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摘要
Influence of processing conditions on frequency (omega)-dependent dynamic rheology of vapor grown carbon nanofiber (VGCF) filled polystyrene (PS) melt (200 degrees C) with different VGCF volume fractions (phi = 0 similar to 0.05) was studied in the framework of a modified two phase model. In comparison with the composites processed in a strong-shear mixing condition (190 degrees C; 120 r/min-10 min), VGCF formed aggregates to a higher degree in those processed in a weak-shear mixing condition (190 degrees C; 30 r/min-5 mm). The filler aggregation was characterized by a higher value of strain amplification factor A(f)(phi) and a smaller relaxation exponent n related to the "filler phase". Furthermore, strain (gamma)-dependent amplification factor, A(f)(phi, gamma), and characteristic elastic and viscous moduli, G(f)'(phi, gamma(c)) and G(f)('')(phi, gamma(c)), were introduced to the two phase model for discussing the nonlinear rheology with increasing gamma. The results showed that the two phase model allowed discussing dynamic rheology of filled melts qualitatively. The processing condition influenced the dispersion of VGCF in the matrix while it did not influence relationships of elastic contribution R-f'(phi) against n for omega-dependent rheology as well as elastic modulus G(f)'(phi, gamma(c)) against nonlinear strain exponent x and viscous modulus G(f)('
- 出版日期2012-12-20
- 单位浙江大学
