| Two-component waterborne polyurethanes (2K-WPUs) which combine high performanceof two-component solvent based polyurethanes and environmental friendliness, safety ofwaterborne systems together, have been grown as hotspots of coating research in both domesticand overseas, and have been increasingly applied in surface finishing, protection and adhesionfor cars, wood, plastic, industrial maintenance, etc. China is the main turpentine producingcountry, and its turpentine annual output is80000-100000tons. Turpentine is widely used assolvent due to the low level of deep processing and utilization.Terpene-maleic ester type epoxy resin (TME) which is an alicyclic epoxy resin withendocyclic structure was synthesized from the raw material turpentine. In this paper,waterborne polyols were synthesized from TME by hydroxylation and hydrophilization. Thenthe TME-based polyols were crosslinked with polyisocyanate to prepare two-componentwaterborne epoxy resin/polyurethane composite systems. The main topics of this thesis are asfollows:(1)the synthesis and characterization of TME-based polyols, and the stability,rheological property and particle size distribution of the polyol dispersions;(2)the kinetics ofcrosslinking reaction between TME-based polyols and polyisocyanate, and the effects of polyolstructures on reaction mechanism;(3)the rheological property and film formation of thewaterborne composite systems, and the effects of polymer structures on properties of thecomposite products. The purpose of this study is to provide favorable theoretical basis forhigher value and more efficient application of the renewable terpene resource on preparationfor environment-friendly polymer materials.1. Nonionic TME-based polyol (NTP) dispersion was prepared by modifying TME withpolyethylene glycol. The best synthesis condition of polyols was confirmed by studying aboutreaction influence factors. When reacted at110-120℃for about1h,good quality product canbe obtained by using polyethylene glycol with molecular weight of6000as hydrophilic segment which desirably accounts for8%by weight based on the weight of TME, andsulphuric acid as catalyst which accounts for1.5%by weight based on the weight of TME.NTP is transparent yellow solid with hydroxyl value of100mg/g, hydroxyl group content of3.04%. NTP dispersion is milk-white liquid with solid content of40%, viscosity of150mPa·s,Z-average particle size of200nm. The apparent viscosity of NTP dispersion decreases with theincreasing of shear rate, which indicates NTP dispersion is Pseudoplastic fluid.2. Cationic TME-based polyol dispersions were prepared by modifying TME withdiethanolamine. Suitable synthesis condition of polyols was confirmed by studying on factorsof synthesis reaction. Good quality polyols can be obtained by TME reacting withdiethanolamine in the amount of12%of TME by weight and chain extenders whose molarratio to TME (the quantities after reacting with amido of diethanolamine) is1–1.2:1attemperature of100℃for about6–7h in the present of ZnCl2as catalyst with the amount about2%of TME by weight. Cationic TME-based polyols are transparent yellow solids withhydroxyl value of230-260mg/g, hydroxyl group content of6.97-7.88%. Cationic TME-basedpolyol dispersions are transparent yellow liquids with solid content of30%, viscosity of1700-3700mPa·s, Z-average particle size of20-40nm. The apparent viscosity of cationicpolyol dispersions remains constant with the increasing of shear rate, which indicates cationicpolyol dispersions are Newton fluid.3. Anionic TME-based polyol (T-PABA) dispersion was prepared by modifying TME withpara-aminobenzoic acid. And suitable synthesis condition of polyol was confirmed by studyingon factors of synthesis reaction. When reacted at80-90℃for about3h,good quality T-PABAcan be obtained by TME reacting with para-aminobenzoic acid whose molar ratio to TME is1.6–1.8∶1,and using butanone as reaction solvent which desirably accounts for150%byweight based on the weight of para-aminobenzoic acid. T-PABA is transparent yellow solidwith hydroxyl value of170mg/g, amine value of126mg/g, and active hydrogen content of0.525mol/100g. T-PABA dispersion is transparent yellow liquid with solid content of30%,viscosity of400mPa·s, Z-average particle size of30nm. The apparent viscosity of T-PABA dispersion remains constant with the increasing of shear rate, which indicates T-PABAdispersion is Newton fluid.4. A kinetics analysis method for the bulk crosslinking reaction of waterborne epoxyresin/polyurethane composite systems prepared with TME-based polyol dispersions andhydrophilically modified hexamethylene diisocyanate (HDI) tripolymer was investigated withfreeze-drying and differential scanning calorimetry (DSC). And the data fit was realized withthe nth order kinetics equation and Málek's mechanism function method, respectively. Theresults showed that the nth order kinetics equations from Kissinger and Crane Equations werenot able to well describe the nonisothermal reaction rates of the waterborne composite systems.While the simulated curves acquired from Málek's mechanism function method matched wellwith the experimental dots in the investigated heating rate range. These results reflected thatthe autocatalytic model from Málek's method could be used well for the investigatedcrosslinking systems. The kinetic equations acquired from this model can be used to direct thetechnological parameters optimization of the2K-WPUs crosslinking process.In order to validate whether the kinetics models acquired from Málek's method can directthe isothermal crosslinking process, conversion coefficient curves calculated from obtainedkinetics equations were compared with ion viscosity curves from dielectric analysis. It could beobserved that these two types of curves matched quite well with each other. This resultindicated that the kinetics models gained from the Málek's mechanism function method couldwell describe the actual crosslinking reaction processes of the studied crosslinking systems.5. The rheological properties of the waterborne epoxy resin/polyurethane compositesystems were in conformity with that of the used polyol dispersions. Polyol dispersions couldemulsify the HDI tripolymer and reform new particles when the two components were mixed.The film formation process of2K-WPUs is as the following:(1) solvent, water volatilizing,(2)polyol particles and HDI particles merging together,(3) polyisocyanate reacting with polyoland water. The particle trails on the surface of composite products indicated that there were particle trails in the body of the film. This result confirmed the particles piling film formationmechanism of the2K-WPUs.The properties of the composite products are closely related to the chemical structures ofthe TME-based polyols. There is only secondary hydroxyl group whose reactivity is low whenreacting with isocyanate group in NTP structure. Therefore, the drying time of the compositesystem from NTP is long. T-PABA contains secondary amine group having high reactivity withisocyanate group, so the drying time of the composite system from T-PABA is short. CationicTME-based polyols have tertiary amine in structure, which can catalyze the reaction ofhydroxyl group and isocyanate group. The drying time of their composite systems is short too.Due to the presence of endocyclic structure of terpene, the composite products of thecomposite systems have many eximious properties, such as high gloss, good impact strength,adhesion, flexibility, antifouling, heat resistance and blocking resistance. The compositeproduct of T-PABA with benzene ring structure has the highest gloss and pencil hardness. Thewater resistance of the composite products is slightly inferior as a result of the presence ofhydrophilic groups. The drying time, pencil hardness, water-resistant and thermal-resistantproperties of the composite products increase with the molar ratio of NCO group to OH group.
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