Modification of acrylonitrile/acrylic acid copolymer films and fibers by dendrigraft formation

Samples of film, wet-and electro-spun fibers and powder were prepared from acrylonitrile/acrylic acid copolymer, with their specific surface areas being considerably different We attempted to alter the properties of the samples by increasing the amount of carboxylic acid groups on the surfaces through the formation of dendrite structures Dendrite molecules were grown by a reaction between the carboxylic acid groups of acrylic acid, activated by dicyclohexylcarbodiimide, and hydroxyl groups of citric acid Products were analyzed using Fourier transform infrared and NMR spectroscopy, optical microscopy, scanning electron microscopy and density measurements It was found that with an increase of the specific surface area, the percentage conversion increased indicating that the topochemical reactions were prominent The density of electro-spun fibers was the greatest indicating the most compact structure With an increase of step numbers of dendrigraft formation the density reached a minimum which points to the formation of nanoscale voids in the deposited dendrite structure (C) 2010 Society of Chemical Industry