Increasing the thermal conductivity of typically insulating polymers, such as nylon 6,6, opens new markets. A thermally conductive resin can be used for heat sink applications. This research focused on performing compounding runs followed by injection molding and through‐plane thermal conductivity testing of carbon filled nylon 6,6 based resins. The three carbon fillers investigated included an electrically conductive carbon black, synthetic graphite particles, and a surface treated polyacrylonitrile (PAN) based carbon fiber. Conductive resins were produced and tested that contained varying amounts of these single carbon fillers. In addition, combinations of fillers were investigated by conducting a full 23 factorial design and a complete replicate. The objective of this paper was to determine the effects and interactions of each filler on the thermal conductivity of the resins. Synthetic graphite particles caused the largest increase in composite thermal conductivity. In addition, all the single fillers and combinations of fillers caused a statistically significant (at the 95% confidence level) increase in composite thermal conductivity. Polym. Compos. 25:186–193, 2004. © 2004 Society of Plastics Engineers.

Electrically and thermally conductive resins can be produced by adding conductive fillers to insulating polymers. Mechanical properties such as tensile modulus, ultimate tensile stress, strain at ultimate tensile stress, and notched Izod impact strength are also important and cannot be ignored. This study focused on performing compounding runs, followed by injection molding and evaluation of tensile and impact properties of carbon filled nylon-6,6 based resins. The three carbon fillers investigated include an electrically conductive carbon black, synthetic graphite particles, and a surface treated polyacrylonitrile (PAN) based carbon fiber. Resins containing varying amounts of these single carbon fillers were produced and tested. In addition, combinations of fillers were investigated by conducting a full 2 3 factorial design and a complete replicate. The addition of carbon fiber increased the composite tensile modulus, ultimate tensile stress, and impact strength. Also, in many cases, combining two or three different fillers caused a statistically significant effect at a 95% confidence level. When comparing the results of this study with prior work, it appears that increased heteroatoms present on the carbon fiber surface likely improve composite ultimate tensile stress and impact strength.

ABSTRACT:The electrical conductivity of resins can be increased by adding electrically conductive carbon fillers. A significant amount of work has been conducted varying the amount of single conductive fillers in a composite material. Limited work has been conducted concerning the effect of combinations of different conductive fillers. In this study, three different carbon fillers were used in nylon 6,6: carbon black, synthetic graphite particles, and a surface treated polyacrylonitrile (PAN) based carbon fiber. The goal of this project was to determine the effect of each filler and combinations of different fillers on the electrical conductivity of conductive resins. A 2 3 factorial design was analyzed to determine the effects of the three different carbon fillers in nylon 6,6. The results showed that carbon fiber caused the largest increase in composite electrical conductivity and that all the combinations of different fillers do have a statistically significant effect on composite electrical conductivity. C

Electrically conductive resins can be made by adding electrically conductive fillers to typically insulating polymers. Resins with an electrical resistivity of approximately 100 ohm‐cm or less can be used for electromagnetic and radio frequency interference shielding applications. This research focused on performing compounding runs followed by injection molding and shielding effectiveness testing of carbon filled nylon 6,6 based resins. The three carbon fillers investigated included an electrically conductive carbon black, synthetic graphite particles, and a surface‐treated polyacrylonitrile (PAN)‐based carbon fiber. Conductive resins were produced and tested that contained varying amounts of these single carbon fillers. In addition, combinations of fillers were investigated by conducting a full 23 factorial design and a complete replicate. The objective of this paper was to determine the effects and interactions of each filler on the shielding effectiveness properties of the conductive resins. Carbon fiber caused the largest increase in shielding effectiveness. Also, all the single fillers and combinations of fillers were statistically significant at the 95% confidence level, except the composite containing carbon black and synthetic graphite particles tested at 800 MHz. Polym. Compos. 25:407–416, 2004. © 2004 Society of Plastics Engineers.