Study on synthesis and demolding performance of polyethylene glycol fatty acid mold release agents

Abstract Release agent is an indispensable kind of processing aids for composite molding. A kind of release agents was synthesized by using polyethylene glycol (M n = 200, 300, 400) with different molecular weight as raw material, reacting with fatty acids with different carbon chains length (lauric acid, myristic acid, hexadecanoic acid, and stearic acid), and further crosslinking with phosphoric acid. The chemical structure of the synthesized release agent was confirmed by FT‐IR and 1 H‐NMR. Through the performance test of the synthesized demolding agent, five release agents with excellent performance were screened out. The results showed: The release agents can be well dissolved in ethanol, a green and environment‐friendly solvent. The molecular weight was 480–630. The release agent's acid value was between 0.05 and 0.06KOH/(mg/g). The peeling strength was 0.066–0.087 MPa and the interlaminar shear strength was 1.101–1.323 MPa. The film‐forming time of the release agents on the mold was 1.5 min–3.5 min. The number of demolding was 16–20 times. The micro‐morphology of the resin surface demolded by NnP release agent synthesized in the present study and Meishu brand release agent widely‐used in the market was observed and compared by scanning electron microscope, indicating that the surface morphology of the resin demolded by NnP release agent was smoother after release. So the NnP release agents can be used in actual production.