Developing Superior Tough and Multifunctional Melamine-Formaldehyde Impregnated Paper through Si–O–C Hyperbranched Polysiloxane

The development of melamine-formaldehyde (MF) resin-impregnated paper has great significance in the decoration and construction industries. However, the MF-impregnated paper is prone to cracking and burning due to the inherent brittleness and poor flame retardancy of MF resin, restricting its wide application. Herein, we report a hyperbranched polysiloxane (HBPSi@EP) containing a flexible Si–O–C skeleton and tailored terminal epoxy using a simple, low-cost, and easily controlled ester exchange strategy to modify MF resin for fabricating high-performance and multifunctional impregnated paper. The break elongation of MF/HBPSi@EP impregnated paper increased by 186.5% since the energy dissipation of the hyperbranched structure and lubrication of the Si–O–C skeleton enhance its toughness. The tough MF/HBPSi@EP impregnated paper displayed outstanding cracking resistance during the thermal–cooling cycle. Meanwhile, the tensile strength of MF/HBPSi@EP impregnated paper reached 10 MPa, owing to the formation of a dense cross-linked structure by the hyperbranched epoxy in the HBPSi@EP. Notably, this impregnated paper exhibited good flame retardancy (B1-level in GB 8624-2012), cigarette burn resistance (Level 4 in GB/T 17657-2013), and wear resistance (1305.5 r). This facile and effective strategy can promote the development of tough, strong, and versatile coatings, film materials, and multifunctional composites.