Mechanical properties and surface morphology of photodegraded polyoxymethylene modified by a core-shell acrylate elastomer with UV stabilization

摘要

In order to improve the photostability of polyoxymethylene (POM), a core-shell acrylate elastomer with UV stabilization, i.e. poly[(methyl methacrylate)-(butyl acrylate)-2-hydroxy-4-(3-methacryloxy-2-hydroxypropoxy)benzophenone] (core-shell poly(MMA-BA-BPMA)), was added into the POM matrix using a melt-mixing method. The effect of the modification with core-shell poly(MMA-BA-BPMA) on POM was compared with that of poly(MMA-co-BA-co-BPMA) copolymer. Scanning electron microscopy, metallographic microscopy, Fourier transform infrared spectroscopy, differential scanning calorimetry. X-ray diffraction and X-ray photoelectron spectroscopy were employed to characterize POM blends before and after UV irradiation, and the mechanical properties of the POM blends were investigated. The results showed that core-shell poly(MMA-BA-BPMA) improved well the compatibility with and toughness of the POM matrix, and its light-stable functional groups could increase the UV resistance of POM blends. During UV aging, the impact strength and elongation at break of POM/core-shell poly(MMA-BA-BPMA) blends were retained, the growth rate of surface cracks of POM was inhibited effectively by core-shell poly(MMA-BA-BPMA) and the degree of photo-oxidation of POM blend surfaces was improved to a certain extent. Compared with poly(MMA-co-BA-co-BPMA), core-shell poly(MMA-BA-BPMA) had a better UV stabilization effect on the POM matrix. Our results indicate that the core-shell acrylate elastomer with toughening and UV stabilization functions can significantly improve the long-term UV stability of POM.