Simulation of the Elastic Properties of Reinforced Kevlar-Graphene Composites

TL;DR

This paper models the elastic properties of Kevlar-graphene composites, showing that a graphene outer layer can significantly enhance transverse strength when chemically bonded to Kevlar yarns.

Contribution

It introduces a 2D linear elasticity model predicting optimal graphene layer thickness for strengthening Kevlar fibers.

Findings

Graphene layer radius of about 4% of Kevlar radius yields significant strengthening.

Chemical bonding between graphene and Kevlar enhances transverse strength.

Model suggests outer graphene layer improves fiber durability against transverse deformation.

Abstract

The compressive strength of unidirectional fiber composites in the form of Kevlar yarn with a thin outer layer of graphene was investigated and modeled. Such fiber structure may be fabricated by using a strong chemical bond between Kevlar yarn and graphene sheets. Chemical functionalization of graphene and Kevlar may achieved by modification of appropriate surface-bound functional (e.g., carboxylic acid) groups on their surfaces. In this report we studied elastic response to unidirectional in-plane applied load with load peaks along the diameter. The 2D linear elasticity model predicts that significant strengthening occurs when graphene outer layer radius is about 4 % of kevlar yarn radius. The polymer chains of Kevlar are linked into locally planar structure by hydrogen bonds across the chains, with transversal strength considerably weaker than longitudinal one. This suggests that introducing outer enveloping layer of graphene, linked to polymer chains by strong chemical bonds may significantly strengthen Kevlar fiber with respect to transversal deformations.