Preparaiton And Properities Of Tung Oil Modified Rosin Resin

Rosin, as a renewable natural resource, has been extensively used as a raw material for the preparation of polymer because of the high chemical reactivity of the carboxyl group and conjugated double bond in its structure. However, the application was limited due to the exhibited rigidity, poor flexibility and brittle of synthetic polymeric materials with the hydrophenanthrene structure.In this study, the modified rosin resin containing flexible structures was prepared via Diels-Alder addition reaction between different amount of tung oil and rosin, and then which was induced to the synthesis of polymeric materials. Therefore, a series of the polymeric material of modified rosin resins with flexible characteristics were prepared, and the conclusions are as follows:Glycerin ester of tung oil modified rosin (GTR) was prepared by esterification of the addition product between tung oil and rosin. The Diels-Alder addition reaction between rosin and tung oil was proved by FT-IR characterization, GPC analysis, bromine value measurement and density function theory method. The results showed that increasing the amount of tung oil resulted in a significant decrease in the softening point of GTR and viscosity of its linseed oil solution, but a slight increase in the solubility and thermal stability. Applied GTR from different amount of tung oil into polyurethane (PU) adhesive, increasing the amount of tung oil led to an increase firstly and then decrease in the miscibility of GTR with PU and the T-peel strength of adhesive. The elongation at break of film increased monotonously, but tensile strengths increased firstly and then decreased with the increase of the amount of tung oil. The GTR with desired properties was prepared when mass ratios of tung oil and rosin were in the range from10:100to40:100.The glycerin ester of maleic anhydride-tung oil-rosin (MR) was prepared by esterification of the Diels-Alder adduct from maleic anhydride, tung oil and rosin. The results showed that the Mw, molecular weight distribution, softening point of MR and the viscosity of MR-linseed oil solution increased, but the n-pentane tolerance of MR decreased with the increase in the content of maleic anhydride. In addition, the Mw and molecular weight distribution of MR increased, but the softening point and n-pentane tolerance of MR decreased, the viscosity of MR-linseed oil solution unchanged almost while the increase in the content of tung oil. The MR with excellent comprehensive properties was obtained when the mole ratio of maleic anhydride and rosin was2:10, the mass ratios of tung oil and rosin were in the range from1:10to2:10.Rosin modified tung oil/octylphenolic resin (RTOP) was prepared from octylphenol, formaldehyde, tung oil and rosin. The results showed that increaseing the amount of tung oil, the molecular weight of RTOP and the viscosity of its linseed oil solution increased, but their softening point and n-heptane tolerance slightly decreased. RTOP with desired properties can be prepared when the mole ratio of octylphenolic and formaldehyde was1:1.8, mole ratio of rosin and octylphenol was1:0.7and the mass ratios of tung oil and rosin were within15:100.