Silarylene-containing oligo(ether-amide)s based on bis(4-(4-amino phenoxy)phenyl)dimethylsilane. Effect of the dicarboxylic acid structure on some properties

Inherent viscosity and MALDI-TOF analyses suggest the formation of oligomeric chains with sequences A–B, (A–B)2 and (A–B)3. The properties and therefore the eventual applications of these materials are modulated by the flexibility and the aromatic content of the chains.

Synthesis, Characterization, and In Vitro Antimicrobial and Anticancer Evaluation of Copolyester Bearing 4-Arylidene Curcumin in the Main Chain

Synthesis of random copolyester bearing 4-arylidene curcumin M1 in the polymer backbone was prepared by solution polycondensation method. The influence of copolyester bearing 4-arylidene curcumin M1 unit on the properties of copolyester such as inherent viscosity, solubility, and thermal stability was investigated and studied in detail. The inherent viscosity and polydispersity index of the copolyester were found to be 0.19 dL/g and 1.38, respectively. The chemical structure of the copolyester was investigated by Fourier-transform infrared spectroscopy (FTIR) and proton nuclear magnetic resonance (1H-NMR) spectroscopy. The physical properties of copolyester were characterized by thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), gel permeation chromatography (GPC), and X-ray diffraction (XRD) technique. Agar disc diffusion method was employed to study the antimicrobial activity of the random copolyester. In vitro anticancer activity against lung cancer (Hep-2) cell line was investigated.

Facile Synthesis, Characterization, and In Vitro Antimicrobial and Anticancer Activities of Biscoumarin Copolyester Bearing Pendant 3-(Trifluoromethyl)Styrene

Synthesis of random biscoumarin copolyester bearing pendant 3-(trifluoromethyl)styrene was prepared by the reaction of biscoumarin monomer 3 and hydroquinone 5 with azeloyl chloride. The influence of pendant 3-(trifluoromethyl)styrene unit on the properties of copolyester such as inherent viscosity, solubility, and thermal stability was investigated and compared in detail. The inherent viscosity and polydispersity index of the copolyester were found to be 0.15 dL/g and 1.36, respectively. The chemical structure of the copolyester was investigated by Fourier-transform infrared spectroscopy (FTIR) and proton nuclear magnetic resonance (1H-NMR) spectroscopy. The physical properties of copolyester were characterized by thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), gel permeation chromatography (GPC), and X-ray diffraction (XRD) technique. Agar disc diffusion method was employed to study the antimicrobial activity of the random copolyester. In vitro anticancer activity against lung cancer (Hep-2) cell line was also investigated.

A Novel Synthesis Process of PPTA by Nitrogen Cooling for Reaction Heat Removal

Poly (p-phenylene terephthalamide) (PPTA) was synthesized by different processes including single feeding, batch feeding and inlet nitrogen cooling. The effects of these three processes on reaction heat removal of PPTA polymerization were compared. The degree of reaction heat removal was characterized through the changes of system temperature and stirring rate with reaction time. Results suggested that during the processes of batch feeding and nitrogen cooling, system temperature could be effectively decreased and PPTA yields were both larger than 98 %. It indicated that the exothemic heat could be transferred faster and better and monomers could completely react. The inlet incorporation of nitrogen cooling led to the maximum of inherent viscosity (ηinh) of resulted PPTA. This result indicated that nitrogen cooling could effectively transfer the reaction heat and prolong the gel precipitation time of PPTA.

Fabrication and Fluorescence Characterization of the Polyimides with Different Molecular Weights

In this paper, a series of polyimide (PI) films with different monomer mole ratios between PMDA and ODA (0.980: 1, 0.990: 1, 1.000: 1, 1.010: 1 and 1.015: 1) were prepared in order to investigate the effect of molecular weight on optical properties. Inherent viscosity values were taken as a measure of the molecular weight. The fluorescence properties of the PI films have been measured. The fluorescence spectra show that three obvious emission peaks can be observed at 583 nm (1.00 dL/g), 594 nm (1.42 dL/g) and 603 nm (1.57 dL/g) respectively. In addition, emission peaks show red-shift with the increase of molecular weight, which can attribute to the decease of orbital energy caused by conjugated effect.

Preparation of aliphatic polypyromellitimide particles by polycondensation of nylon-salt-type monomers derived from aliphatic diamines with diethyl pyromellitate in ethylene glycol

Polycondensations of nylon-salt-type monomers composed with diethyl pyromellitate and aliphatic diamines with various methylene lengths were performed at 130 °C in ethylene glycol to afford flower-like particles. Before the polycondensation, the salt monomer solution was homogenous. As the polycondensation proceeded, the solution became turbid and polyimide particles grew to around 15 µm in 8 h. Further polycondensation broke the particles into small pieces. The polyimide particles showed the distinctive odd-even effect of the methylene chain of diamine in both inherent viscosity and crystallinity. The polyimide particles using diamine with even-methylene length had higher crystallinity and lower inherent viscosity than those using diamine with odd-methylene length.

N-Alkyl PPTA: Preparation and Characterization

N-alkyl poly(p-phenylene terephthalamide)s (PPTA) is synthesized from PPTA and bromoalkane via metalation process in a solution of potassium methylsulfinylcarbanion in dimethyl sulfoxide. The modified PPTAs have been dissolved in conventional solvents, such as THF and CHCl3. The effects of substituted alkyl, substitution degree and inherent viscosity of PPTA on the solubility of N-alkyl PPTA were discussed. The substitution degree is calculated by FTIR and NMR. The molecular weight and distribution of N-alkyl PPTA has been obtained by GPC. The thermal properties are also discussed.