Synthesis of Poly (3-acetylpyrrolyl methine) with Azobenzene Side Groups and Study on Its Third-order Nonlinear Optical Property

A novel soluble π-conjugated polymer, poly [（3-acetylpyrrole-2, 5-diyl） p-（N, N-dimethylamino） azobenzylidene] （PAPDMAABE）, was synthesized by condensation of 3-acetylpyrrole with 4-aldehyde-4＇-dimethylaminoazobenzene （ADMAA）. The chemical structure of PAPDMAABE was characterized by Fourier transform infrared spectroscopy （FTIR）, ^1H-NMR, and UV-Vis-NIR spectra. Transmission electron microscope （TEM） analysis for PAPDMAABE indicates that part of PAPDMAABE is in crystal state, due to the short-range order of the polymer. Thermogravimetric analysis （TGA） curve shows that the polymer has good thermal stability and its decomposition temperature is 248℃. The optical band gap of PAPDMAABE obtained from the optical absorption spectrum is about 1.73 eV. The resonant third-order nonlinear optical property of PAPDMAABE at 532 nm was studied using degenerate four-wave mixing （DFWM） technique. The resonant third-order nonlinear optical susceptibility of the polymer is about 7.48×10^-8 esu.

Poly(N,N-dimethylaminoethyl methacrylate) Grafted Poly(vinyl chloride)s Synthesized via ATRP Process and Their Membranes for Dye Separation

To functionalize poly（vinyl chloride）（PVC） for various applications, monomers containing tertiary amine group are incorporated into PVC via atom transfer radical polymerization（ATRP） initiated by the labile chlorines in their backbones. The kinetics of synthesis was carefully investigated, and it is proven that the grafting polymerization process can be effectively controlled by regulating the reaction time. The membranes are fabricated using PVC and copolymers by non-solvent induced phase separation（NIPS） process. The hydrophilicity and pore structure of copolymer membranes were enhanced as well, these membranes are endowed with positive charge. When PDMA%（i.e., the PDMA weight percentage in copolymer） is 31.1%, the flux and Victoria blue B rejection are 26.0 L·m·^-2·h^-1（0.5 MPa） and 91.2%, respectively. Thus, the newly synthesized polymer is proven to be a promising material for dye separation with positive charges.

THERMOSENSITIVE SUPERABSORBENTS BASED ON POLY(N,N-DIETHYLACRYL AMIDE-co-SODIUM ACRYLATE)

A series of poly（N,N-diethylacrylamide-co-sodium acrylate） with a degree of crosslinking of 1 mol% have been prepared as therrnosensitive superabsorbents for water. The critical swelling temperatures or the volume phase transition temperature （VPTT） and the water absorption capacity of the polymers can be modulated by varying the amount of sodium acrylate （0-60 tool%） in the copolymers. The water absorption and swelling properties of the different hydrogels have been studied as function of temperature. The crosslinked copolymers can absorb large amounts of water at ambient temperatures and dehydrate at higher temperatures with relative ease, making the absorbent materials thermally responsive and thus reusable. The water absorption capacity of the copolymers depends on the pH of the media as the acrylate monomer has a higher water absorption in its deprotonated state. Added urea in the media raises and sharpens the VPTT values of the copolymers containing sodium acrylate.