| The refined lacquer, waterborne dispersion of raw lacquer and urushiol could be obtained by physical modification and chemical modification,. Polymer materials with high performance were prepared by blending them with terpene-based waterborne polyurethane. The main topics of this research are as follows:(1) the stability and rheological property of blended emulsion.(2) the morphology, mechanical properties and thermal properties of the blended films.(3) the relationship between the performance of composite polymer and material ratio.(4) the conditions and mechanisms of the film formation.1. Raw lacquer combined terpene-based waterborne polyurethane and its film propertiesBlended films were prepared by blending refined lacquer with terpene-based waterborne polyurethane in different proportions. The results showed that the stability of blended system was improved with refining natural lacquer. In the blended system of terpene-based waterborne polyurethane, the blended films were smooth and dense when the content of the lacquer was ≤ 20% and it had good compatibility. With the content of lacquer increasing, the thermal stability, gloss, pencil hardness, tensile strength and water resistance of the blended films increased. In the blended system of refined lacquer as based resin, the formation time could be shortened with the content of terpene-based waterborne polyurethane increasing. The gloss of the film was improved because of the microstructure changing. Terpene-based waterborne polyurethane had a toughening effect on lacquer, so that the flexibility, adhesion and impact strength of the blended film were improved significantly.2. Waterborne dispersion of raw lacquer(WRL) combined terpene-based waterborne polyurethane and its formation mechanismsWaterborne dispersion of raw lacquer(WRL) was blended with Terpene-based waterborne polyurethane in different proportions which was prepared by compound emulsifier, and then the films were formed. The emulsifying effect could be improved by compound emulsifier of OP-10/SDS/PVA and the optimum mass ratio was 7:3:10. The dispersion had a good stabilitywith particle size ≤ 800 nm when the dosage of composite emulsifier reached 10% by weight. WRL/terpene-based waterborne polyurethane blended system had a good centrifugal stability, and its apparent viscosity was decreased with the increasing of shear rate, which was pseudoplastic fluid. With the content of WRL increasing, the formation time of the blended film was prolonged and pencil hardness was improved, but the flexibility and adhesion were reduced.Temperature had the most obvious effect on the formation time. With temperature and humidity increasing, the tensile strength and the elongation at the break of the film were decreased. The surface drying process was mainly physical process, accompanied by water evaporation and particle coalescence. Temperature, humidity and the solids content influenced the surface drying time by affecting the evaporation rate of water. Hard drying process of the film was based on chemical cross-linking and laccase catalytic. When the temperature was lower, the effect of film formation by laccase catalytic was more significant. Meanwhile, formation was based on chemical reactions under high temperature conditions. Urethane group was reacted completely with hydroxy group and active hydrogen after heated 5 h at 70 ℃. For unsaturated double bonds in the side chain of raw lacquer, the temperature above 130 ℃ was conducive to oxidation and polymerization, then cross was linked into integrated network structure.3. The preparation of terpene-based waterborne polyurethane modified by urushiol and its propertiesUrushiol diglycidyl ether(UDE) was synthesized from epichlorohydrin(ECH) and urushiol(Ur) which can be obtained by ethanol extraction. A series of terpene-based polyols emulsion modified by urushiol were prepared from terpinene-maleic ester type epoxy resin(TME)and urushiol diglycidyl ether(UDE). The waterborne polyurethane films were obtained by mixing the terpene-based polyols modified by urushiol with polyisoeyanate(D80). The results showed that the mass ratio of TME and UDE had some effect on the emulsion stability, viscosity and particle size distribution. The emulsion property of terpene-based polyols modified by urushiol was the best when the mass ratio of TME to UDE was 1:1. It was found that the surface hydrophobicity, water resistance and thermal stability of the films modified by urushiol were improved with the mass ratio of UDE increasing, but the tensile strength of the film was reduced. By increasing the content of TMP and n(-NCO)/n(-OH), the degree of cross linking can be increased to improve the water resistance of the film, and the glass transition temperature and the tensile strength of the film can also be increased. The optimum content of TMP was 12%~14%, n(-NCO)/n(-OH) was 1.2 ~ 1.4. |
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