Protection of high-density polyethylene-silicon composites from ultraviolet-visible photodegradation

Abstract

[EN] The extent of the ultraviolet¿visible (UV¿vis) photoirradiation effect on high-density polyethylene (HDPE) and HDPE¿sili-con (Si) composites is reported in terms of the addition of Si microparticles at contents of 0.1, 1, and 5 wt %. A standard acceleratedUV-vis exposure was applied over 2750 h, corresponding to 22 months in Florida. Thermogravimetry, differential scanning calorimetry,and Fourier transform infrared spectroscopy were used as reliable techniques for monitoring the quality of the HDPE-Si composites. Theincreasing addition of Si microparticles delayed the photodegradation of the HDPE¿Si composites. Because of their strong light-scattering effects, Si microparticles blocked the degradation of ter tiary carbons of the HDPE backbone and reduced the apparition ofvinyl groups; this prevented the structural impoverishment of HDPE-Si composites. Consequently, variations in the crystallization tem-perature (Tc) and melting temperature (Tm), which were indicators of photodegradation, were not modified. In general, the HDPE-Sicomposite formulation with 5 wt % Si microparticles was useful for protecting the material from photodegradation and, thus, should bean environmentally friendly, reliable alternative UV-vis blocker.