| Bamboo,as an important biomass resource in China,has many advantages such as strong reproducibility,rapid growth and excellent strength.However,the processing and utilization of bamboo are extremely difficult,because of the unique structural characteristics of bamboo.The comprehensive utilization rate of bamboo is low,which restricts the further development of the bamboo industry.Bamboo lignin,as the main residues,are mostly disposed of burning,which not only causes a great waste of resources but also has a very bad impact on the environment in the context of carbon neutrality.Therefore,the diversification and high-value utilization of bamboo lignin become very important.Aiming at the above problems,the bamboo lignin was transformed into bio-based epoxy resin with the goal of high-value utilization of bamboo lignin,and the structure and curing mechanism of bamboo lignin epoxy resin were systematically studied.To give full play to the characteristics of bamboo lignin,new bamboo lignin epoxy resin system with green,multi-structure and multi-function were prepared by using microwave method,nano precipitation method and in-situ self-assembly technology,and the structural properties of different bamboo lignin epoxy resin systems were characterized and tested.The main research results are as follows:（1）In this study,bamboo lignin was used as raw material,epoxidized bamboo lignin was synthesized directly by one-step method,and the curing reaction was carried out with common curing agents.The curing behavior and curing mechanism of bamboo lignin-based epoxy resin（epoxidized bamboo lignin）were explored.Bamboo lignin could be directly synthesized into the bio-based epoxy resin via one-step method,and the characteristic of epoxy groups of bio-based epoxy resin was proved by NMR and FTIR spectra.The epoxy equivalent of bamboo lignin-based epoxy resin was 350～400 g/mol,and the weight average molecular weight was 4835 g/mol.The curing kinetics of bamboo lignin-based epoxy resin with six curing agents showed that the curing reactions were all first-order reactions,and PEA-230 had the lowest activation energy of 46.2 k J/mol.（2）From the perspective of toughening and strengthening,nano-Ti O2/regenerated cellulose binary hybrid particles with strengthening and toughening effect were prepared by low-temperature dissolution technology and microwave-assisted in-situ growth self-assembly technology.Among them,regenerated cellulose has smaller size and better stability.Nano titanium dioxide can be stably deposited on the surface of regenerated cellulose by microwave-assisted method.The titanium dioxide particles deposited on the surface of cellulose were spherical anatase nano titanium dioxide with a diameter of less than 20 nm.In addition,nano-Ti O2/regenerated cellulose hybrid particles had better thermal stability,and the initial degradation temperature was increased by about 27%.Nano-Ti O2/regenerated cellulose binary hybrid particles showed good toughening and strengthening effect.Among them,the tensile strength and impact strength of bamboo lignin-based epoxy resin system modified by nano-Ti O2/regenerated cellulose binary hybrid particles were increased by 56%and 40%.Therefore,bamboo lignin-based epoxy resin system with high toughness and good strength was successfully prepared.（3）From the perspective of functionalization,bamboo lignin-based epoxy resin particles and nano titanium dioxide composite nanoparticles were prepared by nano precipitation method and liquid phase deposition self-assembly technology.Bamboo lignin-based epoxy resin composite system with UV protection and antibacterial was prepared by adding bamboo lignin-based epoxy resin particles and nano titanium dioxide composite nanoparticles.The composite nano materials had stable spherical topological surface shape,good dispersion,uniformity,UV resistance and antibacterial activity.Adding composite nano materials to bamboo lignin-based epoxy resin could prepare a functional bamboo lignin-based epoxy resin with good antibacterial activity and enhanced UV barrier performance.（4）A pure biological one component epoxy nanoparticle waterborne adhesive was designed.The structure,morphology,stability,formation mechanism,bonding ability and curing characteristics of the aqueous particle adhesive were studied.The results showed that the lignin-based aqueous nanoparticle adhesive was smooth and spherical,the particle size was about 90 nm,and had good dimensional stability.Bamboo lignin-based waterborne nanoparticle adhesive had good performance of bonding wood veneer,and the dry bonding strength could reach 4.8 MPa.In addition,bamboo lignin-based waterborne nanoparticle adhesive had good storage stability.Bamboo lignin-based waterborne nanoparticle adhesive was a one component adhesive,which can complete self-curing without adding curing agent.The activation energy Ea value of curing reaction of bamboo lignin-based waterborne nanoparticle adhesive was about 60 kJ/mol. |
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