Influence of Surface State on Moisture Sensitivity of Carbon Fiber and Its Composite Interfacial Properties

The influence of surface state on the moisture sensitivity of carbon fiber was analyzed by applying a T800 grade carbon fiber with five different surface conditions,namely,with and without surface oxidation,in the presence or absence of sizing agent.The interfacial properties of their composites in the presence of two epoxy matrices（respectively EP07 and EP10） were also characterized by micro-droplet tests.The overall results show that both oxidized and sizing-coated fibers have higher moisture equilibrium content than that of the pristine unsurface-treated fiber,due to higher amount of activated carbon groups.After moisture absorption of the carbon fibers,almost all the fiber/epoxy systems show decrease in the interfacial shear strength and the unsurface-treated fiber system exhibits the largest decline.Moreover,both interfacial shear strength and interlaminar shear strength of carbon fiber/EP10 composite demonstrate better water resistance performance than that of the carbon fiber/EP07 composite,consistent with DSC results of the two resins.

Robust UV/moisture dual curable PDMS-microcapsule-silica functional material for self-healing,antifouling,and antibacterial applications

Polydimethylsiloxane containing methacryloyloxy and methoxy silane groups(MAPDMS)-microcapsule-SiO_(2)(MPMS)functional materials were prepared by constructing micro-nano hierarchical structures on the surface of MAPDMS matrix.Herein,MAPDMS@1,1-stilbene-modified hydrolyzed polyglycidyl methacrylate/graphene oxide/dimethyloctadecyl[3-(trimethoxysilyl)propyl]ammonium chloride(MAPDMS@PGMA_(m)/GO/QC18)self-healing microcapsules with compact multi-shell structure were synthesized and combined with nano-SiO_(2)to construct the hierarchical structures.Furthermore,ultraviolet(UV)/moisture dual curing mode was introduced into deep curing reaction and efficient self-healing reaction of the MPMS.The results show that the introduction of UV/moisture dual curing mode and micro-nano hierarchical structure gives MPMS functional materials excellent mechanical properties,antifouling properties,self-healing properties,antibacterial properties.The shear strength and tensile strength of MPMS increase from 3.32 and 4.26 MPa of MAPDMS to 3.81 and 5.06 MPa,respectively.Its static contact angle increases from 115.9°of MAPDMS to 156.5°,its slide angle decreases from 68.5°of MAPDMS to 7.8°,respectively.The antifouling performance of MPMS against seawater,soy sauce,juice,coffee,protein,other contaminants is effectively improved compared with MAPDMS matrix.At the same time,the tensile strength and elongation at break of MPMS after healing reach 98.22%and 96.57%of those in original state,respectively.In addition,the antibacterial rates of MPMS against Escherichia coli and Staphylococcus aureus reach 99.85%and 100%,respectively.The MPMS prepared in this paper is expected to be widely used in marine antifouling,pipeline network,anti-icing,microfluidics,wearable devices,medical devices,electrochemical biosensors,other fields.