POSS-capped Polymer Telchlics:Synthesis,Morphologies And Shape Memory Properties

Organic-inorganic hybrid polymer materials have wide application prospects because of possessing both the advantages of organic and inorganic materials.However,the dispersibility of the inorganic components in the materials obtained by the blending method is poor due to the different solubility of the organic and inorganic components in the hybrid materials that will affect the properties of the materials.Therefore,it is the key that to find suitable solution to prepare organic-inorganic hybrid materials at the nanoscale.In this paper,a series of POSS capped polymers and POSS – Capping telechelic polymers were prepared by chemical synthesis methods such as RAFT active polymerization,click chemistry,ring-opening polymerization(ROP).Organic hybrid composites with different structures and properties were synthesized.The structural properties of these POSS-containing hybrid composites were studied by measurements of various characterization methods.In addition,we have prepared rectangular samples to study the polymer shape memory performance with introducing POSS.The main contents are as follows:(1)Synthesis of POSS-capped poly(5-acetamidopentyl acrylate)s.First,the 5-acetamidopentyl acrylate monomer wassynthesised by an amidation reaction.In this reaction,a POSS-containing chain transfer agent is prepared by esterification of 3-Hydroxylheptaphenyl POSS with sulfer.Then Poly(5-acetamidopentyl acrylate)shape memory materials with different molecular were prepared via RAFT reaction.We have studied the microphase separation structure and self-assembled structure of POSS in polymers by transmission electron microscopy(TEM),small-angle X-ray scattering(SAXS)and dynamic laser scattering(DLS).The effects of the introduction of cage-type POSS on the surface hydrophobicity and thermal stability of organic-inorganic hybrid PAA were investigated by atomic force microscopy(AFM),contact angle measurement and thermogravimetric analysis(TGA).The glass transition temperature,creep properties and shape recovery properties of POSS-capped PAA were analyzed by dynamic mechanical analysis(DMTA).In addition,the shape recovery process of the polymer was recorded with a digital camera by preparing a spline of a certain size.(2)Synthesis of POSS-PEO-POSS and POSS-PCL-POSS telechelic polymersWe mainly use click chemistry to synthesis POSS-containing telechelic polymers.Preparing different molecular PEO and PCL and then the POSS was introduced into the polymer through the "click" reaction in order to synthesis POSS-containing telechelic polymer.The effects of introducing of POSS on thermal stability and crystallinity of PEO and PCL were investigated by thermogravimetric analysis(TGA)and differential scanning calorimetry(DSC).Due to the hydrophilicity of PEO,the size and morphology of telechelic polymer self-assembled micelles were observed by dynamic laser scattering(DLS)and transmission electron microscopy(TEM).Based on the melting temperature of the telechelic polymer described above,the shape memory properties of the two polymers having physical cross-linking network structure were investigated.(3)POSS-terminated poly(butyl acrylate-ran-UPA)telechelic polymerIn this work,POSS-terminated poly(butyl-ran-butyl)-ran-UPA)telechelic polymers were prepared by "monomer-insertion" synthesis.First,we need to prepare the UPA monomer.The most important is the preparation of the POSS containing chain transfer agent.Poly(butyl acrylate-ran-UPA)telechelic polymers with different molecular weights were prepared by RAFT polymerization.The molecular weight of the polymer was characterized by gel permeation chromatography(GPC).The effect of the addition of POSS on the glass transition temperature was analyzed by differential scanning calorimetry(DSC).The structure of the polymer was observed by transmission electron microscopy(TEM).