Investigation of poly(butyl acrylate-co-methyl methacrylate) nanocomposite film properties and its uses as paint binder

Poly(butyl acrylate-co-methyl methacrylate) (poly(BA-co-MMA) is a copolymer used as a binder in coating materials, lacquers and glue-like materials by means of to its good film forming properties. Generally, for two decades, many studies have been devoted to nano-reinforcement addition into polymers for improving features of polymer films. In this study first of all poly(BA-co-MMA) was synthesized in order to be used as binder in water based road marking paint. The synthesis of the copolyme rwas conducted by semi batch emulsion polymerization. Necessary conditions were determined in order to synthesize copolymer with intented glass tarnsition temperature and molecular weight. In the later stage of the study, different nano additives were added to hte Water based binder. • Na-Montmorillonite (Na-Mt) was obtained by purificaion of sodium bentonite available from Resadiye. Poly(BA-co-MMA) nanocomposite synthesis was achieved with Na-M contents ranging between 1-3 %. Nanocomposites having 47 % solids content were obtained via semi batch in-situ emulsion polymerization. For comparison, nanocomposite having 35 % solids content and nanocomposite, which was prepared by direct blending of Poly(BA-co-MMA) and Na-Mt, were synthesized (blend process). • Na-Mt was modified with five different quaternary ammonium salts and organo-montmorillonites (O-Mt) were formed. By using these O-Mts poly(BA-co-MMA) nanocomposite was synthesized via semi batch in-situ emulsion polymerization. Differing from other studies, in this thesis O-Mt was used in suspension form for nanocomposite synthesis directly after the modification of Na-Mt. By this way, water based O-Mt nanocomposites with 47 % solids contents were obtained via emulsion polymerization. Like Na-Mt nanocomposites, also an O-Mt nanocomposite having 35 % solids content was synthesized and an O-Mt nanocomposite was prepared by blend process for comparison. • Nanocrystalline cellulose (NCC), which was obtained by acid hydrolysis of microcrystalline cellulose (MCC), was used as an additive in poly(BA-co-MMA). NCC based nanocomposites were prepared by blend process. NCC ratio varied between 1-3 % and solids content of the nanocomposite was 35 %. Size distributions, molecular weights, glass transition temperatures of Na-Mt, O-Mt and NCC based nanocomposites were determined, X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), infrared spectroscopy (FTIR), thermal gravimetric analyses were performed mechanical properties were investigated by mechanical tests. According to these characterization and tests, it was found out that montmorillonite additives improved copolymer properties. However it was realized that O-Mts showed higher affinity towards poly(BA-co-MMA) than Na-Mt. Especially mechanical properties of NCC based nanocomposites highly improved. Tensile strength of montmorillonite based nanocomposite increased 187.5 % while tensile strength of NCC nanocomposite increased 262.5 %. With the idea of obtaining optimum values, 1.5 % NCC and 1.5 % Na-Mt were also added to poly(BA-co-MMA). Finally, water based road marking paints were prepared in which pristine copolymer and montmorillonite reinforced copolymers were used as binders. These road marking paints were in the limits of the General Directorate of Highways standards according to the dye tests of hiding power solid dry time, no pick up time, abrasion resistance and chromaticity coordinates. Although montmorillonite enhanced latex film properties, no effect was observed in the properties of paint which had been produced by using montmorillonite based nanocomposite as binder.