https://cyberleninka.org/article/n/768408.pdf

Mechanical properties of graphene and graphene-based nanocomposites

Large-Scale Fabrication of Boron Nitride Nanosheets and Their Utilization in Polymeric Composites with Improved Thermal and Mechanical Properties

Hydrogels for biomedical applications.

The effect of graphene dispersion on the mechanical properties of graphene/epoxy composites

Unperturbed dimensions of stereoregular polymers.- Reinforcement of rubber by carbon black.- Transformations of phenolic antioxidants and the role of their products in the long-term properties of polyolefins.

Properties of polymers

In this study, carbon fibers (CFs) were coated with graphene nanoplatelets (GnP), using a robust and continuous coating process. CFs were directly immersed in a stable GnP suspension and the coating conditions were optimized in order to obtain a high density of homogeneously and well-dispersed GnP. GnP coated CFs/epoxy composites were manufactured by a prepreg and lay-up method, and the mechanical properties and electrical conductivity of the composites were assessed. The GnP coated CFs/epoxy composites showed 52%, 7%, and 19% of increase in comparison with non-coated CFs/epoxy composites, for 90° flexural strength, 0° flexural strength and interlaminar shear strength, respectively. Meanwhile, incorporating GnP in the CF/epoxy interphase significantly improved the electrical conductivity through the thickness direction by creating a conductive path between the fibers.

Mechanical and electrical properties of carbon fiber composites with incorporation of graphene nanoplatelets at the fiber–matrix interphase

The research activities in the development of recyclable and reprocessable covalently crosslinked networks, and the construction of polymers from renewable resources are both stemmed from the economical and environmental problems associated with traditional thermosets. However, there is little effort in combination of these two attractive strategies in material designs. This article reported a bio-based vitrimer constructed from isosorbide-derived epoxy and aromatic diamines containing disulfide bonds. The resulted dynamic epoxy resins showed comparable thermomechanical properties as compared to similar epoxy networks cured by traditional curing agent. Rheological tests demonstrated the fast stress relaxation of the dynamic network due to the rapid metathesis of disulfide bonds at temperature higher than glass transition temperature. This feature permitted the recycling and reprocessing of the fragmented samples for several times by hot press. The dynamic epoxy resins also exhibited shape-memory effect, and it is demonstrated that the shape recovery ratio could be readily adjusted by controlling the stress relaxation in the temporary state at programming temperature. Moreover, the degradability of the dynamic epoxy resins in alkaline aqueous solution was also demonstrated. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017, 55, 1790–1799

Bio-based epoxy vitrimers: Reprocessibility, controllable shape memory, and degradability

The two-parameter Weibull distribution does not always adequately describe the experimental bast fibre strength at different gauge lengths. For this reason, it was modified by incorporating the diameter variation of jute fibres in this paper. The fibre diameter was measured with an optical microscope. The three-parameter Weibull model was also used to compare with the modified model. It was found that as the fibre diameter variation increased the tensile strength of the jute fibre decreased. The strength predicted by modified Weibull distribution was more accurate than that of the two conventional models. In addition, the breaking strength of jute fibre was less sensitive to gauge length than that of cotton fibre because the breaking of jute filament involves ultimate cells breaking repeatedly and matrix cracking.

Study on the breaking strength of jute fibres using modified Weibull distribution

To support rapid advancements in the field of biocomposites, it is necessary to exploit novel fillers that are biocompatible, multifunctional and easy to obtain. In this work, polydopamine particles (PDAPs) have been reported as a filler for constructing polymer composites. PDAPs with average diameters of about 1040 and 310 nm were first prepared by a convenient oxidative polymerization of dopamine, then PDAP/poly(vinyl alcohol) (PVA) composites were prepared through a traditional solution-casting method. Measurements on the resultant composites confirmed strong interactions between the PDAPs and PVA chains and the good dispersion of PDAPs throughout the matrix. It was found that the PDAPs could promote the crystallization of PVA and, thus, greatly improve the mechanical properties of the composites. TGA results showed that both the initial and maximum decomposition temperatures of PVA were significantly increased by the addition of PDAPs. Moreover, the composites showed superior antioxidant properties and UV-shielding efficiency compared to neat PVA. The effect of particle size on the reinforcement was also evaluated. The results suggested that PDAPs could be a good candidate for use in multifunctional composites.

Junrong Yu

Papers

Mechanical and electrical properties of carbon fiber composites with incorporation of graphene nanoplatelets at the fiber–matrix interphase

Bio-based epoxy vitrimers: Reprocessibility, controllable shape memory, and degradability

Study on the breaking strength of jute fibres using modified Weibull distribution

Polydopamine particles for next-generation multifunctional biocomposites

Tuning the interface of graphene platelets/epoxy composites by the covalent grafting of polybenzimidazole