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.

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 effect of high voltage electrostatic field (HVEF) treatment on bonding interphase characteristics among different wood sections of Masson pine (Pinus massoniana Lamb.)

Holzforschung ◽  
2018 ◽  
Vol 72 (7) ◽  
pp. 557-565 ◽  
Author(s):  
Qian He ◽  
Tianyi Zhan ◽  
Haiyang Zhang ◽  
Zehui Ju ◽  
Chunping Dai ◽  
...  
Keyword(s):  
Pore Size ◽  
High Voltage ◽  
Electrostatic Field ◽  
Phenol Formaldehyde ◽  
Dynamic Contact Angle ◽  
Treated Wood ◽  
Polarization Degree ◽  
Tangential Section ◽  
Masson Pine ◽  
Wood Surfaces

AbstractHigh voltage electrostatic field (HVEF) treatment has been investigated as an optimization method for enhancing the bonding performance of wood via increasing its polarization degree and improvement of the penetration of phenol formaldehyde (PF) adhesive. As the wood surfaces from cross cut (C), radial cut (R) and tangential cut (T) behave differently, five cut combinations formed the samples to be tested, namely C-C, R-R, R-T, T-T (always parallel to grain) and T-T⊥, where the grains were perpendicular to each other. The gluing and HVEF treatments were performed simultaneously. The sample surfaces were characterized by electron spin resonance (ESR) spectroscopy, dynamic contact angle (CAdyn) measurements, X-ray densitometry, fluorescence microscopy, Fourier-transform infrared (FTIR) spectroscopy and measurements of compression shear bonding strength (CSBS). An increased surface energy led to decreased CAdynS in the following order: cross section<tangential section<radial section. Obviously, the triggered free electrons of the HVEF treatments changed the wood surfaces. The penetration depth of PF into wood cell decreased significantly and the maximal density increased after the HVEF treatment. The lower CAdyns also contributed to the better reaction of the wood surface with the PF resin. The CSBS of the five sample combinations was enhanced owing to a better performance of adhesive aggregation, which was increased by 18% (C-C), 24% (T-T), 26% (T-T⊥), 31% (R-T) and 42% (R-R), respectively. Pore size and pore size distribution contributed a lot to the bonding properties of HVEF-treated wood sections.

scholarly journals Comparison of Bonding Performance Between Plywood and Laminated Veneer Lumber Induced by High Voltage Electrostatic Field.

2019 ◽  
Vol 275 ◽  
pp. 01013
Author(s):  
Qian He ◽  
Tianyi Zhan ◽  
Haiyang Zhang ◽  
Zehui Ju ◽  
Lu Hong ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
High Voltage ◽  
Electrostatic Field ◽  
Wood Surface ◽  
Bonding Strength ◽  
Surface Characteristics ◽  
Wood Failure ◽  
Photoelectron Spectra ◽  
Masson Pine ◽  
Laminated Veneer Lumber

High voltage electrostatic field (HVEF) was applied in order to improve wood surface characteristics, bonding and mechanical properties of wood composites. Masson pine (Pinus massoniana Lamp.) plywood and laminated veneer lumber (LVL) were selected in this study. Surface characteristics were conducted by the electron spin resonance (ESR) and X-ray photoelectron spectra (XPS). Bonding interphase and mechanical properties were investigated by fluorescence microscopy and vertical density profile (VDP), bonding strength, wood failure ratio, MOE and MOR. The results indicated that more increments were obtained in free radicals, O/C ratios and C2-C4 components. This is because electrons broke more wood chemical groups and new ions occurred among wood surface under HVEF. Significantly decreased PF adhesive penetration depth (PD) and increased density at bonding interphase was achieved in HVEF treated composites. More decrease of PD and increment of density were observed in plywood than that of LVL. This was attributed to cross linked wood fibers among bonding interphase in plywood. Mechanical properties of bonding strength, wood failure ratio, MOE and MOR were significantly increased under HVEF treatment both for two composites. Higher bonding strength, MOE and MOR were obtained in plywood and their increments were as 98.53%, 33.33%, 18.55% and 12.72%.

scholarly journals Influence of juvenile and mature wood on anatomical and chemical properties of early and late wood from Chinese fir plantation

2021 ◽  
Vol 67 (1) ◽  
Author(s):  
Changqing Lu ◽  
Jun Wu ◽  
Qianqian Jiang ◽  
Yamei Liu ◽  
Liang Zhou ◽  
...  
Keyword(s):  
Juvenile Wood ◽  
Lignin Content ◽  
Microfibril Angle ◽  
Chemical Properties ◽  
Decisive Role ◽  
Chinese Fir ◽  
Mature Wood ◽  
Chemical Components ◽  
Late Wood ◽  
Significant Difference

AbstractThe proportion of juvenile wood affects the utilization of wood seriously, and the transition year of juvenile wood (JW) and mature wood (MW) plays a decisive role in the rotation and the modification of wood. To find out the demarcation of JW and MW, the tracheid length (TL) and microfibril angle (MFA) of early wood (EW) and late wood (LW) from four Chinese fir clones were measured by optical microscopy and X-ray diffraction. Then the data were analyzed by the k-means clustering method. The correlation and the differences among wood properties between JW and MW were compared. Results indicated that the LW showed better properties than that of EW, but the anatomical differences between EW and LW did not influence the demarcation of JW and MW. The cluster analysis of TL and MFA showed that the transition year was in the 16th year and the transition zone of EW and LW was different among clones. The MW has longer and wider tracheid, thicker cell walls, and smaller MFA. In terms of chemistry, MW had a higher content of holocellulose, α-cellulose, less content of extract, but no significant difference in lignin content compared with JW. The stabilization of chemical components was earlier than that of the anatomic properties. Correlation analysis showed that there were strong correlations between the chemical composition and anatomical characteristics in JW and MW. In general, compared with chemical components, anatomical indicators were more suitable for JW and MW demarcation. The differences and correlations between JW and MW properties provide a theoretical basis for wood rotation and planting.

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.

Evaluation of soil and water conservation capacities for plantations on the Simian Mountains of China

2013 ◽  
Vol 89 (02) ◽  
pp. 178-183
Author(s):  
Jing Li ◽  
Dandong Chang ◽  
Jinhua Cheng ◽  
Hongjiang Zhang ◽  
Haofeng Huang
Keyword(s):  
Water Conservation ◽  
Ideal Point ◽  
Pinus Massoniana ◽  
Chinese Fir ◽  
Soil And Water Conservation ◽  
Masson Pine ◽  
Conifer Plantation ◽  
Coniferous Plantation ◽  
Soil And Water ◽  
The Ideal

Eighteen indices were selected to evaluate soil and water conservation capacities of four different mixtures of plantations using the Ideal Point Method. Results indicate that a broadleaf plantation of robur (Lithocarpus glabra) and Chinese guger tree (Schima superba) had the best conservation capacity, a mixed broadleaf plantation of sweetgum (Liquidambar formosana), Chinese gugertree and camphor tree (Cinnamomum camphora) was ranked second. A mixed broadleaf–conifer plantation of Chinese fir (Cunninghamia lanceolata), Masson pine (Pinus massoniana) and Chinese gugertree ranked third with a mixed coniferous plantation (Chinese fir and Masson pine) fourth. Under similar climates and topographical conditions, broadleaf plantations have better soil and water conservation capacities than conifer plantations. Sensitivity analysis showed that litter amounts and soil properties are the most important indicators of soil and water conservation capacities of plantations. Suitable measures such as deep tillage should be used to improve soil aggregation in different plantations.

scholarly journals The Effects of Iron Rust on the Ageing of Woods and Their Derived Pulp Paper

Polymers ◽  
2021 ◽  
Vol 13 (20) ◽  
pp. 3483
Author(s):  
Wael A. A. Abo Elgat ◽  
Ayman S. Taha ◽  
Mohamed Z. M. Salem ◽  
Yahia G. D. Fares ◽  
Martin Böhm ◽  
...  
Keyword(s):  
Wood Species ◽  
Lignin Content ◽  
Chemical Properties ◽  
Biological Properties ◽  
Accelerated Ageing ◽  
Pulp Yield ◽  
Cellulose Content ◽  
Fungal Activity ◽  
Pulp Paper ◽  
And Chemical Properties

The accelerated ageing of wood in terms of heating or iron rusting has a potential effect on the physio-mechanical, chemical and biological properties of wood. The effects of accelerated ageing on the mechanical, physical and fungal activity properties of some wood materials (Schinus terebinthifolius, Erythrina humeana, Tectona grandis, Pinus rigida and Juglans nigra) were studied after several cycles of heating and iron rusting. The fungal activity was assayed against the growth of Aspergillus terreus, Aspergillus niger, Fusarium culmorum and Stemphylium solani. In addition, the mechanical and optical properties of paper sheets produced from those wood pulps by means of Kraft cooking were evaluated. The mechanical and chemical properties of the studied wood species were affected significantly (p < 0.05) by the accelerated ageing, compared to control woods. With Fourier transform infrared (FTIR) spectroscopy, we detected an increase in the intensity of the spectra of the functional groups of cellulose in the heated samples, which indicates an increase in cellulose content and decrease in lignin content, compared to other chemical compounds. For pulp properties, woods treated by heating showed a decrease in the pulp yield. The highest significant values of tensile strength were observed in pulp paper produced from untreated, heated and iron-rusted P. rigida wood and they were 69.66, 65.66 and 68.33 N·m/g, respectively; we calculated the tear resistance from pulp paper of untreated P. rigida (8.68 mN·m2/g) and T. grandis (7.83 mN·m2/g) and rusted P. rigida (7.56 mN·m2/g) wood; we obtained the values of the burst strength of the pulp paper of untreated woods of P. rigida (8.19 kPa·m2/g) and T. grandis (7.49 kPa·m2/g), as well as the fold number of the pulp paper of untreated, heated and rusted woods from P. rigida, with values of 195.66, 186.33 and 185.66, respectively. After 14 days from the incubation, no fungal inhibition zones were observed. Accelerated ageing (heated or iron-rusted) produced significant effects on the mechanical and chemical properties of the studied wood species and affected the properties of the produced pulp paper.

scholarly journals Comparison of the mechanical characteristics of fibers and cell walls from moso bamboo and wood

BioResources ◽  
2017 ◽  
Vol 12 (4) ◽  
pp. 8230-8239
Author(s):  
Yanhui Huang ◽  
Benhua Fei
Keyword(s):  
Mechanical Properties ◽  
Cell Walls ◽  
Raw Materials ◽  
High Strength ◽  
Pinus Massoniana ◽  
Chinese Fir ◽  
Moso Bamboo ◽  
Wood Fibers ◽  
Masson Pine ◽  
Single Fibers

Bamboo and wood fibers are important raw materials for pulp and papermaking, as well as fiber-reinforced composites. The mechanical properties of single fibers and the cell walls of moso bamboo (Phyllostachys heterocycla), Masson pine (Pinus massoniana), and Chinese fir (Cunninghamia lanceolata) were tested via single fiber tensile test and nanoindentation; their fracture characteristics were also compared. The single fibers and cell walls of moso bamboo had superior mechanical properties compared with those of Masson pine and Chinese fir. The bamboo fibers exhibited high strength, high elasticity, and superior ductility. The results indicated that the differences between the mechanical properties of the fiber cells and cell walls of moso bamboo and those of wood were largely dependent upon cell shape and structure.

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