Effects of pretreated polysulfonamide pulp on the ablation behavior of EPDM composites

Excellent ablative properties of ethylene–propylene–diene elastomer (EPDM) composites were obtained by adding pretreated polysulfonamide pulp (PSA-pulp). The effects of pulp pretreatment and pulp content on the mechanical and ablative properties of PSA-pulp/EPDM composites were studied. Experimental results showed that the tensile strength decreased slightly and the ablative properties increased by 3 folds on addition of 10 phr pretreated PSA-pulp. This significant improvement in the ablative properties was attributed to the enhanced dispersion degree and improved interfacial adhesion of pretreated PSA-pulp to EPDM matrix, which were observed from scanning electron microscopy. The ablation behavior of pretreated PSA-pulp/EPDM composites was proposed in accordance with the characterizations of thermogravimetric analysis (TGA), energy disperse X-ray spectroscopy (EDS) and pyrolysis-gas chromatograph–mass spectrometry (Py-GC–MS). The carbonized PSA-pulp acted as a skeleton in retaining the char layer and reduced the material loss during the high temperature ablation.