Polysilazane‐Based Coatings with Anti‐Adherent Properties for Easy Release of Plastics and Composites from Metal Molds. Issue 10 (15th April 2020)

• Record Type: Journal Article
• Authors: Barroso, Gilvan; Döring, Michael; Horcher, Alexander; Kienzle, Andreas; Motz, Günter
• Is Part Of: Advanced materials interfaces. Volume 7:Issue 10(2020)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2020-04-15
• Subjects: anti‐adherent coatings -- carbon‐fiber reinforced plastics -- mold release coatings -- polysilazanes -- poly(tetrafluoroethylene) (PTFE); Materials science -- Periodicals; 620.11
• DOI: 10.1002/admi.201901952
• Languages: English
• ISSNs: 2196-7350

Abstract

Abstract: Polysilazanes are excellent coating materials, because of their self‐crosslinking in air at low temperatures, high chemical and thermal stability, elevated hardness, and excellent adhesion to many different substrates. Therefore, coatings of two chemically different polysilazanes (crosslinked Durazane 1800 (HTTS)/perhydropolysilazane (PHPS)) are deposited by either dip or spray coating and crosslinked at 200 or 300 °C in air to investigate the chemical composition, surface energy, and coating adhesion in dependency on the precursor type and crosslinking temperature. The silazane HTTS possesses a higher amount of nonpolar organic groups resulting in a lower surface free energy. The anti‐adherence properties are investigated by using a phenolic resin via pull‐off adhesion, which is slightly reduced from 13 MPa for uncoated aluminum to less than 10 MPa for HTTS coated substrates. The addition of different amounts of poly(tetrafluoroethylene) (PTFE) particles causes a remarkable reduction of the surface free energy leading to a strongly reduced pull‐off adhesion of less than 4 MPa of the phenolic resin from the HTTS/PTFE coated substrates. The anti‐adherent properties remain even after repeated pull‐off tests. Because of the excellent properties, the HTTS/PTFE coatings are a very suitable system for easy mold release of plastic parts from metal molds and to replace commercial nonstick PTFE coatings. Abstract : Anti‐adherent coating systems based on polysilazanes and poly(tetrafluoroethylene) (PTFE) particles applied by spray coating and annealed at 300 °C are developed. The low surface free energy leads to high contact angles with water (145°) and diiodomethane (120°). Consequently, the adhesion to a phenolic resin is reduced to 3 in comparison to 12 MPa to uncoated aluminum.