Non-linear viscoelasticity of vapor grown carbon nanofiber/polystyrene composites

作者：Zhao, Li; Yang, Hongmei; Song, Yihu; Zhou, Yujie; Hu, Guo-Hua; Zheng, Qiang^*

来源：Journal of Materials Science, 2011, 46(8): 2495-2502.

DOI：10.1007/s10853-010-5098-8

• ELECTRICAL-CONDUCTIVITY
• POLYMER NANOCOMPOSITES
• THERMAL-CONDUCTIVITY
• RHEOLOGICAL BEHAVIOR
• PERCOLATION NETWORKS
• ELASTIC PROPERTIES
• REINFORCEMENT
• RUBBER
• MECHANISM
• NANOTUBE

The strain (gamma) dependences of viscoelasticity and electrical resistance (R) of vapor grown carbon nanofiber (VGCF)/polystyrene (PS) composites have been studied using simultaneous measurement technique. The composites containing at least 4 vol.% VGCF present two regions of strain softening at gamma < 10% and gamma > 30%, respectively. Using strain amplification factor introduced by hydrodynamic effects as vertical and horizontal shifting factors, the curves of dynamic storage modulus (G') and loss modulus (GaEuro(3)) as a function of gamma for the composites can be superposed, respectively, on those for the pure matrix at gamma a parts per thousand yen 30%. Significant deflection from the master curves can be observed at gamma < 30%. R tested as a function of gamma provides direct evidences for breakdown of filler-filler interactions even by a small strain perturbation. It is suggested that breakdown of filler-filler interactions plays a vital role in strain softening at small strains, whereas the matrix provides the main contribution to strain softening at large strains. Dynamic moduli G'(f,(0.1%phi)) and G ''(f,(0.1%phi)) of the filler phase at volume fraction phi at 0.1% strain are used to account for the viscoelastic contribution of the initial filler structure. Ratios of dynamic moduli of the filler phase to the composite at 0.1% strain, G'(f,0.1%)/G'(c,0.1%) and G ''(f,0.1%)/G ''(c,0.1%), exhibit percolation-like transition as a function of phi, which is in consistence with the electric percolation transition.

• 出版日期2011-4
• 单位浙江大学