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The influence of chemical cross-links between a single-walled fullerene nanotube and a polymer matrix on the matrix−nanotube shear strength has been studied using molecular dynamics simulations. A (10,10) nanotube embedded in either a crystalline or amorphous polyethylene matrix is used as a model for a nonbonded interface (in the absence of cross-links). The simulations predict that shear strengths and critical lengths required for load transfer can be enhanced and decreased, respectively, by over an order of magnitude with the formation of cross-links involving less than 1% of the nanotube carbon atoms. At this level of chemical functionalization, calculations also predict that there is a negligible change in tensile modulus for a (10,10) nanotube.

A summary of three simulations related to the issue of load transfer in carbon nanotube/polymer composites is given. Each simulation considers a (10,10) nanotube in a polyethylene matrix modeled with either a united-atom or fully-atomic polyethylene representation. The first simulation uses molecular dynamics to model a 100 nm nanotube in polyethylene in which the nanotube and matrix interact through weak non-bonded interactions. No permanent stress transfer is observed for this system. The second simulation estimates the shear yield strength for the nanotube in each of the model polyethylene matrices. The third simulation addresses a chemically functionalized nanotube in which there are cross-links between the nanotube and matrix. The results indicate that the cross-linked system has an enhanced shear yield strength of one to two orders of magnitude larger than the non-bonded composites.