Study On Modification Technology Of Fast Growing Wood Combination Impregnation Based On Phenolic Resin

Wood is produced in the late stage of plant differentiation or growth.It is the result of the plant cell wall becoming hard and firm due to the deposition of lignin produced in the cell,which plays a great supporting role in human life.Wood is divided into natural wood and fast-growing wood.Natural wood itself has good quality,long growth cycles,scarce resources,and high prices;fast-growing wood itself has poor quality,decay,discoloration,moth-eaten,short growth cycles,rich resources,and low prices.Therefore,the improvement of fast-growing wood is urgent.Synthetic resin is a kind of artificially synthesized high molecular weight polymer.According to their behavior classification,they are divided into thermoplastic resins and thermosetting resins.Among them,thermosetting resin refers to a resin that undergoes chemical changes after heating,gradually hardens and forms,and does not soften or dissolve when heated.It is characterized by heat resistance.High,difficult to deform under pressure,non-flammable,good dimensional stability,can be used to modify fast-growing wood.This thesis first studies the synthesis of phenolic resin,then selects the appropriate synthesis scheme and curing scheme,and uses phenolic resin to enhance the modification of fast-growing wood.By impregnation,we can briefly understand the impregnation modification of wood.Through the discussion of impregnation rate,we can It was found that the impregnation of the wood was not complete,and there were still many voids in the wood.Therefore,combined impregnation of wood can be considered,because the combined impregnation is still in the exploration stage.In the combined impregnation experiment,we choose unsaturated resin and shellac resin combined with phenolic resin combined impregnation,and then consider the viscosity of the resin,the type of curing agent,etc.Etc.,explore the combined impregnation from various aspects.I hope I can do my best.The experimental results show that the viscosity of the phenolic resin is 85 m Pa·s,which is defined as a high viscosity phenolic resin;the viscosity of the prepared phenolic resin is 15 m Pa·s,which is defined as a low viscosity phenolic resin.Using ammonium chloride curing agent,the curing degree is 93%.Three types of fast-growing wood are impregnated.The density of the poplar system is 0.74 g/cm~3,and the compressive strength can reach 112.61 MPa.The density of the Chinese fir system is 0.62 g/cm~3,and the compressive strength can reach 78.31 MPa.The density of the scotch pine system is 0.56g/cm~3,and the compressive strength can be Reached72.9 MPa.This shows that the properties of the wood after impregnation have been improved.The unsaturated resin has a viscosity of 55 m Pa·s,a solids content of 55%,and a degree of cure of 95%.The shellac resin has a viscosity of 65 m Pa·s and a solid content of 40%.The degree of curing is 85%.According to these three resins,the combination impregnation system can be divided into three types,a phenol-phenol resin system,a phenol-unsaturated resin system,and a shellac-phenol resin system.In the phenolic-phenolic resin system,the density of the poplar system combination is0.70 g/cm~3,and the compressive strength can reach 63.13 MPa;the density of the Chinese fir system combination is 0.58g/cm~3,and the compressive strength can reach51.04 MPa;The density after combined dipping is 0.54 g/cm~3,and the compressive strength can reach 65.30 MPa.In the phenol-unsaturated resin system,the density of the poplar system combination is 0.61 g/cm~3after immersion,and the compressive strength can reach 56.10 MPa;the density of the Chinese fir system combination is0.44 g/cm~3,and the compressive strength can reach 48.50 MPa;The combined density of the system after immersion is 0.57 g/cm~3,and the compressive strength can reach61.10 MPa.In the phenol-shellac resin system,the density of the poplar system combination is 0.70 g/cm~3after immersion,and the compressive strength can reach76.35 MPa;the density of the Chinese fir system combination is 0.57 g/cm~3,and the compressive strength can reach 38.00 MPa;The combined density of the system after immersion is 0.56 g/cm~3,and the compressive strength can reach 43.37 MPa.This shows that the properties of the wood after combination impregnation have been improved,compared with the impregnation system.In this paper,the impregnation rate,weight gain rate,water absorption rate,and cross-sectional density are also measured.FT-IR analysis of the impregnation solution,ATR analysis of the product before and after impregnation,and SEM and XPS analysis of the phenol-phenolic resin system are used to confirm the impregnation.The liquid is filled in the voids of the wood through vacuum curing,and then the wood is reinforced and modified to improve the various properties of the wood.