Preparation Of Hyperbranched Polymer And Its Application For Polyurethane Joint Sealant

The quality of cement concrete pavement joints is directly related to the lifetime ofcement concrete pavement. The research of high performance cement joints is very hard in theworld.The polymer of polyurethane modified with polysiloxane is the best cement concretepavement joints in our country,but its crossing-linking group is isocyanate.The carbon dioxidewill be appeared by the reaction of isocyanate and water, and the quality of cement concretepavement joints will be affected by the air bubbles. As a result, the construction ofpolyurethane joints is out of commission under the rain and snow.In order to make up for thisproblem,the polyurethane joints modified with hydroxyethyl acrylate and hyperbranchedpolyaminoester were prepared.The modified polyurethane joints cross-linked by redoxinitiation system（cyclohexanone peroxide/cobalt naphthenate） at room temperature was to betested.The research includes the following aspects:（1）The synthesis and characterization of the hyperbranched polyaminoesterThe different generations of hyperbranched polyaminoester were produced bytrimethylolpropane and AB₂-type monomer. IR, TGA and viscosity were tested for thehyperbranched polyaminoester. The results showed that the hyperbranched polyaminoesterhas a mass of hydroxyl group, low viscosity and good thermal stability.（2）The modification of hyperbranched polyaminoesterThe hyperbranched polyaminoester was modified by acrylic acid. IR was tested for thehyperbranched polyaminoester.The results show that the modified hyperbranchedpolyaminoester has a mass of C=C bonds and a few hydroxyl groups.（3）The preparation of the polyurethane joints modified with hydroxyethyl acrylate andhyperbranched polyaminoesterThe polyurethane joints modified with hydroxyethyl acrylate was prepared by thechemical reaction of hydroxyethyl acrylate and the prepolymer of polyurethane modifiedwith polysiloxane. The polyurethane joints modified with hyperbranched polyaminoester wasprepared by the chemical reaction of hyperbranched polyaminoester and the prepolymer ofpolyurethane modified with polysiloxane.The plasticizer and kinds of tower packings were mixed to make the other component.（4）The choice of initiatorThe modified polyurethane cross-linked by AIBN,BPO, and redox initiation system atroom temperature were to be tested.The result showed that,the modified polyurethane jointswith1.0¹.3%cyclohexanone peroxide as initator had the best tack-free time.（5）The test of the modified polyurethane joints performanceThe tack-free time,tensile strength test,bonding strength were tested for the modifiedpolyurethane joints.The result showed that, G2is the best one of the polyurethane modifiedjoints,the date of tensile strength test is2.98MPa,the date of percentage ofbreaking-elongation is699.30,the date of bonding strength is1.32MPa. The result alsoshowed that3050/2000is the best one of the polyurethane joints modified with hydroxyethylacrylate,the date of tensile strength test is2.75MPa,the date of percentage ofbreaking-elongation is610.23%,the date of bonding strength is1.08MPa.All of the colloidscross-linked by C=C bonds have the stable performance in water test.