Abstract
In order to clarify the relation between the structure and properties of poly(vinyl alcohol) (PVA) gel, differential scanning calorimetry (DSC) and stress relaxation measurements were carried out. A small and broad endothermic peak which appeared at about 45°C was attributed to the disentanglement of molecular chains. A sharp endothermic peak which appeared in the temperature range from 70°C to 110°C was attributed to the gel melting or transition from gel to sol. The endothermic enthalpy determined from the area enclosed by the melting endothermic peak and the beseline showed a maximum at a DMSO concentration around 0.277 mf, which was almost independent of the concentration of PVA. The relaxation spectrum of PVA gels showed a maximum as a function of DMSO concentration at 0.277 mf DMSO. It was suggested that the number and structures of junction zones and the conformations of flexible chains connecting junction zones are optimized to give maxima of the elastic modulus and the endothermic enthalpy of melting.
Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
