| Motivated by people’s growing environmental awareness,epoxy coatings are witnessing a rise of high solid coating,solvent-free coating,and waterborne coating,which gradually take the place of traditional solventborne coating.Meanwhile,the preparation of commonly used chemical products,such as epoxy resin,from biofeedstock has become the hot topic of both academia and industry.In this thesis,different types of biobased hyperbranched epoxy resins were prepared using monomers derived from bioresources.And those hyperbranched epoxy resins were used to improve the anticorrosion performance and mechanical properties of epoxy resin coating materials.Taking advantage of the low viscosity characteristic of hyperbranched molecules,the solvent content of the coating system could also be further reduced by the addition of hyperbranched epoxy resins.The curing schedules of the environmentaly friendly coating systems were optimized for achieving better anticorrosion performance.Besides,the effects of the molecular structure and addition content of hyperbranched epoxy resins as well as solid content on the solvent effect of hyperbranched epoxy resin/DGEBA mixtures were investigated.Finally,several biobased phenolic aldehyde amine curing agents were prepared,and it’s structure-property relationships were studied.The main contents of the thesis are as follows:1.Biobased hyperbranched epoxy resins with rigid branching structure and flexible spacer segments were prepared by the polymerization between rigid biofeedstock resveratrol（A3 monomer）and different flexible difunctional epoxy resins（B2 monomer）.It is found that the viscosities of the hyperbranched epoxy resins are largely dependent on the flexibility of the B2 monomers.Moreover,the anticorrosion performances of the high solid content epoxy coating and solvent-free epoxy coating were significantly improved by the addition of those hyperbranched epoxy resins,and the best performance is achieved at7wt% addition content.The obtained high solid content coating layer could remain intact in10wt% H2SO4 for more than 50 d,whereas the unmodified one failed after 28 d.2.Hyperbranched epoxy resins were prepared based on A2 monomer with two hydroxyl groups and Bn monomer（n=3 or 4）with epoxide groups.The curing schedules were optimized based on the characteristic curing temperature corresponding to 0°C.min-1 heating rate,which were obtained via applying T-β extrapolation methods to the DSC data.The coating layer cured at 120 o C for 120 min shows superior anticorrosion performance than that cured at ambient temperature for more 6 h.The anticorrosion performance of the high solid content epoxy coating,solvent-free epoxy coating and waterborne epoxy coating were further improved by the addition of hyperbranched epoxy resins.And it is surprisingly found that the viscosity of hyperbranched epoxy resins derived from 2-hydroxybenzyl alcohol is even lower than that of liner epoxy resin E51,so this kind of hyperbranched epoxy resin not only can improve the chemical resistance of coating layer,but also can effectively reduce the solvent amount.3.Hyperbranched epoxy resins with unsaturated side chains were successfully obtained via polymerization of monomers which contain unsaturated side chain structure,i.e.magnolol,honokiol,and cardanol.The hyperbranched epoxy resins derived from magnolol and honokiol stop growing with increasing reaction time when it’s molecular weights increase to some constant values,that is beneficial for batch stability.The bulk viscosity and solution viscosity of biobased hyperbranched epoxy resin with unsaturated side chains and it’s mixture with common E51 epoxy resin were also investigated.Those hyperbranched epoxy resins also could effectively improve the corrosion resistance of high solid epoxy coating and solvent-free epoxy coating.Among them,both high solid epoxy coatings with 7wt% magnolol-based hyperbranched epoxy resin and 7wt% honokiol-based hyperbranched epoxy resin show excellent corrosion resistance properties,which could remain intact in 10wt% H2SO4 for 38 d and 35 d,respectively.In addition,those biobased hyperbranched epoxy resin with unsaturated side chains could be cured employing dual cure approach,in which the reaction between epoxide group and curing agent is induced by thermal heat,and the polymerization of double bond is induced by light.4.A series of biobased phenolic aldehyde amine curing agents with twin side chains were prepared using magnolol,honokiol,polyformaldehyde and polyamine.And they were used to cure flexible aliphatic epoxy resins.After UV/heat dual cure,a cured product with a Tg of ca.80 °C and storage modulus of 3 GPa were obtained. |
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