Studies On Modification Of Polyurethane And Latent Curing Agent Of Epoxy Resin

Nano-silica and epoxy resin E-44were introduced into the preparation of polyurethane which was based on isophorone diisocyanate (IPDI), polycarbonate-diol (PCD), polycaprolactone (PCL) so as to improve the physical and chemical performance of the material.The modified polyurethane was characterized and compared by scanning electron microscope,X-ray diffraction, thermo gravimetric analyzing and IR.With an addition of nano-silica between0.5%and1.5%,a good dispersion of nano-silica was observed in the modified material and improvement of water absorption rate,hardness,yellowing temperature and thermal stability was obtained with the polyurethane,while no further improvement was observed with an addition of nano-silica above1.5%.Several latent curing agents for epoxyacrylic resins were synthesized from y-aminopropyltriethoxysilicane and characterized by elemental analysis,IR and ’HNMR.Water boiling resistence, water-absorption rate, yellowing temperature and hardness of epoxyacrylic resins contained3%of the above mentioned curing agents were tested. It was showed that these curing agents mantained chemically stable at room temperature while performed a relatively curing activity at120℃,remarkably improving the various properties of epoxyacrylic resins.Epoxy acrylic resins perform poorly in water resistance and corrosion resistance without the adding of curing agents, y-aminopropyltrithoxy-silane can serve as curing agent for epoxy acrylic resins but the pot life of the resins became too short with the adding of y-aminopropyltrithoxy-silane, which seriously limited its use. In this paper, novel latent curing agents for epoxy acrylic resin a-e were synthesized and characterized with’H NMR, MS, and elemental analysis in this study. Pot life of epoxy acrylic resins containing3wt.%a-e or y-aminopropyltrithoxy-silane was compared in this paper and experiment data indiacted that a-e were inactive in epoxy acrylic resin at room temperatre. Curing temperature for double compositions resin is about120℃and pot life at room temperature is longer than6monthes. The effectiveness of a-e as curing agents for epoxy acrylic resin were determined through several experiments, such as water resistance test, brine resistance test, acid resistance test, pencil hardness test, etc. DSC and FT-IR were carried out to determine the curing process of the resins. TGA was carried out to evaluate the thermostability of the resins. Finally, SEM was used to inspect the microstructure of the resins. The effectiveness of a-e for epoxy acrylic resins was compared with that of traditional amine curing agent y-aminopropyltrithoxy-silane and no inferiority in properties was observed. It was found that a-e within epoxy acrylic resins enhance the water resistance and corrosion resistance performance of the resins, as well as thermostability.