Application of aramid pulp in EPDM internal insulator

Four methods of pretreatment of aramid pulp were applied to prepare the ethylene propylene diene monomer (EPDM) composites, and the effects of pulp pretreatment and pulp content on the mechanical and ablative properties of the composites were studied. In addition, the residues of the composites were analyzed by TGA. Experimental results indicate that the dispersion of non-pretreated aramid pulp is limited when the pulp content is greater than 6 phr in the EPDM matrix, as a result the properties of composites is impaired. The aramid pulp pretreated with silane coupling, however, can enhance both dispersion of the pulp in the EPDM matrix and stability and mass of residual char. The mass of residual char tested by TGA is increased to 33.9% from 30.4% (898.6°C), and the linear ablation rate of EPDM/aramid-pulp composites is declining by 31.6% compared with non-pretreated composites. Aramid pulp pretreated by inorganic powder, improved dispersion of pulp in the EPDM matrix, but the mechanical and ablative properties are not improved remarkably by reason of the poorly interfacial combined properties between inorganic powder and EPDM matrix.