The influence of camphorquinone on the photochemical stability of cellulose

Abstract

The photochemical stability of pure cellulose fibres and cellulose fibres with camphorquinone (CQ) has been studied by Fourier transform infrared spectroscopy (FTIR), thermogravimetry analysis (TG), derivative thermogravimetry (DTG) and differential scanning calorimetry (DSC). The initial decomposition temperature T o, temperature of the maximum rate of the process T max and specific enthalpy Δ H were higher for cellulose fibres before UV irradiation than for those UV irradiated in either N 2 or air. The weight loss was higher for the samples after UV irradiation. In the presence of CQ the initial decomposition temperature T o for cellulose fibres was the same before and after UV irradiation, but much lower than for pure non-irradiated cellulose fibres. The specific enthalpy of the process is much lower after UV irradiation. The weight loss was smaller for the samples with CQ than for pure cellulose fibres. Comparison of the shape of the derivatographic, DSC and FTIR curves before and after UV irradiation suggests that photodegradation of cellulose occurs during irradiation of this biopolymer and that this process is faster in the presence of camphorquinone (CQ). The camphorquinone is photo-excited by UV light to the reactive triplet state and causes more efficient photodegradation of the cellulose.