Modified Vinyl–POSS Materials as Sun Protection Factor and as Films for Greenhouse Cover

Abstract In this work, modified vinyl–[polyhedral oligomeric silsesquioxane (POSS)] (VP) materials as sun protection factor and as films for greenhouse cover to protect from ultraviolet (UV) were explored. Based on VP and modified with various amounts of tetraethoxysilane (TEOS), POSS-modified films f–VPT i wt-% were prepared. The average transparency (AT) of the films measured at the ranges of UV–A (320–400 nm) and the UV–B (280–320 nm) spectra was about 45.43–48.71%, indicating that these films can provide a physical barrier to block UV–A and UV–B absorptions (causing human skin cancer and damaging photosynthesis of plants) by the skin and by plants in a green house. The under 25 wt–% TEOS additions result in the hybrid structure containing SiO2 which causes an increase in the AT radiation from sunlight. This increase tendency was validated using calculations of the density of state and the energy–band structure of both VP and SiO2 building blocks by the Materials Stutio software. The less transparency of VP can be ascribed to its much narrower forbidden band. Keywords: Polyhedral oligomeric silsesquioxane (POSS)tetraethoxysilane (TEOS)ultravioletdensity of statesenergy–band and structure Acknowledgments This work was supported by the Science and Technology Bureau of the Government of Harbin City (Grant No. 2007AA4BG139), China. We also acknowledge support by the School of Chemical Engineering and Materials, Harbin University of Science and Technology, China, for most of the calculations.