The temperature dependence of the coefficients of thermal expansion of phenolic resin

Cross-linked polymers, such as phenolic resin and its composites are widely used in industrial practice, but the absence of clear understanding on their thermal expansion behaviors in glassy state limits their applications, especially in the occasions where dimensional accuracy are addressed. The coefficients of thermal expansion (CTEs) of cured phenolic resin and inorganic particles filled phenolic resin at glassy state at different temperatures are analyzed in this article. The results show that the CTEs of glassy cross-linked polymers change with temperature, and exhibit a strong dependence on the temperature. By modifying the state equation of linear amorphous polymer, the equation that can be used to quantitatively describe the temperature dependence of CTEs of cross-linked polymers is established. By analyzing the temperature dependence of CTE, an equation is proposed to predict the CTEs of filled phenolic resins with different filler loadings at a specific temperature. The results of this study have contributed to a better understanding of the thermal expansion behaviors of glassy cross-linked polymers, and are of great significance in industrial practice.