A polydimethylsiloxane sample of an average molecular weight 450

000 was fractionated into eight fractions by the reprecipitation method. By determining their intrinsic viscosities and osmotic pressures in toluene solution

the [η]-M relation was established:[η] = 1.17×10-2 Mn 0.71 Toluene

25℃And the KJθ values of polydimethylsiloxane were calculated by means of the Flory-Fox-Schaefgen method.Kθ= 7.45×10-2 Toluene

25℃Kθ= 8.81×10-2 Toluene

50℃Kθ= 2.89×10-2 Cyclohexane

25℃These values show that the temper.