloxypropyltrimethoxysilane and polyacrylate/silica nanocomposites were prepared via in situ emulsion polymerization. Particle size distribution, rheological properties of the emulsions and morphology, thermal properties and mechanical properties of the film prepared from the emulsions were investigated.FindingsPolyacrylate/silica systems with unmodified silica, silica modified with nonionic emulsifier and cationic initiator have micrometer, while pure PA matrix and systems with silica modified with silane have nanometer particle sizes. Addition and surface modification of the filler increased emulsion viscosity. Agglomeration of silica particles in composites was reduced with silica surface modification. Silica filler improves thermal stability and tensile strength of polyacrylate.Originality/valueThis paper provides broad spectrum of information depending on filler surface modification and latex preparation via in situ emulsion polymerization and properties with high amount of filler and monomer/water ratio with the aim that prepared latex is suitable for film formation and final application.
Highlights
Properties of the polymer matrix and the shape and size, specific surface area, packing, surface activity and distribution of the filler in matrix, as well as interactions of the filler with polymer matrix have significant effect on the composite properties
3.1 Particle size distribution Particle size distributions (PSDs) of PA1silica emulsions are shown on Figure 1
According to previous findings [LunaXavier et al, 2001 in systems with untreated silica filler encapsulation of silica particles with polymer is possible if potassium persulfate, KPS is used as the initiator
Summary
Properties of the polymer matrix and the shape and size, specific surface area, packing, surface activity and distribution of the filler in matrix, as well as interactions of the filler with polymer matrix have significant effect on the composite properties. The strength of interactions can be modified by filler pretreatment with different surface modifiers. Nanocomposites can be prepared by mixing of the filler and polymer matrix or by in situ. Better dispersion and distribution of the filler in polymer matrix can be achieved by in situ polymerization (Hashemi-Nasaba and Mirabedini, 2013; Kazakova et al, 2018; Motaung et al, 2017). For the application of suspensions and emulsions in products such as paints, cement, color printing, liquid adhesives, sealants, cleaning products and food rheological properties are very important. As the polyacrylate emulsions (PA) could be
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