Fuente: Journal of applied polymer Lugar: RESEARCH ARTICLE This article aims to develop an efficient toughening method for cycloaliphatic epoxy resin. By capping hydroxyl-terminated silicone with polyether alcohol under the action of a catalyst, an organosilicon prepolymer containing flexible long chains is synthesized and introduced into the epoxy system. Mechanical property tests show that when the addition amount is C-80, the tensile strength reaches 13.87 MPa, and the elongation at break is 94.17%, which is 19.88 times higher than that of EEC epoxy resin. The results indicate that introducing flexible long-chain polyether alcohol to cap polydimethylsiloxane can effectively enhance the molecular chain movement ability, thereby achieving efficient toughening of epoxy resin.

ABSTRACT
We present a highly effective approach for enhancing the toughness of alicyclic epoxy resins through the integration of a synthesized organosilicon prepolymer (HPEPS–EEC) characterized by flexible long chains. This prepolymer was synthesized via a catalyzed end-capping reaction involving hydroxyl silanes and polyether alcohols. Structural verification was conducted using Fourier-transform infrared (FT-IR) spectroscopy and nuclear magnetic resonance (NMR) analyses. As the content of hydroxyl-polyether-terminated polydimethylsiloxane increased, the modified resin demonstrated a decrease in tensile strength but a significant increase in elongation at break, accompanied by reduced light transmittance. An optimal incorporation of C-80 resulted in a tensile strength of 13.87 MPa and an elongation at break of 94.17%, representing a 19.88-fold enhancement in elongation at break compared to the unmodified EEC resin. These findings substantiate that the incorporation of flexible long chains enhances molecular mobility, thereby facilitating effective toughening of the resin.