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

A hybrid architecture system was developed via in situ formation of SiO 2 nanoparticles in the cavities of COOH-terminated hyperbranched aromatic polyester (CHBPE). Results show that SiO 2 nanoparticles can be successfully anchored in the cavities of CHBPE owing to the hyperbranched structure of CHBPE. The resulting CHBPE-SiO 2 system is applied to epoxy (EP) resins using 4,4′-diaminodiphenyl sulfone (DDS) as curing agent. Because –COOH groups in CHBPE-SiO 2 system can react with epoxy groups, the conversion of epoxy groups in EP/CHBPE-SiO 2 systems can be improved, and the strong interface interaction between EP matrix and CHBPE-SiO 2 can be realized. The resulting EP/CHBPE-SiO 2 composites have excellent mechanical property. When the contents of CHBPE-SiO 2 are 8%–20%, the impact strengths, the flexural strengths and the tensile strengths of EP/CHBPE-SiO 2 composites can reach 24–46 kJ/m 2 , 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-SiO 2 composites have the optimal comprehensive mechanical property. The initial thermal decomposition temperature at 5 wt% weight loss ( T di ) and glass-transition temperature ( T g ) of EP composites can increase by 70–84°C and 30–43°C, respectively, after introducing 8%–20% CHBPE-SiO 2 . Moreover, the dielectric constants of EP composites with 8%–20% CHBPE-SiO 2 decrease by 3%–11% as compared to pure EP. The high dispersion of SiO 2 in EP/CHBPE-SiO 2 composite and the strong interface interaction between EP matrix and CHBPE-SiO 2 can contribute to the outstanding comprehensive property of EP/CHBPE-SiO 2 composite.