Solvent-Free Environmentally Friendly Method to Prepare Thermo-Reversible Fully Bio-Based Elastomers

Most rubber products come from petrochemical resources, which are increasingly in short supply. Rubber products that formed irreversible chemical bonds in the vulcanization process are difficult to recycle, resulting in a serious waste of resources. Therefore, it is important to prepare a kind of reprocessable biobased elastomers. Using furfuryl methacrylate (FMA) as the modified monomer, poly(dibutyl itaconate-myrcene-furfuryl methacrylate) (PDBIMFA) was synthesized by high-temperature emulsion polymerization successfully. The structure and compositions of PDBIMFA were characterized by Fourier transform infrared and 1H NMR, and the effects of different FMA contents on the structures and properties of PDBIMFA were systematically studied. Based on the Diels-Alder reaction, bismaleimide (BMI) and carbon black (CB) were introduced into PDBIMFA as cross-linking agents and reinforcing fillers, respectively, by the melt blending method, and PDBIMFA-BMI elastomer materials and CB/PDBIMFA-BMI elastomer composites with thermo-reversible cross-linking characteristics were prepared. The effects of the ratio of FMA and BMI on the mechanical properties of PDBIMFA-BMI were studied. PDBIMFA-BMI and CB/PDBIMFA-BMI were reprocessed twice, and the recovery rate of tensile strength was both more than 90%. The addition of CB was found to play a reinforcing role in the elastomer and with the introduction of the amount of CB, the reprocessability of composite remained at a good level. It is hoped that this research will provide a new strategy for the sustainable development of bio-based elastomer materials.

Self-Healing Superwetting Surfaces, Their Fabrications, and Properties

The research on superwetting surfaces with a self-healing function against various damages has progressed rapidly in the recent decade. They are expected to be an effective approach to increasing the durability and application robustness of superwetting materials. Various methods and material systems have been developed to prepare self-healing superwetting surfaces, some of which mimic natural superwetting surfaces. However, they still face challenges, such as being workable only for specific damages, external stimulation to trigger the healing process, and poor self-healing ability in the water, marine, or biological systems. There is a lack of fundamental understanding as well. This article comprehensively reviews self-healing superwetting surfaces, including their fabrication strategies, essential rules for materials design, and self-healing properties. Self-healing triggered by different external stimuli is summarized. The potential applications of self-healing superwetting surfaces are highlighted. This article consists of four main sections: (1) the functional surfaces with various superwetting properties, (2) natural self-healing superwetting surfaces (i.e., plants, insects, and creatures) and their healing mechanism, (3) recent research development in various self-healing superwetting surfaces, their preparation, wetting properties in the air or liquid media, and healing mechanism, and (4) the prospects including existing challenges, our views and potential solutions to the challenges, and future research directions.

Self-Healing Silsesquioxane-Based Materials

This review is devoted to self-healing materials (SHM) containing polyhedral oligomeric silsesquioxanes (POSS) as building blocks. The synthetic approach can vary depending on the role POSS are expected to play in a given system. POSS (especially double-decker silsesquioxanes) can be grafted in side chains of a polymer backbone or used as segments of the main chain. Appropriate functionalization allows the formation of dynamic bonds with POSS molecules and makes them an active component of SHM, both as crosslinking agents and as factors that enhance the dynamics of macromolecules in the polymer matrix. The latter effect can be achieved by reversible release of bulky POSS cages or by the formation of separated inclusions in the polymer matrix through hydrophobic interactions and POSS aggregation. The unique properties of POSS-based self-healing systems make them interesting and versatile materials for various applications (e.g., repairable coatings, sealants, sensors, soft materials for tissue engineering, drug delivery, and wound healing).