Modification of Sisal Fiber by In Situ Coating Steam Explosion and Electromagnetic Interference Shielding Effectiveness of Sisal Fiber/PP Composites

The technology of steam explosion was adopted to modify sisal fiber (SF) material and two different carbon particles, expanded graphite and conductive carbon black (CCB), were in situ coated on the surface of SF during steam explosion process. The DC conductivity and electromagnetic interference shielding effectiveness (SE) of the modified SF/polypropylene (PP) composites were studied and the measurement of electromagnetic interference (EMI) SE was conducted in two frequency ranges of 400-1,000 MHz and 1-18 GHz. The experimental results showed that this novel coating technology could improve the SE of the modified SF/PP composites significantly, which has a strong dependence on the loadings of the expanded graphite modified sisal fiber (SF-EG) and conductive carbon black modified sisal fiber (SF-CCB). When the loadings of SF-EG and SF-CCB reached 50 wt%, the maximum values of the SE were 33 dB and 51 dB, respectively. For the modified SF/PP composites, the experimental EMI SE values are in good correlation with the theoretical calculation values in far field of electromagnetic radiation. POLYM. COMPOS., 35:1038-1043, 2014. (c) 2013 Society of Plastics Engineers