A rotational isomeric state model with neighbor interactions is used to calculate mean-square unperturbed dimensions and dipole moments for vinyl chloride chains CHa-(CHCI-CH,,)zH having degrees of polymerization x ranging from 1 to 150 and stereochemical structures ranging from perfect syndiotacticity to perfect isotacticity. Conformational energies used in the calculation were those which had...

five new aromatic poly(amide-imide)s (5a-e) were synthesized by direct polycondensationreaction of n-(4-carboxy phenyl) trimellitimide (3) with five aromatic diamines (4a-e) by usingtriphenyl phosphite in n-methyl-2-pyrrolidone (nmp) and pyridine at solution containingdissolved cacl2. all of the polymers were obtained in quantitative yields with inherentviscosities between 0.29-0.40 dl/g. the r...

in this research, hydrogels based on poly vinyl alcohol and poly acrylic acid blend were prepared which were cross-linked by applied thermal conditions. afterward, effects of time and heating on water uptake were investigated. the highest water uptake value exhibited by the sample that was heated for 20 min. at 110 ºc was about 2129% after 4 days at equilibrium state. hydrogels exhibited ph-sen...

A novel chlorinated polyvinyl chloride (CPVC) membrane with low area resistance and excellent cycling performance was prepared for vanadium flow batteries (VFBs). Poly(vinyl pyrrolidone) (PVP), in which amine groups could be protonated the acidic conditions, introduced into CPVC to conduct ions. The positively charged can not only form successive smooth pathways ion transport, but also prevent ...