Kinetic studies of radiation induced grafting of N-vinylformamide onto polyethylene/polypropylene fibrous sheets and testing its hydrolysed copolymer for CO2 adsorption

Kinetics of the grafting process is highly important for understanding reaction mechanism pertaining graft copolymer preparation quality, reproducibility and economics. In this study, the kinetic behaviour of grafting of N-vinylformamide (NVF) monomer onto polyethylene coated polypropylene (PE/PP) fibrous sheet was investigated with respect to the dependence of degree of grafting (G%) on various reaction parameters like monomer concentration, absorbed dose, and reaction temperature for the first time. The kinetic analysis covered not only the initial polymerisation rate (rp0), radical recombination rate and delay time (t0) but also orders evaluations of the grafting rate dependence on the monomer concentration, absorbed dose and temperature. The chemical and morphological changes caused by the inclusion of poly(NVF) grafts into PE/PP substrates were monitored by Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM). The results of the present study led to the establishment of a quantitative kinetic description for grafting of NVF onto PE/PP and demonstrated that the degree of grafting is strongly dependent on the investigated reaction parameters. The adsorbent containing poly(vinylamine) obtained by the hydrolysis of the grafted poly(NVF) chains showed a remarkable CO2 adsorption capacity of 1.36 mmol/g at room temperature and a pressures of 30 bar.