Constructing nano SiO2‐anchored hyperbranched polymer hybrid architectures for thermosetting epoxy systems with outstanding mechanical property

Abstract

AbstractA hybrid architecture system was developed via in situ formation of SiO2 nanoparticles in the cavities of COOH‐terminated hyperbranched aromatic polyester (CHBPE). Results show that SiO2 nanoparticles can be successfully anchored in the cavities of CHBPE owing to the hyperbranched structure of CHBPE. The resulting CHBPE‐SiO2 system is applied to epoxy (EP) resins using 4,4′‐diaminodiphenyl sulfone (DDS) as curing agent. Because –COOH groups in CHBPE‐SiO2 system can react with epoxy groups, the conversion of epoxy groups in EP/CHBPE‐SiO2 systems can be improved, and the strong interface interaction between EP matrix and CHBPE‐SiO2 can be realized. The resulting EP/CHBPE‐SiO2 composites have excellent mechanical property. When the contents of CHBPE‐SiO2 are 8%–20%, the impact strengths, the flexural strengths and the tensile strengths of EP/CHBPE‐SiO2 composites can reach 24–46 kJ/m2, 121–165 MPa and 57–71 MPa, respectively, which are 16.1–31.9‐fold, 4.0–5.9‐fold and 8.9–11.3‐fold higher than those of pure EP, respectively. EP/16%CHBPE‐SiO2 composites have the optimal comprehensive mechanical property. The initial thermal decomposition temperature at 5 wt% weight loss (Tdi) and glass‐transition temperature (Tg) of EP composites can increase by 70–84°C and 30–43°C, respectively, after introducing 8%–20% CHBPE‐SiO2. Moreover, the dielectric constants of EP composites with 8%–20% CHBPE‐SiO2 decrease by 3%–11% as compared to pure EP. The high dispersion of SiO2 in EP/CHBPE‐SiO2 composite and the strong interface interaction between EP matrix and CHBPE‐SiO2 can contribute to the outstanding comprehensive property of EP/CHBPE‐SiO2 composite.