Dynamic mechanical and thermal analysis of aligned vapor grown carbon nanofibers reinforced polyethylene.

摘要

Dynamic-mechanical and thermal characterization of aligned vapor grown carbon-nanofibers (VGCNFs)-reinforced high-density polyethylene (HDPE) has been performed. VGCNFs with diameters ranging from 50--200nm were used. Nanofibers were purified to remove amorphous carbon and metal catalyst, resulting in deagglomeration, and creating an open network that allowed polymer infiltration during mixing. High-shear mixing was used to disperse and distribute the nanofibers uniformly within the matrix. Extensional flow at different draw ratios (lambda) was used to obtain anisotropic nanoreinforced composite (NC) tapes. Dynamic Mechanical Analysis (DMA) showed a dual increase, in storage and loss modulus, with draw ratio. This behavior is attributed to the material recrystallization, which restricts chain mobility. Alignment of nanofibers favored the energy dissipation mechanism where chain-type structures are formed from the nanofiber/matrix interaction. Energy dissipation due to friction between particles or particle-matrix interactions was reflected in tans. Additionally, an increase in thermal stability was observed.