Abstract The Nylon and liquid crystal polymer(LCP) filled with conductive carbon fiber applied to 155Mbps and 1.25Gbps transceiver modules for electromagnetic(EM) shielding were studied. The measured results showed that the shielding effectiveness(SE) of 155Mbps and 1.25Gbps transceiver module were 13dB and 20dB to conform to FCC class B standard, respectively. This indicates that the plastic housing filled with conductive carbon fiber is suitable for EM shielding in plastic laser transceiver module applications.

Abstract Electromagnetic shielding of nylon-66 composites applied to laser modules was studied experimentally and theoretically. The effects of conductive carbon fiber length and weight percentage upon the shielding effectiveness (SE) of nylon composites were investigated. The result showed that the SE of long carbon fiber filled nylon-66 composites was found to be higher SE than short carbon fiber filled nylon-66 composites under the same weight percentage of carbon fibers. In addition, higher electromagnetic shielding was obtained for the composite with higher contents of carbon fibers at the same length. The SE of conductive carbon fiber filled nylon-66 composites was measured to be 41 dB at low frequency of 30 MHz and 59 dB at high frequency of 1.5 GHz. The results of SE predicted by the proposed theoretical model and the results measured by experiments were in good agreement with each other for carbon fibers filled nylon-66 composites of different lengths. The effects of fiber orientation on SE of nylon and LCP composites were also investigated. The result showed that the SE of LCP composites was found to be higher than nylon composites under the same weight percentage of carbon fiber. This is due to that the fiber orientation in LCP composites attempts to keep the same direction.

A new method for pre-impregnating nickel coated carbon fiber with a thermoplastic polymer to make towpreg, similar to a recently developed coating-line by João P. Nunes et al and a new electrically conductive thermoplastic are developed. A melted bath was used to help mitigate health concerns and waste for dispersion of nickel coated carbon fibers (NCF) in low density polyethylene (LDPE). This towpreg was then mixed with more LDPE or a mixture of LDPE and nickel nanostrands (NiNS) to a desired filler volume fraction to test the electrical conductivity of the composite. Some of these mixtures were then injection molded and tested again for conductivity as well as tensile and impact strength and compared to each other and the non-injection molded samples. It was found that mixing NiNS into the polymer in addition to NCF created a more conductive part than with NCF alone, in a couple orders of magnitude. Also, the shorter the NCF were, the greater the contribution of the NiNS to the electrical properties of the NCF filled material. The tensile strength was increased by adding the NCF and NiNS, while the impact strength (toughness) decreased.