A one‐pot reaction between Cu(BF4)2·xH2O and 4‐mercaptobenzoic acid in acetone or methanol gives rise to the formation of lamellar microcrystals of two Cu(I)‐thiophenolate‐based coordination polymers (CPs) with the formulas [CuCT]n (1) (CT = 4‐carboxy‐thiophenolate) and [CuMCT]n (2) (MCT = 4‐methoxycarbonyl‐thiophenolate). Both 1 and 2 show a reversible luminescent thermochromic behavior upon cooling, changing their color from pale yellow to green to orange in the case of 1, and from pale orange to green in the case of 2. It is shown that the lamellar character of these crystals, which exhibit micrometer lateral dimensions and sub‐micrometer/nanometer thicknesses, allows processing them with an organic polymer such as polyvinylidene difluoride (PVDF) to form thermochromic 1@PVDF and 2@PVDF thin films. These thermal stimuli‐responsive thin films are freestanding, free of macroscopic defects, and robust under mechanical bending stress, opening up the possibility to use them in, for example, 2D imaging sensor films.
The incorporation of well-dispersed graphene oxide (GO) and graphene (G) has been demonstrated as a promising solution to improve the mechanical performance of polymethyl methacrylate (PMMA) bone cements in an attempt to enhance the long-term survival of the cemented orthopaedic implants. However, to move forward with the clinical application of graphene-based PMMA bone cements, it is necessary to ensure the incorporation of graphene-based powders do not negatively affect other fundamental properties (e.g., thermal properties and biocompatibility), which may compromise the clinical success of the implant. In this study, the effect of incorporating GO and G on thermal properties, biocompatibility, and antimicrobial activity of PMMA bone cement was investigated. Differential scanning calorimetry studies demonstrated that the extent of the polymerisation reaction, heat generation, thermal conductivity, or glass transition temperature were not significantly (p > 0.05) affected by the addition of the GO or G powders. The cell viability showed no significant difference (p > 0.05) in viability when MC3-T3 cells were exposed to the surface of G- or GO-PMMA bone cements in comparison to the control. In conclusion, this study demonstrated the incorporation of GO or G powder did not significantly influence the thermal properties or biocompatibility of PMMA bone cements, potentially allowing its clinical progression.
The surface modification and adhesive bonding of a carbon fiber reinforced plastic (CFRP) composite has been investigated. Wettability studies showed that plasma-treated specimens provide a significant increment in the surface energy, relative to untreated material. The surface modification resulted in significantly improved adhesion between the composite and an applied toughened acrylic adhesive; a considerable increase in fracture energy was observed following grit blasting and grit blasting plus silane treatments. Specimens treated with atmospheric plasma showed a slight increment in fracture energy, usually failing adhesively. The durability was tested using a wedge test. Specimens degreased and treated with atmospheric plasma showed the greatest crack growth and failed in an adhesive mode.
1 January 2010 in Journal of Adhesion Science and Technology
The surface modification and adhesive bonding of a bidirectional glass reinforced polymer (GRP) composite have been investigated. Wettability studies showed that grit-blasted and plasma-treated spe...