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

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.

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

Holzforschung ◽

10.1515/hf-2018-0190 ◽

2019 ◽

Vol 73 (10) ◽

pp. 957-965 ◽

Cited By ~ 1

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.

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

MATEC Web of Conferences ◽

10.1051/matecconf/201927501013 ◽

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%.

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Controlled ice nucleation under high voltage DC electrostatic field conditions

Food Research International ◽

10.1016/j.foodres.2009.03.015 ◽

2009 ◽

Vol 42 (7) ◽

pp. 879-884 ◽

Cited By ~ 75

Author(s):

Marta Orlowska ◽

Michel Havet ◽

Alain Le-Bail

Keyword(s):

High Voltage ◽

Electrostatic Field ◽

Ice Nucleation ◽

Field Conditions

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Influence of high voltage electrostatic field (HVEF) on bonding characteristics of Masson (Pinus massoniana Lamb.) veneer composites

European Journal of Wood and Wood Products ◽

10.1007/s00107-018-1360-6 ◽

2018 ◽

Vol 77 (1) ◽

pp. 105-114 ◽

Cited By ~ 8

Author(s):

Qian He ◽

Tianyi Zhan ◽

Zehui Ju ◽

Haiyang Zhang ◽

Lu Hong ◽

...

Keyword(s):

High Voltage ◽

Electrostatic Field ◽

Pinus Massoniana ◽

Pinus Massoniana Lamb ◽

Bonding Characteristics

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Enhancement of Wood Biological Resistance and Fire Retardant Properties after Laccase Assisted Enzymatic Grafting

Forests ◽

10.3390/f12081102 ◽

2021 ◽

Vol 12 (8) ◽

pp. 1102

Author(s):

Cristian Bolaño ◽

Sabrina Palanti ◽

Luigi Benni ◽

Diego Moldes

Keyword(s):

Silver Nanoparticles ◽

Flame Retardant ◽

Toxic Substance ◽

Treated Wood ◽

Fire Retardant ◽

Wood Preservative ◽

Decay Resistance ◽

Kraft Lignin ◽

Fire Retardant Properties ◽

Wood Surfaces

Several treatments of wood, based on laccase assisted grafting, were evaluated in this paper. Firstly, the efficacy of lignosulfonate and kraft lignin from Eucalyptus spp. as a wood preservative was assessed. Both ligno products were anchored to wood surfaces via laccase treatment in order to avoid leaching. Moreover, some of these wood preservative treatments were completed with the addition of silver nanoparticles. For comparison, a commercial product was also analyzed in terms of its fungal decay resistance during surface application, in accordance to use class 3, CEN EN 335. Secondly, the anchoring of a flame retardant based on tetrabromobisphenol-A (TBBPA) was attempted, to limit the dispersion of this toxic substance from treated wood. In both cases, kraft lignin and lignosulfonate showed an improvement in wood durability, even after leaching. However, the addition of silver nanoparticles did not improve the efficacy. On the other hand, the efficacy of TBBPA as a flame retardant was not improved by grafting it with laccase treatment or by adding O2, a co-factor of laccase.

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