Study On Aging Resistance Of Modified Polyethylene Waxed Wood

In view of the problems of high cost,low yield and poor surface properties and durability of the wax layer used in traditional waxing wood,which cannot meet the decoration quality of wood products and industrial requirements,researchers adopted industrial wax for wood surface waxing to reduce the cost.Polythene wax is a promising raw material for wood surface hot wax due to its wide source,low cost and non-toxicity.However,it is difficult to chemically combine with wood by using polyethylene wax directly,and its anti-aging ability is weak.Modification of polyethylene wax can effectively solve this problem.In this paper,maleic anhydride grafted polyethylene wax,doped with nano-sio₂ and nano-tio₂ to prepare functional nano-modified polyethylene wax with similar properties to natural wax,to replace natural wax,to achieve a better combination of wood and wax;Investigate the properties of hydrophobicity,glossiness,color difference,roughness and water resistance of wood surface modified by different amounts of nano-sio₂and nano-tio₂ modified polyethylene wax and wood surface after ultraviolet accelerated aging,and from the chemical composition of nano-modified polyethylene wax and wood and the interface bonding characteristics of wood surface and wax layer after waxing.The interfacial binding mechanism of wood with beeswax and nano-modified polyethylene wax was explored.And the aging resistance mechanism of polyethylene wax modified by adding nano-sio₂ and nano-tio₂,and determine the optimized method of modified polyethylene wax.The main conclusions of this paper were as follows:（1）The acid value of beeswax was 17.6（KOHmg/g）,the acid value of modified polyethylene wax was better than that of natural wax when MAH dosage was 1%,BPO dosage was 1.5%,reaction temperature was 150℃,reaction time was 2h,the effect of adding nanomaterials on the acid value was not significant,to achieve the simulation of the main chemical properties of beeswax;Thermograying analysis（TG）showed that the thermal stability of nano-modified polyethylene wax was significantly higher than that of beeswax.DSC analysis showed that the initial melting temperature of nano-modified polyethylene wax was significantly higher than that of beeswax,and both were greater than 100℃.The surface of nano-modified polyethylene wax was not easy to be destroyed in the process of daily use.FTIR analysis showed that the nano-modified polyethylene wax and beeswax had similar chemical structure,and maleic anhydride was successfully grafted onto the polyethylene wax,introducing polar groups such as cyclic anhydride,and chemical bonding between the nanomaterials and modified polyethylene wax made it easy to combine with wood surface.（2）The nano-modified polyethylene wax was embedded in the pores of the cell cavity and cell wall in the form of rivets,and reacts with the cellulose hydroxyl group in the cell wall of wood through the acid anhydride group,so that chemical bonding occurs between the wax layer and wood.The addition of nano-materials can enhance the chemical bonding between the wax layer and wood,and the beeswax and wood were mainly physical bonding at the interface.When the amount of nano-sio₂ was 1%,the water resistance of nano-sio₂modified polyethylene wax increased by 24.86%and 21.18%compared with beeswax and modified polyethylene wax,the surface roughness decreased by 83.22%and 44.04%,and the glossiness and hydrophobicity of nano-sio₂ modified polyethylene wax increased significantly compared with modified polyethylene wax.When the amount of nano-tio₂ was0.5%,the water resistance of nano-tio₂ modified polyethylene wax increased by 41.58%and38.72%compared with beeswax and modified polyethylene wax wood,the surface roughness decreased by 79.69%and 41.26%,and the glossiness and hydrophobicity of nano-tio₂ modified polyethylene wax increased significantly compared with modified polyethylene wax.Nano-modified polyethylene wax can replace natural wax for wood surface percolating.When the addition amount of nano-sio₂ and nano-tio₂ was 1%and 0.5%respectively,better surface properties of wood percolating can be obtained.（3）After 600h aging,the total discoloration rate of 1%nano-sio₂ modified polyethylene wax decreased by 30.14%and 17.99%compared with that of beeswax and modified polyethylene wax,and the surface roughness decreased by 36.79%and 16.72%.The glossiness and hydrophobicity were also significantly better than those of modified polyethylene wax.The total discoloration rate of 0.5%nano-tio₂ modified polyethylene wax increased by 41.1%and 18.08%than that of beeswax and modified polyethylene wax,and the surface roughness decreased by 66.1%and 41.77%.The glossiness and hydrophobicity were also obviously better than that of modified polyethylene wax.During the aging process of beeswax,the C-O-C chemical bond breaks to produce an unstable C=O bond,but the nano-modified polyethylene wax significantly slows down the fracture of C-O-C bond,and the addition of nanomaterials can significantly reduce the surface cracking of the wax layer after ultraviolet accelerated aging.The oxidation resistance of nano-modified polyethylene wax to wood was better than that of beeswax and modified polyethylene wax.In the actual use process,the color,gloss and smoothness of the surface of the nano modified polyethylene wax wax wood can be better maintained,prolong its use time,and had a good protective effect on the wood exposed to the sun for a long time.