Polyurethane elastomer–silica hybrid films based on oxytetramethylene soft segments: thermal and thermo-mechanical investigations

Abstract

An isocyanate-terminated polyoxytetramethylene (IPOTM; MW-\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\stackrel{-}{MW}$$\\end{document} = 1350 g/mol) was used to modify silica nanoparticles (SNPs). The nanoparticles were spherically coated by an organic shell consisting of the polyether material with 55% by weight, according to thermogravimetric analysis (TGA). IPOTM diisocyanate, as a telechelic prepolymer, was also used for the preparation of polyurethane elastomers (PUEs) through polyaddition reactions with 1,4-butane diol in the presence/absence of IPOTM-modified SNPs. The elastomers were characterized by Fourier-transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), and field emission-scanning electron microscopy (FE-SEM). Despite the use of the low amounts of the organically modified filler (5.0 and 7.0 wt.% of OSNPs), a significant enhancement in the storage and loss moduli (E and E values) of the elastomeric films could be occurred. Also, according to the tan δ vs temperature graphs obtained from dynamic mechanical analysis (DMA), the IPOTM-modified SNPs led to a little decrease, up to 5°C, in the glass transition temperatures (Tg values) of the elastomers. In addition, TGA thermograms showed that no reduction occurred in the thermal stability of the elastomeric polyurethanes after the addition of IPOTM-modified nanoparticles.