PAN chemical modification. Synthesis and characterization of terpolymers with 1,2,4-oxadiazolic pendant groups

ISABEL VEGA; WALTER MORRIS; NORMA D'ACCORSO

REACTIVE & FUNCTIONAL POLYMERS

Elsevier

Lugar: Netherlands; Año: 2006 vol. 66 p. 1609 - 1618

1381-5148

Abstract The terpolymers containing oxadiazole pendant groups, obtained from chemical modification of a commercial polymer, present great interest due to their novelty and possible interesting properties. The synthesis of amidoxime-nitrile-3-hydroxyphenyl-1,2,4-oxadiazole (ANHOT) with different conversion time were prepared by chemical modification of commercial polyacrylonitrile (PAN) as starting material. The first step of ANHOT synthesis was the well-known nitrile conversion into amidoxime groups. Afterwards, the 3,5-disubstituted 1,2,4-oxadiazolic ring was obtained by treatment of amidoxime -groups with an acyl chloride. The molecular structures were confirmed by IR, UV-Vis, 13C and 1H NMR spectroscopies. Conversion yields were calculated from elemental analysis. Thermal properties were studied by DSC and TGA techniques. All ANHOT series are completely soluble in very polar solvents. The dependency of viscosity with the conversion degree was analyzed with a control rate (CR) viscosimeter. Viscoelastic behavior was analyzed by rheometric measurements. The highest viscosity and elastic behavior are obtained with ANHOT of an hour conversion time, in this way it is the most attractive polymer among the ANHOT series. Keyword: Amidoxime-nitrile-3-hydroxyphenyl-1,2,4-oxadiazole terpolymer; Polyacrylonitrile; High viscosity.