Functionalization of Poly(propylene) Fabric with 4‐Vinylpyridine, N,N‐Dimethylacrylamide and Styrene by γ‐Radiation‐Induced Grafting in an Aqueous Environment

Abstract

Summary: VP and co‐monomers DMAAm and ST were successfully grafted onto a PP fabric in an emulsion copolymerization process initiated by γ‐radiation. The radiation dose, concentration of VP, the ratio of VP/DMAAm and VP/ST in the reaction solution, and the reaction temperature dependent graft copolymerization were investigated. The order of dependence of the initial rate of grafting on the radiation dose was found to be in the range of 1.2 to 0.93 for VP; 0.84 to 0.70 for VP/DMAAm and for VP/ST was in the range of 0.59 to 0.41. The activation energy of the graft copolymer reaction was determined to be 40.18 J · mol−1 for 0.464 mol · L−1 VP. In the case of co‐monomer mixtures (VP/DMAAm: 0.464/0.5) the energy of activation was noticeably higher at 49.71 J · mol−1 while for VP/ST (0.464/0.436) the activation energy was same as that of VP. XRD results showed that overall crystallinity significantly decreased with the increase of graft weight with a noticeable change in the chemical structure of the PP, indicating that the graft copolymer reaction was taking place both in the amorphous and crystalline regions of PP. A similar characteristic behavior was also obtained by DSC, which revealed the presence of an endotherm process in the range of 25 to 130 °C depending on the degree of grafting, attributed to the grafted chains of the monomer/co‐monomers. In order to determine the graft copolymer reaction of VP, DMAAm and ST onto the backbone of PP, the reaction products were characterized by FTIR spectroscopy. A good correlation was found between changes of crystallinity and level of graft copolymerization as determined by WAXRD and DSC.Typical XRD traces of as‐received PP fabric (PPF) and grafted with VP (PPF‐g‐VP).magnified imageTypical XRD traces of as‐received PP fabric (PPF) and grafted with VP (PPF‐g‐VP).

Synthesis and cellular compatibility of multi-block biodegradable poly(ε-caprolactone)-based polyurethanes

“…Such discrepancies between these two techniques are not uncommon. 40,41 The difference can be explained considering that the X C XRD is measured as the ratio between crystalline PCL phase scattering and the whole X-ray scattering of the sample (amorphous and crystalline diffraction of both hard and so segments), whereas in the case of DSC analysis X C DSC is related to the crystallinity of the PCL phase only (see Experimental). Despite these differences, variations in the degree of crystallinity with structure follow similar trends.…”

The molecular surface conformation of surface-tethered polyelectrolytes on PDMS surfaces

“…The SFG spectrum collected from the PDMS surface grafted with DMAA exhibited a new peak at 2955 cm À1 , which was attributed to the C-H stretching vibration of the -CH 3 group in -N(CH 3 ) 2 of DMAA. 68 While for ZW and AA modified PDMS no obvious peak from the grafted moieties were observed.…”