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

摘要

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 tetraethoxy si-lane (TEOS), POSS-modified films f-VPT_(i vt.%) 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 SiO_2 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 SiO_2 building blocks by the Materials Stutio software. The less transparency of VP can be ascribed to its much narrower forbidden band.