The exceptional mechanical and thermal properties of vapor grown carbon nanofibers (VGCFs) and single-walled carbon nanotubes (SWNTs) have led to their extensive use as reinforcing agents in fabricating nanocomposites. However, difficulties in achieving good nanomaterial dispersion and interface interaction between the nanomaterial and polymer matrix have hindered the performance of the final nanocomposites. This has led to considerable research being focused on alternate routes of nanomaterial incorporation. Resin infiltration of the nanomaterial bucky paper is one such method. It involves layers of highly entangled sheets of nanomaterial, made by filtering nanomaterial dispersion in a solvent, infiltrated with resin usually assisted by vacuum. Many factors affect the properties of resin infiltrated nanomaterial bucky paper; most important of which are the pore size and rope size of the bucky paper that are largely dependent on mixing time and concentration nanomaterial dispersion.

A two level factorial design with mixing time of 2 and 4 days, concentration of 0.75 and 1.5 mg/ml, and thickness of 200 and 400 μm was employed to study effect of VGCF bucky paper pore size, rope size and thickness on the mechanical properties of unsaturated polyester resin infiltrated nanocomposite. Pore size of the bucky papers was measured on an autosorb pore size analyzer from Quantachrome while rope sizes were measured from microscopic images. The results of the study indicate that pore sizes and rope sizes indeed have a large effect on the properties of the final nanocomposite. Bucky papers should ideally have small rope sizes in order to allow for effective load transfers. On the other hand, small rope sizes result in small pore sizes which make resin infiltration difficult leading to the nanocomposite failure. This study helps in determining conditions to make ideal VGCF bucky papers that have pore sizes large enough to allow resin infiltration but also rope sizes small enough to allow good load transfer.