Relaxation phenomena in polyvinyl alcohol

Abstract

Dissipative effects are investigated by means of relaxation spectrometry in films of polyvinyl alcohol with various molecular weight and hydration degree. Peaks of mechanical loss reveal two relaxation transitions (α- and β-peaks) and one first order phase transition (δ-peak). It is found that decrease of hydration degree and increase of crystallinity degree in polyvinyl alcohol essentially increases temperature of α-transition. The α-peak shifts to the higher temperatures area with growth of the molecular weight. Situation of the β-peak does not depend on molecular weight but changes depending on hydration degree. Change of oscillation frequency is noted in area of α- and β-transition, which is indicative of shear modulus defect.

Keywords

• transitions α, β, δ
• polyvinyl alcohol, relaxation, relaxation spectrometry, vitrification