Study On Preparation And Properties Of Methyl-esterification Tung Oil-Modified Water Polyurethane Emulsion

Water-borne polyurethane(WPU) is widely used in adhesive and coating areas, asits excellent abrasion resistance, flexibleness and adhesive. However, single Water-bor-ne polyurethane is existing some poor performance, such as the lack of bindingperformance, drying speed, water resistance shortage, so it set bounds to its furtherapplication in many areas. The methylester of tung oil (METO) possess excellentproperities dues to its long unsaturated fat chain. Copolymer of METO and WPU bychemical modifcation combining their advantages for improving the properties ofwater-borne polyurethane is a effective method.The development, modification and the good performance of single water-bornepolyurethane as well as the modification of WPU by plant oil was reviewed. Toimprove the application properties of the one-component WPU, the methylester of tungoil was used to chemically modify the properties of single WPU in the present thesis.The result shows the water-and polar solvent-resistance and films formation propertiesof WPU has been improved by METO modification and the shortages of low bondingstrength, poor heat and water resistance have been overcome.The polyether-type WPU was prepared based on self-emulsified process; then aseries of METO modified MWPU were prepared by chain extending. The preparedWPU and MWPU were characterized and analyzed by Fourier Transform InfraredSpectrometer (FT-IR), Scanning electronic Microscope (SEM), Dynamic Light Scatter-ing (DLS) and themogravimetric analysis (TG). It shows that the stability of chemicalmodified polyurethane was better than that of the blending modification. The effects ofR value (-nNCO/-nOH), dimethylol propionic acid (DMPA) and METO on the propert-ies of MWPU were researched and analysised. The analysis result shows that DMPA isthe main factor on the stability of MWPU; the particle sizes were highly influenced byR value; the properties of bond strength, heat and water resistance and thermostabilitywere highly improved by METO. While DMPA content is4.3%, R value is1.2, andMETO is6%, the optimal properties of the MWPU will be achived.To study the effect of METO on WPU and optimize the properties of the modifiedemulsions, the process for preparing the MWPU was adjusted on the basis of theprocess for polyether-type WPU.1,4-butandiol (BDO) was used as extender in theWPU preparation. The result indicates that the mechanical properties of WPU extendedby BDO (BWPU) are improved but the water and solvent-resistance are lowered. Based on BWPU, METO was used to modify BWPU bycopolymerized chain extension. Then MBWPU were characterized by FT-IR, SEM andTG, and the viscosity, cross-linking degree and mechanical property were also tested.The result shows that while METO content is4.8%, the properties of MBWPU are the optimal, whose water absorption is11.5%, acetone absorption13.2%, peel strength19.3N/cm, adhesive force0order, elongation at break332%, tensile strength2.2MPa,5%and50%mass-loss temperature is about259.1℃and373.8℃separately..Then, compared with the properties of similar study of aqueous polyurethane, theaqueous polyurethane prepared during this study can be used as wood adhesive or resinraw materials.