Polyoxymethylene/carbon nanotubes composites prepared by solid state mechanochemical approach

Polyoxymethylene (POM)/carbon nanotubes (CNTs) (2: 1 by weight) composite powders were prepared by a solid rnechanochemical method with a self-designed pan type mill equipment. Photos of SEM and TEM show that the average size of composite powder is several micrometres, and the CNTs adhered to the surface of POM powder to form a special structure like silk cocoons. The composites were prepared by adding the mixed POM/CNTs powder to POM matrix. Three different processing methods were tried and the results confirm that the solid mechanochemical method is the most effective to reinforce the POM matrix. The good dispersion of CNTs in POM matrix is attained and the interface interaction between CNTs and POM is improved through the mechanochemical mixing. Compared with talc, calcium carbonate and carbon black, CNT is the most effective filler to reinforce POM due to its high aspect ratio. Differential scanning calorimeter analysis shows that in the presence of CNTs, the crystallisation temperature and enthalpy of POM are enhanced. Thermogravimetric analysis data suggest that the thermal stability of POM is also improved.