Miscibility improvement of LDPE/PVA blends by using silane-coupling agent

Mixing two polymers usually results in an immiscible system, characterized by a coarse, easy to alter morphology, and poor adhesion between the phases. These blends have large size domains of dispersed phase and poor adhesion between them. Therefore, miscibility of polymer blend must be improved by using suitable additives such as compatibilizer. In this study 5% of silane 3-(trimethoxysilyl)propyl methacrylate is used as compatibilizer to improve the miscibility and compatibility of LDPE/PVA blends. The samples were prepared by using a twin screw extruder. LDPE and PVA have been mixed with different weight proportion. Several tests were carried out to identify the compatibility and miscibility of the blends such as tensile properties, hardness, density, Fourier transforms infrared FTIR, digital microscope, scanning electron microscopy SEM and differential scanning calorimetry DSC. Result show that tensile strength, young modulus, elongation at break, density and hardness is increased with silane addition to the blends. SEM and digital microscope shows an improvement in the miscibility due to the better interaction between the two polymers as silane is added.

Calculation of Liquid–Solid Interfacial Free Energy in Pb–Cu Binary Immiscible System

Based on the solid–liquid interfacial free energy theory of the complex Warren binary & pseudo-binary system and through the simplification of it by taking Pb–Cu binary system as an example, the physical model for it in binary immiscible system can be obtained. Next, its thermodynamic formula is derived to obtain a theoretical formula that only contains two parameters, and comparisons are made with regard to γSL calculated values and experimental values of MPE (multiphase equilibrium method) under several kinds of temperatures. As manifested in the outcomes, the improved physical model and theoretical formula will become not only easy to understand but also simple for calculation (the calculated value of γSL depends on two parameters, i.e. temperature and percentage composition of Cu atom). It can be treated as the foundation of application for the γSL calculation of liquid–solid interfacial free energy in other immiscible systems.