Study On The Modification Of Phenolic Resin Using Eutectic Ionic Liquid Activated Lignin Catalysed Under Palladium Chloride

In the paper and pulp industries, kraft pulping is a main pulp. In the majority of cases, in order to reduce the economic cost, enterprises choosed few recycling, kraft pulping would be discharged into rivers or in situ burning. These practices not only wasted a lot of material resources, but also seriously polluted the environment. Therefore, a large number of research scholars researched how to modify the industrial alkali lignin, there were chemical, physical, biological and other methods. Although some progress had been made, taking into account the actual cost of the economy and the reality of the experiment itself and other factors, most of the modified methods were still stuck in the laboratory, it was difficult to form large-scale industrial utilization. The chemical structure of lignin molecular is similar to that of phenol, so we can make use of lignin which was replaced for phenol to product phenolic resin. However, due to the low chemical activity of lignin, its utilization has been greatly restricted. In order to improve the reaction activity of lignin, in this paper, the eutectic ionic liquid was synthesized by using choline chloride and urea as raw materials, by controlling the molar ratio of raw materials, temperature and time, to determine the optimal process conditions for the synthesis of the eutectic ionic liquid system. On this basis, the sddition of palladium chloride catalyst, to investigate the effect of different dosage on lignin structure. On this basis, the effect of joining the different dosage of palladium chloride catalytic on lignin chemical reactivity were studied. A combination of several techniques UV, FT-IR, 1HNMR were used in this work. Then the modified lignin replaced part of phenol to product phenolic resin adhesive, by testing the thermal and mechanical properties of lignin phenol glue to determine the amount of lignin. In order to reduce the cost and time of the experiment, so that the experiment will be popularized and applied. The recycling and utilization of the eutectic ionic liquid of palladium chloride, A combination of several techniques UV, XPS, XPS were used in this work. The main conclusions of the study are as follows:In the synthesis of the eutectic ionic liquid, the influence of molar ratio of raw materials on the yield was the most obvious, followed by reaction temperature, Finally, the reaction time. From orthogonal experiment analysis, the molar ratio of choline chloride and urea was 1:2, the reaction temperature was 80?, the reaction time is 0.5 hours, and the high yield can be obtained. In addition, the viscosity, conductivity and thermal stability were in the best condition.Under the optimal conditions, the chemical structure of lignin was modified by the addition of catalytic addition of palladium chloride in the synthesis of the eutectic ionic liquid. The main functional groups varied greatly, total phenolic hydroxyl content increased significantly. In several processing conditions, the ionic liquid and the lignin mass ratio is 10:1, the processing time of 2h, temperature of 90?. When adding palladium chloride catalyst for wood quality 10% the modification effect is the best. From the UV spectrophotometer data analysis showed that modified lignin total phenolic content increased by 152%, [OH?]increased 588%,and [OH?] more the reaction activity, In order to prove that the lignin reaction activity increased. From the analysis of the infrared spectra data show that Lignin degradation, chemical bonding parts of fracture, functional groups of high reactivity increased. From the 1HNMR spectral analysis data show that modified lignin methoxyl content and decreased by 48.57%, phenolic hydroxyl and alcoholic hydroxyl content increase, aromatic hydrogen increased. The reduce the condensation reaction of lignin molecular structure between the units, which proves that the lignin reaction activity increased.Before and after modification of the preparation of wood lignin phenolic resin with lignin increased in replace part of phenol system, the adhesive curing speed quickly, but the bonding strength of plywood decreased continuously, at the same time, the content of free formaldehyde increased with increasing amount of substitution. Comprehensive performance and cost reduction requirements, When the modified lignin phenol substitution amount was 40%, the bonding strength reached 1.29 Mpa, and the plywood pressed in line with the national I class plywood standard, realizing the improvement of the environment and conserve resources target.Through XPS photoelectric spectrometer, UV spectrophotometer, scanning electron microscope three kinds of different instruments for the characterization and analysis of lignin show that the eutectic ionic liquid on lignin modified with catalytic effect of palladium chloride. And to achieve 3 recycling, the effect of modified lignin and modified for the first time effect is basically the same. which can greatly reduce the cost of the experiment and the experimental time, In order to make the experiment can be popularized, and industrial production, achieve the purpose of turning waste into treasure.