Abstract: Matrix resin crosslinking reactions and the coupled effects of thermal expansion during curing lead to both irreversible chemical shrinkage and reversible physical thermal shrinkage in thermosetting composites, significantly impacting the deformation accuracy and residual stress distribution of molded parts. This study first explores the thermal expansion and curing shrinkage of thermosetting resins and their composite materials, clarifying how thermal expansion and contraction variations in carbon fiber reinforced polymer (CFRP) influence engineering applications. Then, using a CFRP plate with a stacking sequence of [0, 45, 90, -45]2s as the test specimen, the linear coefficient of thermal expansion (CTE) of the CFRP plate was measured with the ejection method across a temperature range from 20°℃ to 125°℃. The results showed that deviation between the measured average CTE and the theoretical value calculated using the Halpin model is relatively small, thus confirming the reliability of this measurement method for engineering purposes.

Key words: CFRP; cure; thermal expansion; chemical shrinkage; CTE measurement