Recyclable Curcumin-Based Bioepoxy Resin with On-Demand Chemical Cleavability.

We synthesized a novel curcumin-based bioepoxy resin by introducing epichlorohydrin (ECH) into the hydroxyl groups of curcumin and analyzed it using Fourier transform infrared spectroscopy (FTIR) and nuclear magnetic resonance (NMR). The epoxy equivalent weight (EEW) was determined based on a reaction with sodium hydroxide (NaOH) through titration, and the actual curing process was conducted after exploring the optimal conditions using an amine-based curing agent through dynamic scanning in differential scanning calorimetry (DSC) and isotherm analysis. The cured epoxy resin had a tensile strength, Young's modulus, and glass transition temperature (Tg) of 33 MPa, 1.4 GPa, and 86 °C, respectively. Interestingly, the diunsaturated ketone contained in the epoxy resin showed on-demand chemical cleavability, in that it had been decomposed into an aldehyde and ketone only after having been converted to a hydroxyl ketone through an oxidation reaction. The results of this study can significantly contribute to improving the eco-friendliness and recyclability of epoxy resins used in fields requiring long-term stability and chemical resistance.

Vitrimer Nanocomposites for Highly Thermal Conducting Materials with Sustainability.

Vitrimers, as dynamic covalent network polymers, represent a groundbreaking advancement in materials science. They excel in their applications, such as advanced thermal-conductivity composite materials, providing a sustainable alternative to traditional polymers. The incorporation of vitrimers into composite fillers enhances alignment and heat passway broadly, resulting in superior thermal conductivity compared to conventional thermosetting polymers. Their dynamic exchange reactions enable straightforward reprocessing, fostering the easy reuse of damaged composite materials and opening possibilities for recycling both matrix and filler components. We review an overview of the present advancements in utilizing vitrimers for highly thermally conductive composite materials.

Novel Latent Heat Storage Systems Based on Liquid Metal Matrices with Suspended Phase Change Material Microparticles.

Phase change materials (PCMs) are considered useful tools for efficient thermal management and thermal energy utilization in various application fields. In this study, a colloidal PCM-in-liquid metal (LM) system is demonstrated as a novel platform composite with excellent latent heat storage capability, high thermal and electrical conductivities, and unique viscoelastic properties. In the proposed formulation, eutectic Ga-In is utilized as a high-thermal-conductivity and high-fluidity liquid matrix in which paraffinic PCM microparticles with various solid-liquid phase transition temperatures are suspended as fillers. Good compatibility between the fillers and matrix is achieved by the nanosized inorganic oxides (titania) adsorbed at the filler-matrix interface; thus, the composite is produced via simple vortex mixing without tedious pre- or post-processing. The composite shows unique trade-off effects among various properties, i.e., elastic modulus, yield stress, density, thermal conductivity, and melting or crystallization enthalpy, which can be easily controlled by varying the contents of the suspended fillers. A Joule heating device incorporating the composite exhibits improved electrothermal performance owing to the synergy between the high electrical conductivity and latent heat storage capability of the composite. The proposed platform may be exploited for the rational design and facile manufacture of high-performance form-factor-free latent heat storage systems for various potential applications such as battery thermal management and flexible heaters.

Advances in Liquid Crystalline Epoxy Resins for High Thermal Conductivity.

Epoxy resin (EP) is one of the most famous thermoset materials. In general, because EP has a three-dimensional random network, it possesses thermal properties similar to those of a typical heat insulator. Recently, there has been substantial interest in controlling the network structure of EP to create new functionalities. Indeed, the modified EP, represented as liquid crystalline epoxy (LCE), is considered promising for producing novel functionalities, which cannot be obtained from conventional EPs, by replacing the random network structure with an oriented one. In this paper, we review the current progress in the field of LCEs and their application to highly thermally conductive composite materials.

Prosthetic reconstruction with an obturator using swing-lock attachment for a patient underwent maxillectomy: A clinical report.

Patients who underwent resection of maxilla due to benign or malignant tumor, or accident will have defect in palatal area. They get retention, support and stability from remaining tissues which are hardly optimal. The advantage of swing-lock attachment design is having multiple contacts on labial and lingual side of the abutment teeth by retentive strut and palatal bracing component. Because the force is distributed equally to abutment teeth, abutment teeth of poor prognosis can be benefited from it. It is also more advantageous to cover soft tissue defects which are hard to reach with conventional prosthesis. A 56-year-old female patient who had undergone a maxillectomy due to malignant melanoma complaining of loose and unstable surgical obturator. Surveyed crowns were placed on #12, 26, and 27. Teeth #11, 21, 22, and 23 had lingual rest seat and #24 had mesial rest seat to improve stability and support of the obturator. This clinical report presents the prosthetic management of a patient treated with obturator on the maxilla using swing-lock attachment to the remaining teeth.