Radiation grafting of acrylic acid onto poly (ethylene terephthalate) (PET) knittings was investigated by preirradiation technique. The influence of the grafting conditions, such as reaction time, ferrous sulfate concentration, preirradiation dose, organic additives, monomer concentration, and reaction temperature on the degree of grafting was investigated. Precise control over the degree of grafting was achieved by proper selection of the reaction conditions. The organic solvents such as methanol, acetone, isopropanol, THF, and MEK when used as sole medium do not allow the grafting to proceed, probably due to the inhibitory action.However, reasonable grafting proceeded when a mixture of water and organic solvent was used. Attenuated total reflectance-FTIR spectroscopy analysis of the grafted knittings confirmed the existence of carboxylic acid groups in the knittings. The surface morphology, as studied by scanning electron microscopy (SEM), was significantly influenced by the addition of organic solvents in the reaction medium.

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The preirradiation grafting of acrylic acid (AA) onto poly(ethylene terephthalate) (PET) had been found to affect the thermal and physical characteristics of fabric. The grafted fabrics with various graft levels were characterized by thermal gravimetric analysis (TGA), ATR-FTIR spectroscopy, contact angle, differential scanning calorimetry (DSC), X-ray diffraction (XRD), atomic force microscopy (AFM), and scanning electron microscopy (SEM). The initial decomposition temperature and T 50 were increased with the increase in degree of grafting. The percentage crystallinity was decreased as the degree of grafting increases. The detailed elemental analysis was done by X-ray photoelectron spectroscopy (XPS). The atomic ratio (O 1s /C 1s ) was found to increase significantly with increasing the degree of grafting and reached 0.64 at 14.5% grafting from 0.38 for virgin PET. The surface topography and morphology was strongly influenced as the degree of grafting was increased.

Radiation grafting of acrylic acid (AA)/Nvinyl pyrrolidone (NVP) binary mixture onto poly(ethylene terephthalate) (PET) knittings was investigated by preirradiation technique. The influence of the grafting conditions, such as monomer composition, reaction temperature, and the effect of storage time with temperature after irradiation on the degree of grafting was determined. ATR-FTIR spectroscopy analysis of the grafted knittings confirmed the existence of amide group of NVP in the knittings. The concentration of peroxides and effect of storage time on peroxide concentration were also determined by 2,2-Diphenyl-1-picrylhydrazyl at different temperatures. There was an increase in surface roughness of grafted PET in comparison to virgin PET as determined by atomic force microscopy and scanning electron microscopy. The grafted knittings were subsequently immobilized with collagen Type I which was further apt for the study of growth and morphology of human mesenchymal stem cell (hMSC). The immobilization of collagen on PET knittings has provided an excellent surface for the growth of hMSCs.

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