Investigating the crosslinking effects on surface characteristics of vinyltrimethoxysilane-grafted moisture-cured low-density polyethylene/ethylene vinyl acetate blend

摘要

In this article, the adhesion attributed characteristics of vinyltrimethoxysilane-grafted moisture-cured low-density polyethylene/ethylene vinyl acetate (VTMS-grafted LDPE/EVA) blend have been investigated before, during, and after crosslinking process. Characterization of the changes due to the moisture-induced crosslinking has been carried out as a function of vapor exposure (crosslinking) duration. Fourier transform infrared (FTIR) spectroscopy was used for identification of compounds based on functional groups and also for identification of any modification in the chemical structure of the compounds. In addition, contact angle measurement was performed to calculate the surface energy and its components. Scanning electron microscopy (SEM) and atomic force microscopy (AFM) were utilized to study the surface morphology changes. The results demonstrated that the moisture-induced crosslinking was not causing significant changes in roughness parameters and surface energy values of the samples after crosslinking. For instance, the R-a parameter, which shows the arithmetic average height of the surface, changed from 278 nm to 280 nm and the surface free energy decreased from 30.90 to 27.63 mJ/m(2) after 16 hours of vapor exposure. However, surface relative elastic modulus approximately doubled, indicating a stiffer surface. The findings confirmed that the adhesion-related surface properties of the VTMS-grafted LDPE/EVA blend were not affected impressively by the crosslinking. (c) 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 136, 47147.