Effects of thermal modification on the physical, chemical and micromechanical properties of Masson pine wood (Pinus massoniana Lamb.)

Holzforschung ◽  
2018 ◽  
Vol 72 (12) ◽  
pp. 1063-1070 ◽  
Author(s):  
Xinzhou Wang ◽  
Xuanzong Chen ◽  
Xuqin Xie ◽  
Yan Wu ◽  
Linguo Zhao ◽  
...  
Keyword(s):  
Cell Walls ◽  
Lignin Content ◽  
Chemical Properties ◽  
Pinus Massoniana ◽  
X Ray Diffraction ◽  
Masson Pine ◽  
X Ray ◽  
Pinus Massoniana Lamb ◽  
Wet Chemical ◽  
Thermally Modified Wood

AbstractIn an attempt to evaluate the effects of thermal treatment on wood cell walls (CWs), Masson pine (Pinus massonianaLamb.) wood was thermally modified (TM) at 150, 170 and 190°C for 2, 4 and 6 h, respectively. The chemical properties, cellulose crystallinity (CrI) and micromechanics of the control and thermally modified wood (TMW) were analyzed by wet chemical analysis, X-ray diffraction and nanoindentation. The relative lignin content andCrI increased after the TM partly degraded the amorphous wood polymers. The relative lignin content was higher in TMW and the equilibrium moisture content decreased. Moreover, the elastic modulus (Er) and hardness (H) of TMW were lowered along with the creep ratio decrement (CIT) of CWs. However, a severe treatment (e.g. 190°C/6 h) may negatively affect the mechanical properties of CWs caused by the partial degradation of hemicelluloses and also cellulose.

The effects of thermal treatment on the nanomechanical behavior of bamboo (Phyllostachys pubescens Mazel ex H. de Lehaie) cell walls observed by nanoindentation, XRD, and wet chemistry

Holzforschung ◽  
2017 ◽  
Vol 71 (2) ◽  
pp. 129-135 ◽  
Author(s):  
Yanjun Li ◽  
Chengjian Huang ◽  
Li Wang ◽  
Siqun Wang ◽  
Xinzhou Wang
Keyword(s):  
Cell Wall ◽  
Thermal Treatment ◽  
Cell Walls ◽  
Treatment Time ◽  
Lignin Content ◽  
Phyllostachys Pubescens ◽  
X Ray Diffraction ◽  
Wet Chemistry ◽  
X Ray ◽  
Wet Chemical

Abstract The effects of thermal treatment of bamboo at 130, 150, 170, and 190°C for 2, 4, and 6 h were investigated in terms of changes in chemical composition, cellulose crystallinity, and mechanical behavior of the cell-wall level by means of wet chemical analysis, X-ray diffraction (XRD), and nanoindentation (NI). Particularly, the reduced elastic modulus (Er), hardness (H), and creep behavior were in focus. Both the temperature and treatment time showed significant effects. Expectedly, the hemicelluloses were degraded and the relative lignin content was elevated, while the crystallinity of the cellulose moiety was increased upon thermal treatment. The Er and H data of the cell wall were increased after 6 h treatment at 190°C, from 18.4 to 22.0 GPa and from 0.45 to 0.65 GPa, respectively. The thermal treatment led to a decrease of the creep ratio (CIT) under the same conditions by ca. 28%. The indentation strain state (εi) also decreased significantly after thermal treatment during the load-holding stage.

scholarly journals Multi-Scale Evaluation of the Effect of Phenol Formaldehyde Resin Impregnation on the Dimensional Stability and Mechanical Properties of Pinus Massoniana Lamb.

Forests ◽  
2019 ◽  
Vol 10 (8) ◽  
pp. 646 ◽  
Author(s):  
Wang ◽  
Chen ◽  
Xie ◽  
Cai ◽  
Yuan ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Cell Wall ◽  
Dimensional Stability ◽  
Cell Walls ◽  
Phenol Formaldehyde ◽  
Pinus Massoniana ◽  
Swelling Properties ◽  
Masson Pine ◽  
Pine Wood ◽  
Pinus Massoniana Lamb

The local chemistry and mechanics of the control and phenol formaldehyde (PF) resin modified wood cell walls were analyzed to illustrate the modification mechanism of wood. Masson pine (Pinus massoniana Lamb.) is most widely distributed in the subtropical regions of China. However, the dimensional instability and low strength of the wood limits its use. Thus, the wood was modified by PF resin at concentrations of 15%, 20%, 25%, and 30%, respectively. The density, surface morphology, chemical structure, cell wall mechanics, shrinking and swelling properties, and macro-mechanical properties of Masson pine wood were analyzed to evaluate the modification effectiveness. The morphology and Raman spectra changes indicated that PF resin not only filled in the cell lumens, but also penetrated into cell walls and interacted with cell wall polymers. The filling and diffusing of resin in wood resulted in improved dimensional stability, such as lower swelling and shrinking coefficients, an increase in the elastic modulus (Er) and hardness (H) of wood cell walls, the hardness of the transverse section and compressive strength of the wood. Both the dimensional stability and mechanical properties improved as the PF concentration increased to 20%; that is, a PF concentration of 20% may be preferred to modify Masson pine wood.

The combined effects of initial microfibrillar angle and moisture contents on the tensile mechanical properties and angle alteration of wood foils during tension

Holzforschung ◽  
2017 ◽  
Vol 71 (6) ◽  
pp. 491-497 ◽  
Author(s):  
Hankun Wang ◽  
Zixuan Yu ◽  
Xuexia Zhang ◽  
Dan Ren ◽  
Yan Yu
Keyword(s):  
Tensile Properties ◽  
Microfibril Angle ◽  
Tensile Modulus ◽  
Pinus Massoniana ◽  
Combined Effects ◽  
X Ray Diffraction ◽  
Masson Pine ◽  
X Ray ◽  
Microfibrillar Angle

Abstract The combined effects of initial microfibril angle (MFA) and moisture content (MC) on the longitudinal tensile properties of Masson pine (Pinus massoniana Lamb.) wood foils has been investigated. Synchrotron X-ray diffraction (XRDsyn) combined with a custom-built microtensile device was applied for in situ monitoring of the MFA alterations in the foils under different initial MFAs and MCs conditions. The results demonstrate that the tensile properties are highly negatively correlated to both MFA and MC. Furthermore, the tensile modulus is more sensitive to MC change than tensile strength. At a higher MFA, the sensitivity of the two mechanical indicators to MC alteration is enhanced.

Variation of surface and bonding properties among four wood species induced by a high voltage electrostatic field (HVEF)

Holzforschung ◽  
2019 ◽  
Vol 73 (10) ◽  
pp. 957-965 ◽  
Author(s):  
Qian He ◽  
Tianyi Zhan ◽  
Haiyang Zhang ◽  
Zehui Ju ◽  
Lu Hong ◽  
...  
Keyword(s):  
High Voltage ◽  
Electrostatic Field ◽  
Wood Species ◽  
Phenol Formaldehyde ◽  
Lignin Content ◽  
Chemical Properties ◽  
Pinus Massoniana ◽  
Populus Tomentosa ◽  
Chinese Fir ◽  
Masson Pine

Abstract A high voltage electrostatic field (HVEF) was applied to enhance the bonding performance of wood composites prepared with phenol-formaldehyde (PF) adhesive and different wood species and radial cut combinations. Four wood species including Masson pine (Pinus massoniana), Chinese fir (Cunninghamia lanceolata), poplar (Populus tomentosa) and ayous (Triplochiton scleroxylon) were studied. The results of HVEF-treatment turn out to be species-dependent, and are related to the anatomical and chemical properties of wood. It was demonstrated by a statistical approach that the lignin content is the most significant parameter with a good correlation coefficient (R2 > 0.8). High lignin content leads to high free radical concentration at the wood surface and the HVEF enhanced the adhesive penetration depth, the maximal density and the bonding strength (Bst) at the interphase. On the contrary, high extract contents and large lumina diameters negatively impacted the surface modification by HVEF. The magnitude of the effects was in the following order: ayous < poplar < Masson pine < Chinese fir.

scholarly journals Determination of the Effects of Superheated Steam on Microstructure and Micromechanical Properties of Bamboo Cell Walls Using Quasi-Static Nanoindentation

Forests ◽  
2021 ◽  
Vol 12 (12) ◽  
pp. 1742
Author(s):  
Tiancheng Yuan ◽  
Xiaorong Liu ◽  
Youming Dong ◽  
Xinzhou Wang ◽  
Yanjun Li
Keyword(s):  
Elastic Modulus ◽  
Cell Walls ◽  
Superheated Steam ◽  
Lignin Content ◽  
Crystallinity Index ◽  
X Ray Diffraction ◽  
Untreated Sample ◽  
X Ray ◽  
Micromechanical Properties

In this paper, quasi-static nanoindentation was applied for investigating the influence of superheated steam on microstructure and micromechanical properties of Moso bamboo cell walls. The changes of mico-morphology, chemical composition, cellulose crystallinity index, micro-mechanical properties of bamboo were analyzed via scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier transform infrared (FTIR), and nanoindentation. As expected, the content of hemicellulose and cellulose showed a downward trend, whereas the relative lignin content increased. Elastic modulus and hardness of the cell wall increased compared with that of the untreated sample. The elastic modulus and hardness of bamboo increased from 11.5 GPa to 19.5 GPa and from 0.35 GPa to 0.59 GPa. Furthermore, results showed that the creep resistance positively correlated to treatment severity.

scholarly journals Born out of Fire and Ice: Polymorph Studies of the Antiviral Famciclovir

Crystals ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 129
Author(s):  
Liana Vella-Zarb ◽  
Ulrich Baisch
Keyword(s):  
Variable Temperature ◽  
Chemical Properties ◽  
Crystal Form ◽  
X Ray Diffraction ◽  
Crystal Forms ◽  
X Ray ◽  
Physical Chemical ◽  
Diffraction Patterns ◽  
Crystalline Forms

There is much interest and focus on solid forms of famciclovir. However, in spite of the abundance of reported differences in oral bioavailability, compressibility, and other physical–chemical properties of the various crystal forms of this drug, very little precise structural analysis is available in the literature to date. The form used in the commercial formulation is the anhydrous form I. Patents and patent applications report three different anhydrous crystalline forms on the basis of unindexed powder diffraction patterns. Single-crystal and variable-temperature X-ray diffraction experiments using the commercially available anhydrous form of famciclovir were carried out and led not only to the crystal structure determination of the anhydrous form I, but also to discovery of a new crystal form of anhydrous famciclovir from powder data.

Thinning effects on forest evolution in Masson pine (Pinus massoniana Lamb.) conversion from pure plantations into mixed forests

2020 ◽  
Vol 477 ◽  
pp. 118503
Author(s):  
Cheng Deng ◽  
Shougong Zhang ◽  
Yuanchang Lu ◽  
Robert E. Froese ◽  
Xiaojun Xu ◽  
...  
Keyword(s):  
Pinus Massoniana ◽  
Mixed Forests ◽  
Masson Pine ◽  
Pinus Massoniana Lamb
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