| Imitated precious wood is a novel macromolecular material that can be widely applied to handicraft and furniture making.This novel material overcomes several difficulties in handicraft manufacturing,such as single color,poor durability,and high cost.In addition,it is significant for China lacking precious wood while abounding in fast-growing wood.However,there is one problem to be tackled,i.e.,how to achieve an effective combination of softwood compaction and waxing for improving the soft base material(imitated precious wood)with poor surface properties,especially lacking luster,thus utilizing low-end wood in a low-cost,efficient,and high-value-added way.Therefore,we examined the impacts of hot pressing and the superheated steam treatment under high temperature and pressure on the mechanical properties,microstructure,hydrophobicity,permanent deformation and chemical properties of a fast-growing poplar wood,Populus ussuriensis Kom.We also optimized these two processes for synchronous,permanent deformation of heartwood and sapwood.Additionally,we developed an optimized material ratio for beeswax modification,studied the wood processing by modified beeswax,and discussed the design and market value with respect to handicrafts made of imitated precious wood.Our findings provide an important guide for manufacturing of handicrafts based on the imitated precious wood transferred from low-quality wood.Main components and results of this article are as follows:1)First of all,the background of wooden craft industry was summarized to elicit the research and application of imitated precious wood preparation technology in the domain of wood science.We made a systematic review and predicted the value of this paper,with emphases on permanent deformation of heartwood and sapwood by the superheated steam treatment under high temperature and pressure,and application of modified beeswax to the surface of imitated precious wood.2)We used a fast-growing poplar wood,Populus ussuriensis Kom,as test material,and studied two processes that can achieve permanent deformation of the wood,i.e.,hot pressing and superheated steam treatment under high temperature and pressure.The mechanical properties,microstructure,hydrophobicity and chemical properties of heartwood and sapwood before and after various processes were tested and analyzed,so as to determine optimal parameters of the two processes for synchronous permanent deformation of heartwood and sapwood.The optimized process parameters are as follows:hot pressing at 160 ? for 15 min,with the compression pressure of 5 MPa;subjected to superheated steam treatment under high temperature and pressure for 1 h,leading to a 60%compression ratio(with 0%recovery within 7 d).The experiment under optimized conditions conformed to the original expectation of compressing heartwood and sapwood permanently and synchronously.Comparative experiment shows that for treated heartwood and sapwood,cells deformed largely and cell cavities shrank markedly,but cell walls remained intact.In comparison to crude material,the carbon element in treated heartwood increased while the oxygen element decreased,showing the same tendency as in treated sapwood.Celluloses,hemicelluloses and lignins in treated heartwood and sapwood softened and degraded,with less free hydroxyl groups and weak hygroscopicity;meanwhile,dimensional stability,density and hardness were all increased.Dynamic thermomechanical analysis on the treated heartwood and sapwood demonstrates that as the experimental temperature rose,storage modulus fell rapidly while loss tangent increased sharply.The treated wood cannot be used at an temperature over 90?.3)The parameters for surface treatment of imitated precious wood were optimized as follows:rough grinding with 240-grit abrasive paper at the speed of 1 min/cm2,combined with wet grinding with 400-grit abrasive paper at the speed of 2 min/cm2.The parameters for modified-beeswax treatment on imitated precious wood were also optimized:beeswax dosage 15 g/cm2,wax-stripping time 2 min/cm2,baking temperature 70?.4)The beeswax modified at varying ratios of Nano Ti02,chitosan,acid dye and neutral dye was applied onto the imitated precious wood prepared with a poplar wood,whose heartwood and sapwood had been synchronously deformed through optimized hot pressing and superheated steam treatment under high temperature and pressure.The specimens treated by varying modified beeswax were examined to compare their thermostability,permeability,colorimetric parameters,hydrophobicity,gloss and grain.On this basis,the composition of and treatment by modified beeswax were modified.In this section,the following findings were obtained.The N,S and Ti elements in modified beeswax permeated into the imitated precious wood,making the wood's surface color more variable.The optimal waxing effect was achieved at the ratio of 10 g beeswax plus 0.2%chitosan and 0.05%neutral red(mass ratio).when the surface of specimens was dyed evenly,with improved durability,gloss,contact angle and grain.Visual and tactile psychological magnitude regarding the imitated precious wood polished with the modified beeswax were scaled.In terms of visual feeling,the waxed specimens were warm,soft,elegant,and natural,but less vibrant or luxurious.They also delivered warm,soft and delicate touch,and generated no uncomfortable feelings,such as viscous,chill,plastic-like,and rough.To some extent,it felt good to touch these waxed wood specimens,but their surfaces were not smooth enough.5)The design and market value of handicrafts made of imitated precious wood were also studied.Frog,fish,tiger,dragon,taotie(a mysterious monster in ancient Chinese mythology),phenix,flower,plant and other traditional Chinese patterns were studied for pattern redesigning for those handicrafts made of imitated precious wood.On the premise of development and heritage,we designed a craft with the imitated precious wood as raw material,and studied how to achieve this design through sculpture. |
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