Hydrohypropyl cellulose/polyurethane blends. The behavior after accelerated ageing. a ftir study

Abstract

A series of hydroxypropyl cellulose/polyurethane blends (PU_HPC 20/80, PU_HPC 50/50 and PU_HPC 80/20) were investigated by FT-IR spectroscopy after exposure to simulated ageing conditions (UV irradiation, 40 °C and 60% humidity) for 600 h. The degree of structural organization was analyzed through quantitative determination of the crystallinity indexes: total crystallinity index (TCI), lateral order index (LOI) and the hydrogen bond intensity (HBI), as well as by the evolution of the “ordered”, “disordered” and “free” areas in the carbonyl (1600-1800 cm-1) spectral region. The accelerated weathering conditions determined structural modification in the PU_HPC blends in correlation with their composition and the exposure time, both polymeric components being affected by the hydrolysis and oxidation processes.