Conformational Transition of Styrene–p-Chlorostyrene Triblock Copolymers in Selective Solvents

Effect of inorganic salts on viscosity of acrylonitrile‐N‐vinylpyrrolidone copolymer solutions

“…Changes of solution viscosity become less obvious with addition of ZnCl 2 . When temperature increases from 25 to 45°C, the viscosity of the copolymer solution containing NaCl drops most considerably and the copolymer solution consisting of FeCl 3 shows the slowest decrease.…”

“…It is feasible to decrease the dope viscosity by increasing the comonomer concentration, but percentage conversion of AN in the polymerization reaction always decreases with the increase in the comonomer content. 1 The effects of inorganic salts on viscosity of AN copolymer solutions have been observed and reported in the literature, 2,3 and addition of LiCl may decrease the viscosity of AN copolymer solutions. 4 To our knowledge, there are only a few reports on effects of inorganic salt ions, that is, Na , on AN copolymer solutions, but there is no report on Nvinylpyrrolidone(N-VP) as comonomer.…”

“…Transition-metal salts FeCl 3 and CuCl 2 are difficult to dissolve in DMSO solvent. Saturated solutions consisting of FeCl 3 and CuCl 2 were firstly obtained.…”

“…As the transition-metal salt concentration was increased from 0 to 0.035 mol/L, the viscosity of copolymer solutions showed an prominent increase, except for the fact that the increase in viscosity of copolymer solution containing ZnCl 2 was less obvious, which shows disagreement with the values reported. 9 It is chemical interaction that induces the viscosity of copolymer solutions consisting of FeCl 3 and CuCl 2 to increase with the increase of concentration of transition-metal salts. The presence of transition-metal ions, particularly those of iron or copper in AN copolymer solutions, is considered as an important factor for yellowing of acrylic fibers.…”

Stability of acrylonitrile–acrylamide copolymer solutions

“…In fiber technology, acrylonitrile (AN) polymer solutions that rapidly cool to the processing temperature tend gradually to the equilibrium state, which is accompanied by variations of the viscosity properties. Concentrated polar AN polymer solutions exhibit intense molecular interactions, and some examples illustrating the aging phenomena of acrylic polymers have been observed and reported in the literature;2, 3 the addition of additives may vary the viscosity of AN polymer solutions 4, 5. To our knowledge, there are only a few reports on dilute AN copolymer solutions, but there are almost no reports on concentrated AN copolymer solutions with acrylamide (AAM) as a comonomer.…”