Controlled synthesis and toughening mechanisms of an all-purpose hyperbranched modifier, which can form non-phase-separated networks with simultaneous enhancements in Tg, modulus, impact and tensile strengths.

Synthesis of epoxide-terminated hyperbranched polyethers (EHBPEs) with different backbone stiffness and molecular weight (MW) are obtained using simple one-pot A 2 +B 3 approach. When used as tougheners for DGEBA/TETA system, non-phase-separated cured networks are always obtained. Effects of MW and backbone stiffness on the toughening performance were systematically investigated. Among the EHBPEs studied, EHBPE-4C which has the lowest MW and stiffest backbone and EHBPE-10C 10 which has the highest MW and most flexible backbone can simultaneously improve toughness, tensile strength, and T g . In contrast, addition of EHBPE-6C and EHBPE-8C, which have medium MW and backbone stiffness, lead to incomplete cure and cannot improve or worsen the toughness and tensile strength. Both stiffness and MW of hyperbranched polyether play important roles in determining the crosslink density and structure of non-phase-separated networks, which dictate the toughness strength and 15

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Using competing reactions to achieve controllability in hyperbranched polymers and Tg mixing laws in hyperbranched blends and copolymers.