Poly(styrene-maleic anhydride) functionalized graphene (FG) and functionalized carbon nanotubes (FCNTs) were fabricated using in situ polymerization. The FG and FCNTs were used in the in situ ring-opening polymerization of e-caprolactam to form polyamide 6 (PA6)/FG/FCNTs composites. Both PA6 and the composite fibers were melt-spun in a piston spinning machine. The structure and properties of the composites and the fibers were characterized. The experimental results demonstrate that the mixture of graphene and carbon nanotubes exhibits good dispersion in a PA6 matrix. No obvious aggregation of graphene or CNTs was observed inside the composite fibers. The mechanical properties of PA6 are improved by inserting FG/FCNTs into the composite fibers, in particular, the tensile strength of composite fiber containing FG (0.2 wt%)/FCNTs (0.3 wt%) is 2.4 times that of pure PA6, and Young's modulus is 132 % higher than that of the control. The crystallinity of the composite fibers is also enhanced. With the improvement of the tensile strength and Young's modulus of PA6, its application will be expanded.

One of the advantages of cement and the cement concrete industry in sustainability is the ability to utilize large amounts of industrial solid wastes such as fly ash and ground granulated blast furnace slag. Tailings are solid wastes of the ore beneficiation process in the extractive industry and are available in huge amounts in some countries. This paper reviews the potential utilization of tailings as a replacement for fine aggregates, as supplementary cementitious materials (SCMs) in mortar or concrete, and in the production of cement clinker. It was shown in previous research that while tailings had been used as a replacement for both fine aggregate and cement, the workability of mortar or concrete reduced. Also, at a constant water to cement ratio, the compressive strength of concrete increased with the tailings as fine aggregate. However, the compressive strength of concrete decreased as the replacement content of the tailings as SCMs increased, even whentailings were ground into smaller particles. Not much research has been dedicated to the durability of concrete with tailings, but it is beneficial for heavy metals in tailings to stabilize/solidify in concrete. The clinker can be produced by using the tailings, even if the tailings have a low SiO2 content. As a result, the utilization of tailings in cement and concrete will be good for the environment both in the solid waste processing and virgin materials using in the construction industry.

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In this study, poly(styrene–maleic anhydride) functionalized graphene oxide (SMAFG) was fabricated with in situ polymerization. The sample was characterized with Raman spectroscopy, Fourier transform infrared spectroscopy, thermogravimetric analysis, transmission electron microscopy, and ultraviolet–visible absorption. The results of the experiments show that the thermal stability of SMAFG was improved significantly, and it also possessed a good dispersion in N,N‐dimethylformamide, N,N‐dimethylacetamide, aniline, and certain organic solvents. The calculated Hildebrand parameter of SMAFG was 23.8 MPa1/2. This new method will broaden the applications of graphene, and the experiment showed that it could effectively improve the strength of polyamide 6 (PA6) compared with the pure PA6 fiber. The tensile strength of the SMAFG/PA6 composite fiber improved 29%, and the Young's modulus improved 33%, so this kind of functionalized graphene oxide can be used in the preparation of polymeric composites. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 41987.