Structure And Properties Of Micro/Nanostructured Epoxy Thermosets

In this work,a series of ABA amphiphilic copolymers were synthesized via the combination of ring-open polymerization and hydrosilylation reaction,and a new type of epoxy monomers was synthesize.There products were used for the modification of epoxy thermosets,a new type of epoxy microspheres and a series of nanostructured epoxy thermosets were successfully prepared.The micro/nanostructures and formation mechanisms of the crosslinked polymers containing block copolymers were characterized by means of scanning electron microscope(SEM),transmission electron microscopy(TEM)and small-angle X-ray scattering(SAXS).Furthermore,the properties of the micro/nanostructured materials were investigated,and relationship between structure and properties were also investigated.The main results were summarized as follows:1.A novel epoxy monomer,diglycidyl ether of tetraphenylethene(DGETPE)was synthesized and then it was incorporated into a commercial epoxy(viz.diglycidyl ether of bisphenol A)to obtain the epoxy microspheres with the size of 1-3 mm via phase-inverted reaction-induced phase separation approach.It was found that the epoxy microspheres were luminescent under UV lightradiation.The surfaces of the photoluminescent epoxy microspheres were further functionalized with poly(N-vinylpyrrolidone)(PVPy)with a grafting-from methodology via reversible addition-fragmentation chain transfer/macromolecular design via the interchange of xanthate(RAFT/MADIX)process.The PVPy-grafted epoxy microspheres can be welldispersed into the aqueous solutions.The morphologies and photophysical properties of the epoxymicrospheres were investigated by means of scanning electron microscopy,UV-vis and fluorescence spectroscopy.2.Poly(?-caprolactone)-block-(polybutadiene-graft-POSS)-block-poly(?-caprolactone)triblock copolymer was successfully synthesized viaring-opening polymerization of ?-caprolactonewith hydroxyl-terminated polybutadiene as the initiator,then hydrosilylation reaction of 3-hydroheptaphenyl POSS.The novel organic-inorganic amphiphile was used to incorporate into epoxy resin to prepare the nanostructured thermosets,and the nanostructures of thermosets were investigated by means of transmission electron microscopy(TEM),small-angle X-ray scattering(SAXS)and dynamic mechanical thermal analysis(DMTA).Surface properties was researched by means of static contact angle measurements and X-ray photoelectronspectroscopy(XPS).3.Poly(?-caprolactone)-block-polybutadiene-block-poly(?-caprolactone)(PCL-b-PB-b-PCL)and poly(?-caprolactone)-block-polybutadiene(pentamethyldisiloxane)-block-poly(?-caprolactone)[PCL-b-PB(Si)-b-PCL],these two structurally similar triblock copolymerswere synthesized via ROP and hydrosilation reaction and possessed the identical compositions and close molecular weights.These two type of block copolymers wereincorporated into epoxy to obtain the nanostructured thermosets.TEM microphotos of these two nanostructured thermosets showed that the introduction of Silicon-containing component changed the nanostructure in the epoxy resin and further explore the difference between the properties of two materials.