Temperature dependence of the thermal conductivity and thermal diffusivity of treated oil‐palm‐fiber‐reinforced phenolformaldehyde composites

Abstract

AbstractThe effective thermal conductivity (λe) and effective thermal diffusivity (χe) of oil‐palm‐fiber‐reinforced treated composites were measured simultaneously with the transient plane source technique from 50 to 110°C. The fibers of the composites were treated with sodium hydroxide alkali, silanol, and acetic acid. The experimental results for the different treated composites showed that there were variations in λe and χe over this temperature range. However, the maximum values of λe and χe were observed at 90°C, in the vicinity of the glass‐transition temperatures of these composites. An effort was also made to predict the temperature dependence of λe and χe through the development of an empirical model. The theoretically predicted values of λe and χe for these composites were in excellent agreement with the experimental results over the entire range of investigated temperatures. Sudden increases in λe and χe in the glass‐transition region of these composites were indicative of the fact that the crosslinking density decreased and was at a minimum at the temperature at which λe and χe showed their maxima. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 3458–3463, 2003