Photoinduced reaction of lyocell with water-soluble photoinitiator and multifunctional acrylate

Abstract

The photo-induced reactivity of lyocell fabrics containing two water-soluble photoinitiators and multifunctional acrylate was characterized by the UV absorption and photoluminescence properties. The relative quantum yields of the fluorescence and phosphorescence were analyzed at three exciting wavelengths and the proportional constants were compared. The fabrics containing [2-(acryloyloxy)ethyl](4-benzoylbenzyl)dimethylammonium bromide (PIA) and 1,3,5-triacryloylhexahydro-s-triazine (TAF) exhibited smaller relative quantum yields than the fabrics containing [3-(3,4-dimethyl-9-oxo-9h-thioxanthene-2-yloxy)-2-hydroxypropyl]trimethylammonium chloride (PIB) and TAF. The modified cellulose fabrics with tertiary amine also had smaller relative quantum yields than regular fabrics. We found that the cellulose/PIA/TAF system was a more photoactive process than the cellulose/PIB/TAF system and that the AM/PI/TAF system was more active than the regular/PI/TAF system. Furthermore, a TAF molecule was proved to have photo-reactivity with cellulose by a comparison between the proportional constants in the fluorescence quantum yields of PI/TAF solutions and cellulose/PI/TAF fabrics. These fabrics were irradiated by a high-power UV system with an electrodeless lamp. FTIR-ATR spectra showed that TAF molecules were successfully introduced to the surfaces of the irradiated fabrics. Thermogravimetric analysis showed that the thermal stability increased and the degree of thermal depolymerization decreased with the addition of PI and TAF; therefore, it was inferred that TAF molecules were cross-linked between adjacent cellulose chains to some degree. These results agreed well with the ESCA data; the N1s/C1s ratios increased and O1s/C1s ratios decreased with the TAF addition. The water retention value (WRV) decreased because of the drop in swellability of the cross-linked fabric and the moisture regain value (MRV) decreased because the total water absorption sites diminished. In particular, the irradiated cellulose/PIA/TAF fabrics exhibited more distinct effects than the irradiated cellulose/PIB/TAF fabrics and the AM/PI/TAF fabrics were more photoactive in this UV-irradiation system than regular/PI/TAF fabrics.