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In this article, the influence of fumed silica nanofiller on the structure and properties of segmented polyurethane elastomer (PUR) was investigated. In order to investigate the interactions at the filler-matrix interface, nonmodified and commercially modified fillers (with methacrylsilane and octylsilane) were used. The PUR composites with 1.0, 2.0, 4.0, 6.0, and 9.0 vol % of all fillers were prepared by solution casting method. Surface free energy of the fillers and polymer matrix was determined using contact angle measurements with different testing liquids. Change in morphology was analyzed using optical polarization microscopy and distribution of the filler in polymer matrix using scanning electron microscopy. The influences of silica fillers on mechanical and thermal properties of PUR were investigated. Results showed that sur-face treatment of silica filler with methacrylsilane and octylsilane reduces the agglomeration of particles that improves dispersion at microlevel. Addition of all fillers disrupts spherulite morphology and decreases crystallinity of the PUR matrix. Nonmodified silica nanofiller has the least pronounced influence on spherulite morphology and the lowest influence on polyurethane crystallinity and thus the best mechanical properties. Surface modification of silica with octylsilane has less influence on polyurethane crystallinity and on decreasing of mechanical properties than modification with methacrylsilane. V C 2011 Wiley Periodicals, Inc. J Appl Polym Sci 125: E181-E190, 2012

Polyurethane (PU) and poly(vinyl acetate) (PVAc) are partially miscible polymers. The aim of this study was to investigate the influence of untreated and surface pretreated calcium carbonate (CaCO3) on the interphase properties of PU/PVAc polymer blends with possible compatibilization effects when the conditions of effective adhesion are achieved. With the aim to modify interface between filler and matrices, CaCO3 was pretreated by grafting PVAc on the filler surface using 60Co γ‐ray irradiation polymerization of vinyl acetate. A series of the PU/PVAc blends without and with the addition of CaCO3 were prepared using a Brabender plasticorder at 140°C. Surface characterization of the PU and PVAc polymers as well as the untreated and surface pretreated CaCO3 fillers was carried out by determination of the surface free energy. The adhesion between CaCO3 and phases in the polymer blends was predicted on the basis of the calculated adhesion parameters (interfacial free energy, spreading coefficient and work of adhesion) obtained from the surface free energy of components. Thermal and mechanical properties were investigated by tensile strength measurements and differential scanning calorimetry (DSC). The adhesion parameters were correlated with the mechanical and thermal properties as well as phase morphology observations. POLYM. ENG. SCI., 2008. © 2008 Society of Plastics Engineers

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In this study influence of monomer ratio, butyl acrylate (BA), and methyl methacrylate (MMA) as well as silica nanofiller morphology (pyrogenic and colloidal) and concentration on the emulsion particle size distribution and properties of polyacrylate film (PA) synthesized by in situ emulsion polymerization were investigated. The ratios of the monomers BA/MMA were 100/0, 70/30, 50/50, 30/70, 0/100 and the filler concentration 0–10.0 mass%. PA nanocomposite films were characterized by using thermogravimetric analysis, differential scanning calorimetry, and tensile test. Research has shown that monomer ratio has significant influence on glass transition temperature (Tg). The addition of both types of silica filler, pyrogenic and colloidal, has no effect on Tg. Thermogravimetric analysis showed that systems with higher BA fraction have better thermal stability than systems with higher MMA fraction. Addition of the both type of silica nanofiller enhanced thermal stability of PAs, however, systems with colloidal silica are more stable. Pyrogenic silica and higher amounts of colloidal silica nanofiller increased PA emulsion particle size up to several micrometers. Addition of higher amounts of colloidal silica improved mechanical properties compared to the neat PA matrix. POLYM. ENG. SCI., 53:2292–2298, 2013. © 2013 Society of Plastics Engineers

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The interface in particulate filled polymer systems determine to a large extent, the mechanical and morphological properties of composites and polymer blends. The present contribution describes surface free energy measurements and calculations of adhesion parameters at the interface in poly(vinyl acetate) (PVAc) and polyurethane (PU) composites as well as in styrene acrylonitrile/ethylene propylene diene monomer (SAN/EPDM) blends filled with calcium carbonate (CaCO3) nanofillers. The effects that a surface pretreatment of the filler with either silane or stearic acid had on the interface been investigated and related to the resulting properties of the composites and filled polymer blend. The optimal adhesion in the particulate composites and blends was determined by the minimal interfacial energy and optimal coefficient of wetting. The conditions of the optimal adhesion with filler location at the interface, predicting by the thermodynamical models, correlated well with the improvement of the morphological and mechanical properties. POLYM. ENG. SCI., 2008. © 2008 Society of Plastics Engineers.

In this work we have investigated the effects of CaCO 3 nanofiller pretreatment on the properties of polyurethane (PU) composites prepared by a mixing procedure. The aim was to enhance interactions at the matrix/filler interface and to improve the distribution of the filler in the polyurethane matrix. CaCO 3 nanofiller was treated with two different functional trialkoxysilanes, viz. γ-aminopropyltriethoxysilane (AMPTES) and γ-glycidoxypropyltrimethoxysilane (GPTMS). Fourier transform IR spectroscopy of the pre-treated CaCO 3 surface indicates that AMPTES formed a high-molecular-weight ladder-type structure on the CaCO 3 surface, while GPTMS was adsorbed in the form of a lower-molecular-weight oligomeric structure. Increased ultimate tensile strength and elongation were obtained for PU + CaCO 3 nanocomposites with silane pre-treated filler. This can be explained as the consequence of better stress transfer through the composite, observed on scanning electron micrographs, due to an improved adhesion between PU matrix and silane-treated fillers. The reinforcement effect is more pronounced for PU composites with aminosilane-treated CaCO 3 filler in comparison to filler treated with glycidoxysilane.