Development of sustainable polyoxymethylene-based composites with recycled carbon fibre: mechanical enhancement, morphology, and crystallization kinetics

Recycled carbon fibre was employed as a reinforcing material to prepare polyoxymethylene–based composites through a simple melting extrusion. An effective approach was developed to clean and modify the surface of as-received recycled carbon fibre with nitric acid and then with a silane-coupling agent. The mechanical evaluation demonstrated that a significant reinforcement was achieved for polyoxymethylene/recycled carbon fibre composites due to the improved interfacial adhesion between fibres and the matrix. The thermal stabilities of the composites were also improved in the presence of recycled carbon fibre. The morphological observation of impact fracture surfaces indicated a good interfacial boding between fibres and matrix. The studies on nonisothermal and isothermal crystallization behaviors showed that recycled carbon fibre acted as a nucleation agent for the crystallization of polyoxymethylene domain in composites; therefore, the crystallization rate and nucleation density increased remarkably due to the heterogeneous nucleating effect of recycled carbon fibre. These crystallization features may be advantageous for the enhancement of mechanical performance and processability of polyoxymethylene−based composites. Derived from a combination of polyoxymethylene and recycled carbon fibre, this study may provide a development guide for sustainable engineering materials with a great potential as well as a low cost for industrial and civil applications.