Cleavage of the Graft Bonds in PVDF–g–St Films by Boiling Xylene Extraction and the Determination of the Molecular Weight of the Graft Chains

To determine the molecular weight of graft chains in grafted films, the polystyrene graft chains of PVDF–g–St films synthesized by a pre-irradiation graft method are cleaved and separated by boiling xylene extraction. The analysis of the extracted material and the residual films by FTIR, nuclear magnetic resonance (NMR), and gel permeation chromatography (GPC) analyses indicates that most graft chains are removed from the PVDF–g–St films within 72 h of extraction time. Furthermore, the molecular weight of the residual films decreases quickly within 8 h of extraction and then remains virtually unchanged up to 72 h after extraction time. The degradation is due to the cleavage of graft bonds, which is mainly driven by the thermal degradation and the swelling of graft chains in solution. This allows determination of the molecular weight of graft chains by GPC analysis of the extracted material. The results indicate that the PVDF–g–St prepared in this study has the structure where one or two graft chains hang from each PVDF backbone.

Facile synthesis and properties of a cation exchange membrane with bifunctional groups prepared by pre-irradiation graft copolymerization

Low-cost and anti-degradation ion-exchange membrane named ETFE-g-poly(AA-co-SSS) with bifunctional groups prepared by the pre-irradiation grafting method.

Surface Modification of γ - Al2O3 nanoparticles by Electron Co-irradiation-induced Graft polymerization of MMA

ABSTRACTElectron beam co-irradiation graft polymerization has been carried out up to an absorbed dose of 30 kGy in air at room temperature between methyl methacrylate (MMA) monomer and γ- Al2O3 nanoparticles and micronparticles, respectively. The results showed that the percent graft of nano-Al2O3 and micron-Al2O3 is 6.4% and 0.9%, respectively. In the FT-IR spectra of irradiated nanoparticles, there was a new absorption peak at 1725 cm-1 that was attributed to carbonyl stretching vibration and Al-O-C bonds forming on the surface of nanoparitcle. But in the spectra of micron-Al2O3, the absorption peak at 1725 cm-1 was very weak. X-ray photoelectron spectroscopy (XPS) measurements confirmed the existence of carbonyl. The UV absorption intensities of two γ- Al2O3 powders strengthened after irradiation graft polymerization. These results showed that MMA has been successfully grafted onto nano-Al2O3 surface at the dose of 30 kGy. However, there were few new chemical bonds on micron-Al2O3 surface. It could be deduced that irradiation graft polymerization of γ- Al2O3 nanoparticles was easier than that of micronparticles.