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Interfacial interaction is one of the most important factors in the construction of high-performance graphene-based elastomer composites. In this paper, graphene/poly (styrene-b-isoprene-b-styrene) (SIS) composites were prepared with solution mixing followed by an evaporation-induced self-assembly process. Various techniques such as scanning electron microscopy, UV-vis absorption spectra, tensile testing, Shore A hardness, surface resistance, thermal conductivity, and thermogravimetric analysis were conducted to characterize the microstructure and properties of the obtained composites. The results showed that the π–π stacking interfacial interaction between phenyl groups of SIS and graphene play an important role in the properties’ improvement, and the effect of interfacial interaction on the properties was revealed.

The quantitative characterization of microstructure is most desirable for the establishment of structure-property relationships in polymer nanocomposites. In this work, the effects of graphene on the microstructure, mechanical, electrical, and thermal properties of the obtained graphene/polyethylene (PE) composites were investigated. In order to reveal the structure-performance relationship of graphene/PE composites, especially for the effects of the relative free volume fraction (fr) and interfacial interaction intensity (β), positron annihilation lifetime spectroscopy (PALS) was employed for its quantitative description. The relative free volume fraction fr gives a good explanation of the variation for surface resistivity, melting temperature, and thermal stability, and the variation of tensile strength and thermal conductivity agree well with the results of interfacial interaction intensity β. The results showed that fr and β have a significant effect on the properties of the obtained graphene/PE composites, and the effect on the properties was revealed.

Hydraulic fracturing is an important technology for the exploitation of unconventional oil or gas reservoirs. In order to increase the production of oil or gas, ultra-lightweight proppants with a high compressive strength are highly desirable in hydraulic fracture systems. In this work, a new type of ultra-lightweight proppant, poly(styrene-co-methyl methacrylate)/fly ash (poly(St-co-MMA)/FA) composites with a high compressive strength were prepared via in situ suspension polymerization. The Fourier transform infrared (IR) and X-ray powder diffraction (XRD) analyses confirmed that the poly(St-co-MMA)/FA composites were successfully prepared. The morphology analysis indicated that the composite microspheres show good sphericity, and FA powder was evenly dispersed in the matrix. The apparent density of the microspheres was between 1 and 1.3 g/cm3, which is suitable for hydraulic fracturing. Furthermore, the compressive strength and thermostability were dramatically improved with the incorporation of FA, which could withstand high pressures and temperatures underground. The obtained poly(St-co-MMA)/FA composite microspheres are promising for application as an ultra-lightweight (ULW) proppant in oil or gas exploitation, which provides a new approach for the design of high performance proppants.

The incorporation of graphene oxide (GO) into a polymeric drug carrier can not only enhance the loading efficiency but also reduce the initial burst and consequently improve the controllability of drug release. Firstly, 5-fluorouracil (5-Fu)-loaded hydroxypropyl cellulose/chitosan (HPC/CS@5-Fu) and GO/HPC/CS@5-Fu aerogels were successfully fabricated through chemical cross-linking with glutaraldehyde. Then, the obtained aerogels were characterized using scanning electron microscopy (SEM), Fourier transform infrared (FITR), X-ray diffraction (XRD), differential scanning calorimetry (DSC), thermogravimetry (TG), and the effect of HPC and GO content on the drug loading (DL) and encapsulation efficiency (EE) for the two aerogels were investigated, respectively. Finally, the drug release behavior of the GO/HPC/CS@5-Fu aerogels with different GO content was evaluated at two different pH values, and four kinds of kinetic models were used to evaluate the release behavior.