Factors affecting thermal conductivities of the polymers and polymer composites: A review

Phosphorus-containing flame retardant epoxy thermosets: Recent advances and future perspectives

Superhydrophobic cellulose-based products have immense potential in many industries where plastics and other polymers with hydrophobic properties are used. Superhydrophobic cellulose-based plastic is inherently biodegradable, renewable and non-toxic. Finding a suitable replacement of plastics is highly desired since plastics has become an environmental concern. Despite its inherent hydrophilicity, cellulose has unparalleled advantages as a substrate for the production of superhydrophobic materials which has been widely used in self-cleaning, self-healing, oil and water separation, electromagnetic interference shielding, etc. This review includes a comprehensive survey of the progress achieved so far in the production of super-hydrophobic materials based on cellulose and fiber networks. The method-ologies and applications of superhydrophobic-modified cellulose and fiber networks are emphasized. Overall, presented herein is targeting on summarizing some of the aspects that are critical to advance this evolving field of science which may provide new ideas for the developing and exploring of superhydrophobic and green-based materials.

Superhydrophobic modification of cellulose and cotton textiles: Methodologies and applications

With the development of science and technology, microelectronic components have evolved to become increasingly integrated and miniaturized. As a result, thermal management, which can seriously impact the function, reliability, and lifetime of such components, has become a critical issue. Recently, the use of polymer-based thermal interface materials (TIMs) in thermal management systems has attracted considerable attention in view of the superior comprehensive properties of the former. Compared with designing and fabricating a polymer with an intrinsically high thermal conductivity, a more effective and widely used strategy for improving the heat conductivity is to fill a polymer matrix with a thermally conductive filler. Specifically, three-dimensional (3D) interconnected heat-conductive networks can increase the thermal conductivity (k) of polymers more effectively than dispersed fillers can, owing to their intrinsic continuous structures. In this review, we first introduce the heat conduction mechanisms and the problems associated with polymer-based TIMs fabricated using engineering polymer chains and traditional filling methods. Next, we discuss the advantages and mechanisms of 3D interconnected heat-conductive networks for preparing thermally conductive polymer-based composites. In addition, we highlight new advancements in the design and fabrication of 3D thermally conductive networks as well as their application in improving the k of polymers. Our exhaustive review of 3D interconnected networks includes graphene, carbon nanotubes, boron nitride, metal and other 3D hybrid architectures. The key structural parameters and control methods for improving the thermal properties of polymer composites are outlined. Finally, we summarize some effective strategies and possible challenges for the development of polymer-based thermally conductive composites via integration with 3D interconnected networks.

Three-dimensional interconnected networks for thermally conductive polymer composites: Design, preparation, properties, and mechanisms

To improve the dispersion of graphene oxide (GO) nanosheets in sizing agent and to enhance the interfacial adhesion between GO and epoxy, GO nanosheets were chemically modified with cyanuric chloride (TCT) and diethylenetriamine (DETA). The functionalized GO (i.e. GO-TCT-DETA) with different contents was introduced into the carbon fiber (CF) interface by sizing process. The uniform distribution of GO sheets on CF surface and the enhancement of surface roughness were obtained. Moreover, significant enhancements (i.e., 104.2%, 100.2%, and 78.3%) of interfacial shear strength (IFSS), interlaminar shear strength (ILSS), and flexural properties were achieved in the composites with only 1.0 wt% GO-TCT-DETA sheets introduced in the fiber sizing. The GO-TCT-DETA in the interface region enhanced the stress being transferred effectively and the local stress concentrations being relieved. This study indicates that the utilization of functionalized GO is one of the alternative approaches for controlling the fiber-matrix interface and improving the mechanical properties of CF epoxy composites.

Reinforcing carbon fiber epoxy composites with triazine derivatives functionalized graphene oxide modified sizing agent

Enhancing interfacial properties of carbon fibers reinforced epoxy composites via Layer-by-Layer self assembly GO/SiO2 multilayers films on carbon fibers surface

A DOPO-based phosphorus-nitrogen flame retardant bio-based epoxy resin from diphenolic acid: Synthesis, flame-retardant behavior and mechanism

The deposition of graphene oxide (GO) onto carbon fibers (CF) surface to form a hierarchical reinforcement structure has been achieved via various bonding types: van der Waals forces, zwitterionic interactions and covalent bonds. The functional groups, surface elements, contents of introduced GO, surface structures, morphologies and wettability of GO-deposited CF were characterized by FT-IR, XPS, TGA, Raman, SEM and Dynamic contact angle meter, respectively. Covalently grafting GO onto CF (CF-c-GO) has been proved to be the most effective way to improve the interfacial properties. Compared with pristine CF, the flexural strength, interlaminar shear strength and interfacial shear strength of CF-c-GO composites were increased by 28.7%, 22.7% and 50.6%, respectively. The CF-GO hierarchical composites featured a stronger interfacial bonding as evidenced by the fracture surface analysis, which demonstrated the enhancement in interfacial properties of hierarchical thermoplastic composites.

Improving interfacial properties of hierarchical reinforcement carbon fibers modified by graphene oxide with different bonding types

In this study, a series of soluble aminated polyether-ether-ketone (PEEK-NH2) with good compatibility were designed. Novel water-based sizing agents were then prepared by emulsion/solvent evaporation method, which were selected as CF surface modifiers to improve the interfacial properties of CF/PEEK composites. TGA and DSC results showed that PEEK-NH2 exhibit excellent thermal properties, and the Tg was increased by up to 30.9 °C. The particle diameters of sizing agents range from 54.3 to 73.6 nm, and the contact angles of modified CF were significantly decreased. According to the interfacial properties results, PEEK–NH2–35 presented the most effective reinforcing effect, the interlaminar shear strength and flexural strength were increased by 43.1% and 62.2%, as compared to un-sized CF composites. Moreover, the interfacial strengthening mechanisms of sizing agent was investigated. The improved interfacial adhesion benefits from PEEK-NH2 which performs as effective stress transfer bridge at the interface.

Interfacial enhancement of CF/PEEK composites by modifying water-based PEEK-NH2 sizing agent

A novel copper/carbon nanotube/carbon fiber (Cu/CNT/CF) multiscale reinforcement was successfully achieved using a one-step electrophoretic deposition technique in which CNT was introduced via two techniques. Two stabilized electrolytes containing CNT of distinct charge character were prepared to investigate the effect of CNT to the thermal/electrical conductivity and interlaminar shear strength (ILSS) of the composites. The positively charged CNT composites showed increases of 359.2%, 2761% and 34.5% for thermal conductivity and electrical conductivity in the through-thickness direction and the ILSS, respectively, in comparison with de-sized CF composites. Contrast with the two-step method, the preparation time of the one-step method has been shortened to one-fifth, and the connections between the Cu and CNT were compacted to improve the conductivity of the composites. Moreover, Cu/CNT/CF prepared according to the one-step method was highly compatible with vacuum-assisted resin infusion technology and provided a route for preparing multifunctional composites that could be easily scaled up.

One-step electrodeposition of Cu/CNT/CF multiscale reinforcement with substantially improved thermal/electrical conductivity and interfacial properties of epoxy composites

Mengjie Zhang

Papers

Enhancing interfacial properties of carbon fibers reinforced epoxy composites via Layer-by-Layer self assembly GO/SiO2 multilayers films on carbon fibers surface

A DOPO-based phosphorus-nitrogen flame retardant bio-based epoxy resin from diphenolic acid: Synthesis, flame-retardant behavior and mechanism

Improving interfacial properties of hierarchical reinforcement carbon fibers modified by graphene oxide with different bonding types

Interfacial enhancement of CF/PEEK composites by modifying water-based PEEK-NH2 sizing agent

One-step electrodeposition of Cu/CNT/CF multiscale reinforcement with substantially improved thermal/electrical conductivity and interfacial properties of epoxy composites