Preparation And Properties Of Organic Silicon Modified Castor Oil-based Polyurethane

With the increasingly serious of energy crisis, global warming and the increase of people’s environmental consciousness, research on renewable resources instead of chemical raw materials for the preparation of environment friendly has become the focus of attention. Vegetable oil instead of chemical raw materials which is cheap and renewable and has a broad market, is a kind of rich resources of raw materials. Vegetable oil based polyurethane has excellent weather resistance, high elasticity, high gloss and solvent resistance and other advantages, but the high temperature resistance and chemical resistance is poor. Silicone material has flexibility, aging resistance, high and low temperature resistance and surface energy and other advantages, and can make up for the shortcomings of vegetable oil based polyurethane. Silicone modified polyurethane has wear resistance, corrosion resistance and other advantages of polyurethane and silicone material has the advantages of high temperature resistance, water resistance, aging resistance and etc.. Although researchers have done a lot of research on silicone modified vegetable oil based polyurethane, but via thiol-ene click reaction introducing silicon into vegetable oil polyurethane was rarely reported. Based on the above research background, the research work carried out the following aspects:1. Castor oil and 3-mercapto propyl siloxane as starting material, which via the thiol-ene click reaction are for the preparation of silicon containing castor oil based polyols (MSCO), and then with isophorone diisocyanate (IPDI) polymerization for preparation of silicone modified castor oil based solvent type polyurethane. The influence factors in monomers synthesis process are discussed and selected the optimal experimental condition; Infrared Spectroscopy (FT-IR) and nuclear magnetic resonance (NMR) were used to character the structure of monomers; Using tensile testing machine, thermo gravimetric analyzer (TGA), differential scanning calorimetry (DSC) and scanning electron microscope (SEM) to tested the mechanical properties, thermodynamic properties and surface morphology of the coatings. The experimental results show that:the introduction of silicone will make the surface of polyurethane become more roughness, and appear some microphase separation; siloxane in polymer materials can be used as nano additive, which make the cross-linking density, thermal stability and mechanical properties of plant oil based polyurethane increases; Low surface energy compounds of organic silicon into polyurethane makes its water resistance improved significantly.2. Castor oil and 3-mercapto propionic acid as starting material, which via the thiol-ene click reaction for the preparation of castor oil based carboxylic acid hydrophilic chain extender, and then use MSCO as polyols, react with IPDI to prepare silicone modified castor oil based waterborne polyurethane. FT-IR and NMR were used to character the structure of monomers; Using transmission electron microscopy (TEM), tensile testing machine, TGA, DSC and SEM to tested emulsion morphology and the mechanical properties, thermodynamic properties and surface morphology of the coatings. Experimental results show that siloxane in the main chain of polymer can polymerization and enrich together in water system, and produce SiO2 nanoparticles. The particle can be used as nano reinforcing agent to improve vegetable oil based waterborne polyurethane thermal properties and mechanical properties; The enrichment of SiO2 will not only make the hybrid films has a certain micro phase separation, but also can make the ultraviolet light refraction through the film, which makes the transmission of waterborne polyurethane film rate is greatly reduced.3.3-Mercapto propyl siloxane is hydrolyzed under acid condition to prepare POSS-SH, and then react with G04 via thiol-ene click reaction to synthesis a series of fluorine silicon double functionalized POSS. At last, functionalized POSS react with double bond terminated castor oil based polyurethane under UV light irradiation to prepare UV curing coatings. FT-IR, NMR and X ray photoelectron spectroscopy(XPS) were used to character the structure of monomers; Using tensile testing machine, dynamic mechanical thermal analyzer(DMA), TGA, DSC and SEM to tested emulsion morphology and the mechanical properties, thermodynamic properties and surface morphology of the coatings. The UV curing coatings has a convergent surface and good compatibility. Low surface energy compounds of fluorine and silicon into polymer materials will greatly reduce the surface energy, which made the contact angle increased from55° to 92.9°, the elongation at break increased from 58.1% to 390.6%, the tensile strength increased from 0.81MPa to 1.43MPa.