Influences of poly (vinyl alcohol) molecular weight and carbon nanotubes on radiation crosslinking shape memory polymers

Polyvinyl alcohol(PVA) of two molecular weights was used to prepare shape memory polymers based on chemical-crosslinking by glutaraldehyde.The chemical-crosslinking was done in the presence of 2-carboxyethvl acrylate oligomers(CEA) and nano-fillermulti-wall carbon nanotubes(MWCNT) and functionalized carbon nanotubes(MWCNT-NH_2)]followed by radiation-induced crosslinking.The analysis of the material revealed an increase in the gel fraction and a significant reduction in swelling of the nanocomposite material that was crosslinked with both glutaraldehyde and ionizing radiation.The radiation crosslinked nanocomposites demonstrated approximately a 90%gelation over a range of 50-300 kGy irradiation doses.The scanning electron microscopy(SEM) analysis showed a homogeneous distribution of nanocomposites in the composite matrix.The thermal properties of radiation crosslinked(PVA/CEA) and(PVA-CEA)-nano-fillers were investigated by a thermogravimetric analysis(TGA).The mechanical properties were examined via dynamic mechanical analysis(DMA) which showed significant variation because of the addition of nanocomposites.This radiation crosslinked materials show good shape memory behavior that may be useful in many applications based on the range of temperatures at which Tan 8 appears.