Fabrication And Properties Of The Carbon Fiber And Nano-particle Reinforced Thermolplastic Superhydrophobic Composites

Superhydrophobicity is defined as water contact angle above 150°and sliding angle below 10°.Chemical components and micro-nano structure play a pivotal role in fabricating superhydrophobic surfaces.Also,multi-functional superhrdrophobic materials,such as a combination of robustness,conductivity,superolephilicity with superhydrophobicity,can be more practical in industrial applications.In this dissertation,polyvinylidene fluoride?PVDF?/polymethyl methacrylate?PMMA?/nano ceria particles?CeO₂?superhydrophobic composite coating and carbon fiber?CF?fabrics reinforced PVDF/CeO₂ superhydrophobic nanocomposites are fabricated with drop-casting method and molding method,respectively.Furthermore,recyclability of the thermoplastic carbon fiber reinforced polymers?CFRPs?was also carefully investigated,and three different methods were employed to fabricate recycled CFRPs,which still exhibit good superhydrophobicity and mechanical property.In the first place,suspension system was prepared by blending CeO₂ nanoparticles,PVDF/PMMA mixed resin and solution together with different mass radios.And drop-casting method was applied to fabricate superhydrophobic coating on the composite substrate.The best formula was selected through testing the water contact angles of each coatings.According to the research WCA values reach the peak?152°?when the mass radios between solution,CeO₂ and mixtured resin is 60:27.5:12.5,simultaneously,mass radio between PVDF and PMMA is 6:4.Furthermore,chopped carbon fiber and carbon fiber powder were utilized to enhance the wear resistance of the coating.The results indicate that chopped carbon fiber can greatly improve the wear resistance of the coating without affecting superhydrophobicity.As for coating with carbon fiber powder,a small quality?less than 300mg?does not influence the hydrophobicity,however,an addition beyond 300mg would decrease WCA value of the coating.Also,carbon fiber powder is conducive to the wear resistance.According to the idea of an integration of structure and function,CF/CeO₂/PVDF thermoplastic superhydrophobic nanocomposite was prepared with molding method.When the mass fraction of ceria particles is 55%,the sample shows superhydrophobicity with WCA value of 152°and WSA value of 3°.However,only a small area of the surface shows superhydrophobicity,thus two different solutions were used to improve the nanocomposites.Firstly,stearic acid was utilized to modify CeO₂ particles.Owing to the modified particle,the nanocomposite shows superhydrophobicity in a large scale.Also,mechanical property increased with the increase of resin on the base of the modified nanocomposites,but hydrophoboicity decreased at the same time.Secondly,carbon black?CB?was added,and CB/CF/PVDF/CeO₂ nanocomposite was prepared.Benefiting from the adding of CB,both wettability and conductivity were improved,And the nanocomposites show superolephilicity and improved wear resistance.However,mechanical property dipped because the addition of CB could lower bonding strength between layers.Thus,the failure of the CB/CeO₂/PVDF/CF composites occurs via interfacial failure without breakage of the CF cloths and felt.Finally,three different methods were utilized to fabricate recycled CFRPs by molding process with scrape materials of the composites with the idea of recycling superhydrophobic materials,which still exhibited superhydrophobicity and good mechanical property.