Rheology of blends of a thermotropic liquid crystalline polymer with polyphenylene sulfide

Blends of thermotropic liquid crystalline polymer (LCP) and polyphenylene s ulfide(PPS) were studied over the entire composition range using Rheometric s Stress Rheometer, capillary rheometer, and differential scanning calorime ter. There is no molecular scale mixing or chemical reaction between the co mponents, as evidenced by melting and crystallization points, in the PPS ph ase. From the strain scaling transients test at low-rate, LOP and the blend s require approximately 60 strain units to obtain steady state shearing res ults. The large recoveries in the strain recovery test, magnitude 3 to 3.3, strain unit, are likely the results of texture present in LCPs. With incre asing PPS content in LCP/PPS blends, the total recovery declines. Scaling o f the transient strain rate remains, but the magnitude of the transients is reduced. At low-rate, when the LCP is added, to the PPS, the pure melts ha ve similar viscosity: 500 Pa . s for LCP and 600 Pa . s for PPS, but the vi scosity of the blends goes through a maximum with concentration that is nea rly three times the viscosity of the individual melts. At high-rate, a sign ificant depression of the viscosity is observed in the PPS-rich composition s and this may he due to the fibrous, structure of the LOP at high shear ra tes.