Composites made from acetylated lignocellulosic fibers of different origin

Gomez-Bueso, J.; Westin, Mikael; Torgilsson, R.; Olesen, P. O.; Simonson, Rune

doi:10.1007/s001070050037

Cited by 8 publications

(4 citation statements)

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“…WA and TS after 2 and 24-h cold water soaking for 7% UF resin content were respectively 72, 79, 73 and 74% of the properties for 5% UF resin content. It is in agreement with the results of Suzuki et al (1976), Palardy et al (1989), Chow et al (1996), Gomez-Bueso et al (2000) and Halvarsson et al (2008). The properties of wood-based particleboard and medium density fiberboard are strongly dependant on the average density and to some extent on the amount of UF resin added (Suzuki and Kato 1989;Hague et al 1999;Wong et al 2000;Shi et al 2005).…”

Section: Resultssupporting

confidence: 87%

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Low resin medium density fiberboard made from chemical activated hardwoods fibers

Doosthoseini

Zarea-Hosseinabadi

Moradpour

2010

J Indian Acad Wood Sci

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This study was conducted to determine properties of medium density fiberboards (MDF) made from treated hardwoods fiber furnishes containing different amounts of two oxidizers, and the addition of limited amounts of synthetic resin. The effects of urea-formaldehyde (UF) resin content (two levels as 5 and 7%), oxidizer type (nitric acid and potassium dichromate), and oxidizer percent (three different levels as 4, 6, and 8%) on some static mechanical and physical properties of dry process interior grade MDF such as modulus of rupture (MOR), and modulus of elasticity (MOE) in bending in dry condition, compression-shear strength (CS sth ), water absorption (WA) and thickness swelling (TS) after 2-and 24-h soaking in cold water were investigated. Thirty six oxidative activated laboratory MDF panels were tested. Test results showed that increasing resin content significantly improved all physical and mechanical properties of treated MDF boards. Nitric acid had better mechanical and physical properties than potassium dichromate. Increasing oxidizer percent improved the physical and mechanical properties of MDF boards. Finally, three-way interaction of variables showed the best values for MOR, MOE and CS sth and WA and TS after 2-and 24-h soaking were discerned for T 6 treatment, i.e. the combination of 7% UF resin content together with 8% nitric acid. The properties for T 6 met the mechanical strength requirements of ANSI standard (ANSI A208. 2-2002) for 120-grade MDF.

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Section: Resultssupporting

confidence: 87%

“…The effect of this phenomenon on thickness swelling and moisture resistance is higher than that of on mechanical properties. Cross linking by synthetic resins in hardwood fibers, because of their lower lignin content, is more effective than that of in softwood fibers (Back 1987;Gomez-Bueso et al 2000;Halvarsson et al 2008).…”

Section: Resultsmentioning

confidence: 98%

Low resin medium density fiberboard made from chemical activated hardwoods fibers

Doosthoseini

Zarea-Hosseinabadi

Moradpour

2010

J Indian Acad Wood Sci

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“…In addition, they offer high performance at low cost due to excellent mechanical properties, especially when their low density and price are taken into account in comparison to, for example, E-glass fibres. The main drawbacks, compared with conventional inorganic fibres for composites, are (1) the large scatter in properties of wood fibres, explained by differences in fibre structure due to the overall environmental conditions during growth (Haygreen & Bowyer, 1982), and (2) the inherent susceptibility to moisture uptake and expansion of wood fibres, which negatively influences composite mechanical properties, such as stiffness and strength (Hua et al, 1987;Gomez-Bueso et al, 2000;Saha et al, 2000).…”

Section: Introductionmentioning

confidence: 99%

Ultrastructural features affecting mechanical properties of wood fibres

Neagu¹,

Gamstedt

Bardage

et al. 2006

Wood Material Science & Engineering

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The purpose of this review is to re-examine some of the existing knowledge on the ultrastructure of softwood fibres and modelling of the hygroelastic properties of these fibres. The motivation is that the ultrastructure of wood fibres has a strong influence on fibre properties such as stiffness and hygroexpansion. This structure Áproperty relationship can be modelled with, for instance, composite mechanics to assess the influence of ultrastructure on the fibre properties that in turn control the engineering properties of wood fibre composites and other wood-based materials. Comprehensive information about the ultrastructure is presented that can be useful in modelling the hygroelastic behaviour of wood fibres. Many attempts to model ultrastructure Áproperty relationships that have been carried out over the years are reviewed. Even though models suffer from limiting approximations at some level, they have been useful in revealing valuable insights that can help to clarify experimentally determined behaviour of wood fibres. Still, many modelling approaches in the literature are of limited applicability, not the least when it comes to geometry of the fibre structure. Therefore, an example of finite element modelling of geometrically well-characterized fibres is given. This approach is shown to be useful to asses the influence of the commonly neglected irregular shape on elastic behaviour and stress state in wood fibres. Comparison is also made with an analytical model which assumes cylindrical fibre shape. Predictions of the elastic properties made with analytical modelling of cylindrical fibres and with finite element modelling of geometrically characterized fibres are in concert, but the stress state and failure predictions only show qualitative similarity. It can be concluded that calculations on fibres with the irregular and more realistic geometry combined with experiments on single fibres are necessary for a better and more quantitative understanding of the hygroelastic behaviour and particularly failure of wood fibres. It is hoped that this paper can provide a foundation and an inspiration for modelling, in combination with experiments and microscopy, for better predictions of the mechanical behaviour of wood fibres and wood fibre composites.

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“…An important method of chemical modification is chemical coupling [1] which can be performed via fibre treatment with maleic anhydride-polypropylene copolymers for improving the interface between cellulose based fibres and polypropylene [12]. Other common chemical modification methods, applied for natural fibres are graft copolimerization [13], acetylation [14], alkalization [15] and silanization [16].…”

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confidence: 99%

The chemically treated hemp fibres to reinforce polymers

Kaczmar¹,

Pach²,

Burgstaller³

2011

Polimery

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The chemically treated hemp fibres to reinforce polymers Summary-The effect of different chemical treatments of hemp fibres, carried out by alkali treatment, acetylation and modification with maleic anhydride, on their physical, thermal and chemical properties as well as their surface characteristic was discussed in this paper. The morphology of the fibres was investigated by SEM. Thermal properties were investigated by TGA and DTA methods and the chemical composition of fibres by FT-IR spectroscopy. Chemical modifications resulted in the lowered content of lignin, pectin and hemicellulose, what is especially observable with mercerised fibres. Another effect of the chemical treatment applied is related to the removal of waxy substances from the surface, which was indirectly ascertained by SEM observation, which revealed a relatively smooth hemp fibres surface. TGA results showed that the applied chemical fibre treatment resulted in the lowered thermal degradation of the treated fibres, after the removal of non-cellulose components, especially lignin.

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Composites made from acetylated lignocellulosic fibers of different origin

Cited by 8 publications

References 0 publications

Low resin medium density fiberboard made from chemical activated hardwoods fibers

Low resin medium density fiberboard made from chemical activated hardwoods fibers

Ultrastructural features affecting mechanical properties of wood fibres

The chemically treated hemp fibres to reinforce polymers

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