The Synthesis Of Functionalized POSS And Its Application Research In UV-curing Coating

Polyhedral oligomeric silsesquioxanes(POSS)is a kind of high-performance organic/inorganic nano materials.The special three-dimensional space structure gives it good mechanical properties,biocompatibility,low dielectric property and heat resistance.It can be compounded with organic phase or polymer matrix by copolymerization,grafting or blending to obtain different functional composites.The synthesis of POSS with different functionalities in the preparation of functional composites has always been one of the frontier hot topics in the development of composites.POSS has nano scale organic/inorganic hybrid framework.The cage type inorganic Si-O-Si core endows POSS with some unique physical and chemical properties and the multiple reaction sites that can be further chemically modified with organic groups to prepare multifunctional composites and improve the properties such as hydrophobicity,chemical durability,mechanical and thermal stability.Different from the traditional methods,the thiol-ene click chemistry reaction is more convenient and efficient,which was the new method of organic synthesis,material design and rapid preparation and provided the possibility for the rapid synthesis of POSS/polymer composites.Therefore,this paper starts from the preparation of functional POSS with different structures.After modification,a variety of composite materials are prepared by photo click chemical method,including fluorine functionalized POSS based superhydrophobic materials with good oil-water separation performance,the fluorine free superhydrophobic sponge with environmental protection and harsh environment resistance prepared by a simple one-step method,and the lotus leaf like superhydrophobic coatings.The preparation method,mechanism and mechanical stability,hydrophobicity,oil-water separation performance of these materials are also discussed.This paper will start from the following four chapters:(1)Preparation of POSS with T-type and MQ-type structures.Using(3-Mercaptopropyl)trimethoxysilane as the raw material and hydrochloric acid as the catalyst,the condensation reaction was carried out in methanol to prepare the POSS(SH-POSS)with mercapto groups successfully which defined as the T-shaped structure.Using tetraethyl orthosilicate(TEOS)as raw material,etramethylammonium hydroxide pentahydrate as the catalyst,the hydrolysis and condensation reaction was carried out in water and methanol to prepare octahedral polysilsesquioxane ammonium salt.Then,the substitution reaction with chlorodimethylvinylsilane was carried out to prepare the polyhedral oligomeric silsesquioxanes(Vi-POSS)with vinyl groups,which defined as the MQ-shaped structure.(2)One-step preparation of fluorine-functionalized superhydrophobic sponge.The SH-POSS and 1H,1H,2H-perfluoro-1-hexene of different molar ratios were subjected to the thiol-ene click chemistry reaction under 365nm ultraviolet light irradiation.The obtained fluorinated thiol-functionalized POSS(F-POSS-SH)was grafted onto melamine foam(MF)surface through the mercapto amino reaction,to prepare fluorinated functional 3D structure superhydrophobic sponge(F-POSS-SH@MF)with different surface morphology and hydrophobicity.The test results of Fourier transform infrared(FTIR),High-resolution X-ray photoelectron spectra(XPS)and scanning electron microscope(SEM)proved that F-POSS-SH has been successfully grafted to the surface of MF.The composite materials was tested for wettability,separation ability,and mechanical stability.The results proved that it has good superhydrophobicity,superoleophilicity and mechanical properties and can separate oil-water mixtures quickly and efficiently.(3)One-step preparation of fluorine-free environment-friendly superhydrophobic sponge(SH@POSS-MF).The SH@POSS-MF was prepared by one-step process of grafting Vi-POSS and pentaerythritol tetra(3-mercaptopropionate)onto the surface of MF.Part of the sulfhydryl group on pentaerythritol tetra(3-mercaptopropionate)reacted with the amino group on the surface of MF by Michael addition reaction,and the rest of the sulfhydryl group reacted with the double bond on Vi-POSS by thiol-ene click chemistry reaction.The Vi-POSS grafted onto the surface of MF,increasing the roughness of MF surface and reducing the surface energy,making the MF superhydrophobicity,so that the materials can be used for oil-water separation.It has good adsorption capacity for organic solvents with different densities.In addition,the SH@POSS-MF still has stable superhydrophobicity after soaking by-196?liquid nitrogen,250?muffle furnace for heating 2h and p H=1 to 14.Therefore,the SH@POSS-MF can be used for oil-water separation under harsh conditions.(4)To prepared the POSS based superhydrophobic coating on the 2D planar structure.Grafted different concentrations of?-mercaptopropyltriethoxysilane(MPTES)onto Vi-POSS through the thiol-ene click chemistry reaction to obtain the functionalized POSS(OEt-POSS),then combine it with the mixture of methacryloxy propyl trimethoxyl silane(MPS)modified Si O₂(MPS@Si O₂),dodecafluoroheptyl methacrylate(12FMA)and methyl methacrylate(MMA)and sprayed on the glass slide.Put it under 365nm ultraviolet light to obtain superhydrophobic coating.Compared with the FTIR and XPS of uncoated glass,it is proved that all components have been grafted on the surface.The superhydrophobic coating still maintained superhydrophobicity under 10 falling sand-heating cycles and different p H conditions.In addition,through the SEM,the effect of different concentrations of MPTES reacted with Vi-POSS on the surface morphology of the coating was explored.