Preparation and Mechanical Properties of UV⁃Assisted Filament Winding Glass Fiber Reinforced Polymer⁃Matrix Composite

This paper studied the preparation and mechanical properties of glass fiber reinforced polymer-matrix composite rings prepared by filament winding assisted by ultraviolet(UV)curing.A ray-tracing method was used to calculate the penetration ability of UV light in the resin casting,and then a typical composite ring with dual⁃curing characteristics was prepared by UV-assisted curing.The effects of winding speed and thermal initiator concentration on the distribution of fiber fraction and mechanical properties were studied.Microscopic morphology was used for the observation of the differences in fiber volume fraction.Mechanical properties tests and scanning electron micrographs were performed to investigate the failure and damage mechanisms of the composite ring samples.The ray tracing results indicate that the UV light can pass through a single yarn thickness and the energy transmitted is sufficient to cure the back side quickly.The experimental results show that the mechanical properties of the composite ring prepared in this paper are comparable to those of the heat-cured samples,which is sufficient to meet the requirements of the flywheel.

Carbon-coated hybrid crystals with fast electrochemical reaction kinetics for ultra-stable and high-load sodium-ion batteries

Owing to its high theoretical capacity and low cost,Sn has attracted significant attention in sodium-ion batteries.However,the slow kinetics of electrochemical reactions and the rapid decay of capacity resulting from drastic changes in the volume of Sn,as well as persistent side reactions between Sn and the organic electrolyte during the(de)sodium process,have limited its commercialization.To improve the electrochemical performance of Sn-based materials,the bottom-up method is normally used to prepare carbon-coated nanoparticles.However,its complex preparation processes and harsh conditions make it unsuitable for practical applications.Herein,a carbon-coated hybrid crystal composite(Sn/SnO_(x)@C)was prepared using an up-bottom method with commercial Sn/SnO nanoparticles.Various effects accelerate the electrochemical kinetics and inhibit the coarsening of Sn crystals.The Sn/SnO_(x)@C composite electrode exhibited capacity retention of 80.7%even after approximately 1000 cycles(360.4 mAh·g^(−1)) at a current density of 1 A·g^(−1).The high-load Na_(3)V_(2)(PO4)3||Sn/SnO_(x)@C full cell presents a capacity retention rate of 91.7%after 150 cycles at the current density of 0.5 A·g^(−1).This work may significantly accelerate the commercialization of the Sn/SnO_(x)@C composite in sodium-ion batteries with high energy density.

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.