Effect of three-dimensional to one-dimensional orientation of cellulose nanofiber sizing agents on carbon fibers under magnetic and electric fields on composite material properties.

Nanoparticle-containing sizing agents are essential for the overall performance of high-quality carbon fiber (CF) composites. However, the uneven dispersion of nanoparticles often leads to agglomeration on the surface of CF after sizing, consequently diminishing the material properties. In this study, the properties of cellulose nanofibers (CNFs) that can respond to magnetic and electric fields were utilized to achieve three-dimensional to one-dimensional orientations in CFs containing sizing agents. Cobalt ferrite (CoFe2O4) was utilized to enhance the response of CNFs to a magnetic field, and subsequently, it was combined with an electric field to attain a higher degree of orientation. The occurrence of nanoparticle agglomeration is diminished on CF surface, while establishing a structured network. The flexural strength and thermal conductivity of CF composites treated with CoFe2O4 self-assembled CNF sizing agent exhibit an increase of 54.23 % and 57.5 %, respectively, compared to those of desized CF composites, when subjected to magnetic and electric fields. Consequently, the approach can depolymerize the nano-fillers within the sizing agent and orient it into the carbon fiber under the influence of magnetic and electric fields, effectively improving the mechanical properties and thermal conductivity of the composite material.

Preparation of quaternized N-halamine modified graphene oxide based antibacterial hydrogel and wound healing of bacterial infection.

In clinical practice, the wound on the surface of the skin is prone to bacterial infection, for which healing of infected wounds has always been a tremendous challenge for clinics and research institutions. We developed a multifunctional bactericidal, recyclable, and slow-release graphene oxide-based hydrogel for bacterial wound healing and real-time monitoring of bacterial infection in this study. At the same time, the material has a sensing function, which can be used in the connection between the injured skin and the continuous detection equipment. QNGH (quaternarized N-halamine-grafted GO hydrogel) is manufactured by hydrogen bonding between quaternized N-halamine-modified graphene oxide and polyvinyl alcohol (PVA). The results show that in the mouse model of full-thickness skin repair, the hydrogel can continuously release germicidal ions and recyclability, promoting wound healing and contraction. Further, the graphene oxide-based hydrogel has excellent strain sensing performance. It detects the bending and stretching movements of different parts of the human body quickly, stably, and sensitively to show an excellent real-time monitoring performance of human motion. The sensing function of the hydrogel further broadens its application field. Therefore, this hydrogel material is expected to be a candidate material for sensing devices at the wound.

Fabrication of microcapsule-type composites with the capability of underwater self-healing and damage visualization.

Inspired by biology, underwater self-healing polymer composites with damage-healing visible agents were successfully designed and prepared. The healing agents, same as epoxy resin matrices, were encapsulated and embedded into a matrix that contained fluorescent latent curing agents. The results of investigation on healing properties revealed that the fluorescent latent curing agents and the microcapsules in the matrix play two roles. First, the matrix could be self-healed via a crosslinking reaction between the amine group and epoxy resin, in which the amine group could be released from the fluorescent latent curing agents (FLCAs) after exposure to water. Second, the fluorescent dyes released under water could indicate the scratches and healing area visually. Embedding 15 mass% microcapsules and 6 mass% FLCAs in self-healing materials yielded a healing efficiency of 85.6% and the most efficient fluorescence detection. Self-healing materials can be repaired underwater and they show the location of damage, which is of great significance in applications such as water conservation engineering, environmental treatment engineering, ship engineering and ocean engineering.