Soluble polyimide as liquid crystal perpendicular alignment layer

Journal of Materials Science - Three polyimides (PIs) were prepared from a diamine containing biphenyl ester group as a side chain and a corresponding dianhydride chosen from...     

Synthesis and properties of novel photosensitive poly(arylene ether sulfone) containing chalcone moiety in the main chain

A new series of photosensitive poly(arylene ether sulfone)s containing chalcone moiety in the main chain were synthesized from 4,4′-dihydroxychalcone (4DHC), 4,4′-difluorodiphenylsulfone (DFDPS) and bisphenol A (BPA). This series of polymers were characterized by ¹H NMR, FT-IR, UV spectroscopy, thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). The polymers were stable up to 400 °C, which indicates that the polymers possess good thermal properties. The polymers were found to be soluble in polar solvents and chlorinated solvents. However, the polymers were insoluble in hydrocarbons and in hydroxyl group-containing solvents. After the irradiation of UV light, the thin polymer film was crosslinked to give an insoluble film in the absence of a photoinitiator or sensitizers. The rate of photocrosslinking was also examined and discussed.     

Preparation of photocrosslinkable polystyrene methylene cinnamate nanofibers via electrospinning

Nanoscaled photocrosslinkable polystyrene methylene cinnamate (PSMC) nanofibers were fabricated by electrospinning. The PSMC was prepared by the modification of polystyrene as a starting material via a two-step reaction process, chloromethylation and esterification. The chemical structure of PSMC was confirmed by 1H NMR and Fourier transform infrared spectroscopy (FT-IR). The photosensitivity of the PSMC was investigated using ultraviolet (UV) spectroscopic methods. Electrospun PSMC nanofiber mat showed excellent solubility in many organic solvents. UV irradiation of the electrospun mats led to photodimerization to resist dissolving in organic solvents. The morphology of the nanofiber was observed by scanning electron microscopy (SEM) and the result indicated that the average diameter of nanofibers is 350 nm and the crosslinked nanofibers were not collapsed after dipping into organic solvent showing good solvent-stability. This photocrosslinked nanofibers has the potential application in filtration, catalyst carrier and protective coating.     

Synthesis and characterization of a novel photocrosslinkable fluorinated poly(arylene ether) for optical waveguide

To improve its chemical resistance and mechanical stability, a novel fluorinated poly(arylene ether) bearing a photocrosslinkable chalcone group in the main chain was successfully synthesized by means of polycondensation between 4,4′-dihydroxychalcone and decafluorobiphenyl in N,N-dimethylacetamide in the presence of the excess anhydrous potassium carbonate. The structure of polymer was characterized by ¹H NMR and ¹⁹F NMR spectroscopies. The resulting polymer shows excellent solubility in common organic solvents, high glass transition temperature and good thermal stability. Crosslinking of the resulted polymer has been demonstrated by UV irradiation. Near-IR spectra of polymer film before and after UV irradiation show no absorption at the telecommunication wavelengths of 1310 and 1550 nm, demonstrating that the resulting polymer is good candidate material for optical waveguide application.