Study On Synthesis, Modification And Application Of Rosin-based Hyperbranched Polyester For UV Curing Reaction

Rosin, as one of the renewable resources in the world, is widely used in the field of coatings, inks, paper, adhesives, soap and building materials. It is also the important material of fine chemicals and new polymer materials. With the further processing and utilization research on rosin, resin acids and new polymer materials synthesis from rosin acids, have become a research focus and development trends. In this work, MPA was synthesized by Maleic anhydride and resin acid as the raw material, hyperbranched polyester was synthesized by using MPA as one monomer. The modified of hyperbranched polyester for UV curing was also studied. This work will provide a reference for the MPA as UV curing materials.First of all, with acetic acid as solvents and catalyst, MPA was synthesized by maleic acid and resin acid, which is extracted from rosin. MPA purity by GC analysis was 98.5 %.The hyperbranched polyester was synthesized by using maleopimaric acid and epichlorohydrin, with tetrabutyl ammonium bromide as catalyst and DMF as solvent. The influencing factors such as n MPA/ n ECH reaction temperature and the monomer feeding manner were discussed. The reasonsble technology condition was T=110 ℃, n MPA/ n ECH=1:2 and dropping slowly. At this conditions, hyperbranched polyester has large molecular weight, Mn=3380,Mw=7030.In the above reaction conditions, the hyperbranched polyester synthesized by using maleopimaric acid and glycidol was also studied. Due to the special structure of hyperbranched polyester, the branching degree(DB) of the hyperbranched polyesters can be calculated based on 1H NMR. Result shows that the ratio of MPA/glycidol was the major factor that influences the molecular weight and DB. Feeding manners have little influence on DB. The polymerization temperature only influences the reaction time. Among this synthesized, the range of Mn is 750~2800, and the DB ranges from 0.27 to 0.63.Acrylic acid and acryloyl chloride were used to modify the hyperbranched polyester through the reaction with hydroxyl groups. After modification, HBPE has large number of vinyl as end-group. FT-IR spectrum indicated that acryloyl chloride modified more completely than acrylic acid. The modified degree is 75 % by 1H NMR analysis. GPC analysis indicated that after modification the hyperbranched polyester has higher molecular weight and wider distribution than before.The UV curing of VHBP is also investigated in this paper. It was found that conversion rate of vinylic double bond was nearly 100 % after curing 40 s by using photoinitiators in dosages of 5 % Irgacure 2959. The obtained coating represented superior properties. The curvature radius of the coating is 0.5±0.1 mm, the adhesion is 1 grade, it also has better handness,acid resistance, alkali resistance and water resistance.