Factors affecting radiation grafting of N-vinylpyrrolidone onto nylon-6 fabric

Abstract

<span style="font-size: 16.0pt;font-family:Fd1490491-Identity-H;mso-bidi-font-family:Fd1490491-Identity-H">The effect of monomer concentration, exposure time, dose rate fabric-to-liquor ratio and irradiation temperature on the kinetic parameters of grafting N-vinylpyrrolidone (NVP) onto nylon-6 fabric has been studied. Induction period is observed before the start of grafting process, especially at low dose rates and low NVP concentrations. Electron spin resonance study indicates that the oxygen still remaining in the grafting solution is possibly responsible for the existence of induction period via peroxide formation with free radicals. The order of the grafting process is found to decrease linearly with the increase in dose rate at 0.766 per increase in dose rate by 1 Gy/s. It decreases from a second order to a first order kinetics as the dose rate increases from <span style="font-size:16.0pt;font-family:Fd1413727-Identity-H;mso-bidi-font-family: Fd1413727-Identity-H">0.37 <span style="font-size:16.0pt;font-family: Fd1490491-Identity-H;mso-bidi-font-family:Fd1490491-Identity-H">Gy/s to 1.81 Gy/s. The grafting rate constant increases with the increase in dose rate to the power of 2.9. The increase in fabric-to-liquor ratio from 1:7.5 to 1:1 5 increases the reaction order and decreases the grafting rate constant. The increase in the grafting temperature decreases the grafting rate and rate constant. The calculated activation energy 23.6 kJ/mole is attributed to the homopolymerization of NVP and the existence of unidentified transfer process.

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