Yingyan Mao

Fabrication of highly oriented hexagonal boron nitride nanosheet/elastomer nanocomposites with high thermal conductivity.

A homogeneous dispersion of hexagonal boron nitride nanosheets (BNNSs) in elastomers is obtained by solution compounding methods, and a high orientation of BNNSs is achieved by strong shearing. The composites show high thermal conductivities, especially when BNNS loading exceeds 17.5 vol%, indicating that the material is promising for thermal-management applications which need high thermal conductivity, low dielectric constant, and adequate softness.

High Performance Graphene Oxide Based Rubber Composites

In this paper, graphene oxide/styrene-butadiene rubber (GO/SBR) composites with complete exfoliation of GO sheets were prepared by aqueous-phase mixing of GO colloid with SBR latex and a small loading of butadiene-styrene-vinyl-pyridine rubber (VPR) latex, followed by their co-coagulation. During co-coagulation, VPR not only plays a key role in the prevention of aggregation of GO sheets but also acts as an interface-bridge between GO and SBR. The results demonstrated that the mechanical properties of the GO/SBR composite with 2.0 vol.% GO is comparable with those of the SBR composite reinforced with 13.1 vol.% of carbon black (CB), with a low mass density and a good gas barrier ability to boot. The present work also showed that GO-silica/SBR composite exhibited outstanding wear resistance and low-rolling resistance which make GO-silica/SBR very competitive for the green tire application, opening up enormous opportunities to prepare high performance rubber composites for future engineering applications.

Enhancing graphene oxide reinforcing potential in composites by combined latex compounding and spray drying

A new strategy was developed to prepare graphene oxide/styrene-butadiene rubber (GO/SBR) composites with highly exfoliated GO sheets and strong interfaces. In particular, GO/SBR microparticles, in which exfoliated GO sheets (with a thickness of ∼1 nm and diameter of tens of nanometers) are trapped in a well-dispersed state throughout the SBR matrix, were made by a combined latex-compounding and spray-drying method. Subsequently, a chemical bridge between GO and rubber matrix through KH550 and Si69 was built during vulcanization, and the interfacial strength of the cured GO/SBR composite was remarkably improved. Due to the highly exfoliated structure and the strong interface, the GO/SBR composite exhibited 7.8 times higher modulus at 300% strain and 6.4 times higher tensile strength compared with cured pure SBR. The combined latex-compounding and spray-drying method presented here is feasible and water-mediated and has great potential for industrial applications.

Preparation of Gd2O3 nano-flakes and fabrication/evaluation of their X-ray shielding rubber nanocomposites with improved mechanical properties

The aim of this study was to explore the development of lead-free X-ray shielding rubber nanocomposites with improved mechanical properties. In specific, gadolinium oxide (Gd2O3) nano-flakes (with thickness of ∼20 nm and sizes being tens of nanometers) were first prepared via the co-precipitation spray drying method; subsequently, the prepared Gd2O3 nano-flakes were uniformly dispersed into nitrile butadiene rubber (NBR) followed by vulcanization for the fabrication of flexible and lightweight X-ray shielding nanocomposites. Compared with the Gd2O3/NBR conventional composites made from a Gd2O3 powder with particle sizes in the range of 5–20 µm, the fabricated Gd2O3/NBR nanocomposites exhibited significantly higher tensile strength, Shore A hardness, and X-ray shielding properties while the rubbery characteristic (i.e. elasticity) was retained.