Study Of Woodcut Heat Treatment Technology And Property

The demand for extension plates of woodcut is gradually increasing since China has paid a lot of attention on woodcut,one of the intangible cultural heritages.However,the traditional high-quality extension plates has been gradually reduced and normally the breadth is small.In this case,we introduced the high temperature thermal modification technology into the performance improvements of woodcut wood,two wood species,elm and basswood were employed.Several properties closely related to the performance of two woods were investigated,which included the physical and mechanical properties of untreated and thermal modified wood(density,flexural strength,flexural modulus,hardness,abrasion resistance,and surface wettability),the dimensional stability(radial swelling rate,chordwise swelling rate and hygroscopicity),the cutting performances(transverse cutting force and longitudinal cutting force),and the changes in chemical properties.In present study,the performance requirements of woodcut wood were preliminarily formulated,besides,the high temperature thermal modified wood were also been used as woodcut wood,and part of the plate wood achieve the requirements of high-quality extension plates or commonly used extension plates.Several conclusions are shown as follow:1.The basic physical and mechanical properties of high-quality extension plates;the basic density ranged from 0.469 g.cm-3 to 0,77 g.cm-3;the air dry density ranged from 0.569 g.cm 3 to 0.94 g.cm-3;the radial shrinkage rate from green wood to air-dry wood ranged from 0.9%to 3.2%;the chordwise shrinkage rate ranged from 1.3%to 5.3%;the surface hardness ranged from 4230 MPa to 8960 MPa,the lateral hardness ranged from 3300 MPa to 7410 MPa;the abrasion resistance was ?;the contact angle ranged from 35.53°to 76.20°.In addition,the basic physical and mechanical properties of commonly used extension plates:the basic density ranged from 0.36 g.cm-3 to 0.627 g.cm-3;the air-dry density ranged from 0.433 g.cm-3 to 0.62 g.cm-3;the radial shrinkage rate from green wood to air-drying wood ranged from 2.1%to 4.1%;the chordwise shrinkage rate ranged from 3.5%to 6.5%;the surface hardness ranged from 3481 MPa to 6400 MPa,the lateral hardness ranged from 2400 MPa to 5222 MPa;the abrasion resistance was?;the contact angle ranged from 30.05° to 76.50°.2.The oven-dry density,air-dry density,hardness,wear resistance and wettability of elm and basswood extension plates modified by high temperature reached the performance acquirements of high-quality extension plates or commonly used extension plates.3.The dimensional stability of elm and basswood extension plates was greatly improved after the modification by high temperature,and they reached the performance requirements of high-quality extension plates or commonly used extension plates.4.The organic solvent absorption of untreated and heat-modified extension plates:butanone>butyl acetate>ethanol>toluene.The effect of organic solvent on the dimension stability of the untreated and thermal-modified extension plates indicated that the radial swelling rate and chordwise swelling rate were decreased with the higher temperature and longer heat time.Moreover,the influence of four kinds of organic solvents on the swelling rate is quite different,it can be seen that the proportion change of organic solvent could reduce the influence on dimension stability of extension plates.5.The high temperature thermal modification effectively reduced the cutting force of elm and basswood extension plate,and the crosswise cutting force was greater than the longitudinal cutting force,which reduced the engraving difficulty.It is helpful for beginners to cut the plate.6.Once elm and basswood extension plate modified by high temperature,the cellulose content was less decreased,the hemicellulose was decreased significantly,and the proportion of lignin content was increased.The lignin had the strongest thermal stability among the three components,and relative content was not reduced but increased significantly after modified by high temperature.