Iranian Journal of Chemical Engineering (IJChE)

Abstract The goal of this study was to examine the morphology and characteristics of a blend of polylactic acid (PLA) with thermoplastic corn starch (TPS) and polyethylene glycol (PEG-400) using the extrusion process. The blends were evaluated through the tensile and impact strength tests, scanning electron microscopy (SEM), and X-ray diffraction (XRD) analysis. The experimental design method was selected to quantitatively analyze the influence of the content of TPS and concentration of the plasticizer on mechanical properties. Results from the tensile test showed that the addition of PEG-400 decreased tensile strength and elastic modulus, but increased elongation at break and impact strength, significantly. The blend with 20% TPS and 20 phr PEG-400 had the best overall performance in terms of tensile strength, elastic modulus, elongation at break, and impact strength. The SEM analysis indicated increased incompatibility and phase separation in samples with 40% TPS. Additionally, at high concentrations of PEG-400, the excessive plasticizer caused polymer saturation, resulting in unabsorbed plasticizer and phase separation. The findings suggest that the blend with 20% TPS and 20 phr PEG-400 could be suitable for use in eco-friendly applications.

Abstract The aim of this study was to improve the adhesion performance of plasticized polyvinyl chloride (PVC) coatings on steel substrates by using nanoparticles. For this purpose, the PVC plastisol with different concentration of nano-silica was prepared and applied to bond steel joints. The adhesive strength of the joints was determined by single-lap shear test. Moreover, mechanical properties and microstructure of coating were investigated. The addition of 1wt% nano-silica to plastisol dramatically increased the lap shear strength up to 4-fold, which was an outcome of compatibilizing effect of silica. Young's modulus and tensile strength of plasticized PVC were slightly increased by adding nanoparticles, as well. The scanning electron microscopy (SEM) and atomic force microscopy (AFM) exhibited higher inclusion size in the coating having higher silica volume which was attributed to the agglomeration of nanoparticles. In the following, the effect of plasticizer composition on the adhesion strength by replacing some part of dioctyl phthalate (DOP) plasticizer with more polar oil, epoxidized soybean oil (ESO), was examined. Although adding ESO improved the lap shear strength of the neat coating, its effect on the properties of the coatings containing silica was negligible.