Study On Microstructure And Properties Of Curved Round Bamboo For Furniture

Phyllostachys iridescins,as a representative small bamboo,has a great development prospect in the field of home furnishment.The rational exploitation and utilization of red bamboo resources is helpful to promote the sustainable development of Chinese bamboo industry.The differences of microstructure,chemical composition and physical and mechanical properties of different parts of round bamboo after bending were studied,and the macroscopic phenomena such as dimensional stability and non-deformation of round bamboo components after bending were understood from the microscopic and macroscopic perspectives.The study on the characteristics of bamboo in stable state after bending has important guiding significance for the forming processing of bamboo and the construction of bending parts,and provides theoretical basis for the industrial utilization of round bamboo bending.Therefore,this paper takes Phyllostachys iridescins as the main research object.Electron microscope(SEM),X-ray diffractometer(XRD),Fourier infrared(FTIR),optical microscope,Laser confocal microscope(CLSM),water contact Angle tester,universal mechanical testing machine and DMTA analysis tester were used to analyze the Phyllostachys iridescens)microstructure,chemical composition and structure,physical and mechanical properties were measured and analyzed.The main research results are as follows:(1)The degree of deformation of the convex side of curved round bamboo cells is greater than that of the concave side.From the cross section,the degree of deformation of bamboo tissue cells was as follows: parenchyma cells were the most serious,duct and sieve tubes followed,and fiber cells were almost unchanged.According to the diameter section,the concave side cells of the curved round bamboo were severely deformed,while the convex side cells were slightly deformed.Viewed from the chord section,the curved round bamboo parenchyma cells are long and narrow,the cell wall is torn and the surface is broken.From the view of the wall structure,the wall structure of the curved round bamboo thin-walled cell extends and distorts towards the cell cavity,and the surface is damaged,but the overall structure remains unchanged.The fiber cells had multilayer structure,and the wall structure did not break.The radial width and chord width of curved round bamboo vascular bundle increase,and the ratio of diameter to chord decreases.The roundness of the curved round bamboo conduit decreased,the roundness of the convex side was less than that of the concave side,the length-diameter ratio increased,and the length-diameter ratio of the convex side was greater than that of the concave side.The roundness of the parenchyma cells decreased,the roundness of the convex side was lower than that of the concave side,and the ratio of length to length of the convex side was higher than that of the concave side.From bamboo green to bamboo yellow,the roundness and length-diameter ratio of fiber cells changed little.(2)After bending round bamboo,the chemical environment of lignin,cellulose and hemicellulose changes,and some characteristic functional groups shift.The chemical properties of the bending bamboo are more stable,and it is easy to maintain the stability of its bending state.After bending round bamboo,the number of hydroxyl groups decreases,the hygroscopicity decreases,and the dimensional stability is good.According to semi-quantitative analysis of infrared spectrum,the chemical content difference between convex side and concave side is less than 1%.The quality of curved round bamboo was decreased,and the convex side was lower than the concave side.The secondary wall of fiber cells showed an alternating thick-thin structure,and the lignin concentration of thick layer was different from thin layer.The spontaneous fluorescence intensity of lignin in vascular bundle,parenchyma cell and fibrous sheath decreased after the bending of round bamboo,and the fluorescence intensity changed: convex side < concave side < pair.The self-fluorescence intensity of vascular bundle decreased gradually from inside to outside,which showed that the fluorescence intensity of lignin near the duct and sieve tube was high,but gradually decreased when it was transferred to parenchyma cells.(3)The cellulose structure of curved round bamboo was changed.The crystallinity of the curved round bamboo decreased and the crystallinity of the convex side was higher than that of the concave side,Convex side decreased by 15% and concave side decreased by 42%.The crystallinity of the opposite,convex and concave sides is 37.94%,32.94% and 26.65% respectively.The characteristic peak intensity of(101)crystal plane became weaker.The average opposite microfibril Angle was9.50°,the convex microfibril Angle was 9.15°,and the concave microfibril Angle was 12.70°.Convex side decreased by 4%,concave side increased by 25%.The changes of microfibril Angle of bamboo in different stress positions were as follows: convex < opposite < concave.The radial variation trend of microfibril Angle of red bamboo increased first and then decreased from bamboo green to bamboo yellow,and the radial variation of microfibril Angle of red bamboo was little.(4)The physical and mechanical properties of the convex side of curved round bamboo are better than those of the concave side.The surface roughness of bamboo yellow is slightly higher than that of bamboo green.The water contact Angle in radial direction and chord direction increases after the bending of the round bamboo,and the chord contact Angle of the convex side is higher than that of the concave side.The bending strength and elastic modulus of bamboo in different parts are as follows: concave side < opposite side < convex side.The energy storage modulus of bamboo decreased with increasing temperature.In the parts of bamboo green and bamboo flesh,the variation trend of energy storage modulus was as follows: concave side < opposite side < convex side.The variation trend of energy storage modulus of red bamboo in different radial parts: bamboo yellow < bamboo meat < bamboo green.The loss modulus of bamboo first increased and then decreased with the increase of temperature.The loss modulus of red bamboo in different radial parts is bamboo yellow < bamboo meat < bamboo green.In the parts of bamboo green and bamboo flesh,the change of loss modulus of different parts is: concave side < opposite side < convex side.The loss Angle tangent value of curved round bamboo increases,and the convex side is less than the concave side.