Study On Synthesis Of Rosin Modified Waterborne Polyurethane

In this paper, the waterborne polyurethane was modified by rosin. The relationship between structure and properties of rosin modified waterborne polyurethanes was studied. It was found that the addition of rosin ring structure could increase gloss, hardness, heat resistance and water resistance of waterborne polyurethane.Acrylpimaric acid was separated and purified from acrylic modified rosin by means of sodium salt method. Effects of the sort of alkali, the amount of alkali, water and sodium chloride on the yield and the purity of acrylpimaric acid were investigated. The structure of acrylpimaric acid was characterized by IR, ~1HNMR and single crystal X-ray diffraction.Maleopimaric acid was synthesized under microwave irradiation using gum rosin of pinus massoniana and maleic anhydride. Effects of the reaction time, microwave power, the amount of acetic acid, and molar ratio of abietic-type resin acids to maleic anhydride were investigated. The optimum synthetic conditions were obtained based on the orthogonal experiment results: the reaction time was 28 min; microwave power 120W, the dosage of acetic acid 29% of the totsl mass of rosin and maleic anhydride, molar ratio of abietic-type resin acids to maleic anhydride 1.1:1 (mol/mol), the yield of maleopimaric acid was 70.3 %, m.p. 226-227℃, acid value 415.4 mg/g. The structure of maleopimaric acid was characterized by IR, ~1HNMR and single crystal X-ray diffraction.Acrylpimaric acid polyester polyols (AAPP) were prepared from Acrylpimaric acid by the process of multistep feeding of diols. Maleopimaric acid polyester polyols were prepared from maleopimaric acid and adipic acid. The structure of acrylpimaric acid polyester polyols and maleopimaric acid modified polyester polyols was characterized by FI-IR spectra.Rosin modified waterborne polyurethanes were maded from acrylpimaric acid polyester polyols and maleopimaric acid modified polyester polyols. The properties such as specular gloss, pendulum hardness, impact strength, adhesion flexibility and water-resistance were investigated respectively. The results indicated that the addition of rosin ring structure could increase gloss and hardness, heat resistance and water resistance of waterbome polyurethane. When the addition level of acrylpimaric acid polyester polyols is 40% (relative to the total weight of AAPP and polyether glycol), acrylpimaric acid-based waterbome polyurethane has good performances with specular gloss of 131.6, pendulum hardness of 0.70, impact resistance of 80 kg·cm, 5% weight loss temperatures of adhesion of 1 grade, flexibility of 1 mm. The products were characterized by FI-IR spectra and TGA.