Thermoplasticization of Cellulose and Wood by Graft Copolymerization and Acylation

Shiraishi, Nobuo; Aoki, Takaaki; Norimoto, Misato; Okumura, Masakazu

doi:10.1021/bk-1982-0187.ch020

Cited by 15 publications

(11 citation statements)

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“…Preparing a wood thermoplastic by derivatization appears to be one of the most promising solutions. Wood flour has been reported to exhibit thermal fusibility after esterification treatment (Funakoshi et al 1979;Shiraishi et al 1982;Matsuda and Ueda 1985;Hon and Xing 1992). An example of film-forming that utilized thermal fusibility and esterification was also reported (Shiraishi et al 1982).…”

Section: Introductionmentioning

confidence: 99%

“…Wood flour has been reported to exhibit thermal fusibility after esterification treatment (Funakoshi et al 1979;Shiraishi et al 1982;Matsuda and Ueda 1985;Hon and Xing 1992). An example of film-forming that utilized thermal fusibility and esterification was also reported (Shiraishi et al 1982). Recently, several types of thermoplastic wood flour with ester substituents produced by efficient esterification processes of wood flour have been developed.…”

Section: Introductionmentioning

confidence: 99%

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Esterification of solid wood for plastic forming

Abe

Enomoto-Rogers

Seki

et al. 2020

BioRes

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Plastic formation from wood has recently attracted immense attention as a new method of producing three-dimensional materials by only one press. In this study, hydroxyl groups in (block-shaped) wood were replaced with ester groups to realize plastic formation. FT-IR measurements indicated that most of the hydroxyl groups in the block-shaped wood were replaced by ester groups after 4 h of treatment. The thermal properties of the esterified wood were investigated; the modulus of elasticity decreased remarkably when heated. Particularly, propionylated wood demonstrated a distinct softening point at relatively low temperatures, demonstrating its thermoplasticity. Additionally, the propionylated wood was stretched extensively by pressing with heat, showing its fluidity. Observation of the end grain of the esterified wood samples after pressing revealed that slippage occurred between the cells, resulting in the bulk flow of the wood. Finally, plastic formation using propionylated wood as the raw material was attempted, and a cup-shaped three-dimensional product was successfully formed. Contact angle measurements demonstrated that the cup-shaped molded product exhibited high water resistance. Thereafter, re-forming was attempted, using crushed fragments of the cup-shaped molded product, and a plate-shaped product was successfully re-formed. Thus, esterification is a promising method for increasing fluidity in solid wood, helping to enable its utilization in plastic forming.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Esterification of solid wood for plastic forming

Abe

Enomoto-Rogers

Seki

et al. 2020

BioRes

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“…Further, the chemical modification of wood to render it thermoplastic is also being explored as a method to limit the amount of petroleum-derived resin used in the composites. Esterification is a commonly used method for the thermoplasticization of wood [ 6 , 7 , 8 , 9 , 10 , 11 ]. On the other hand, as ether groups are generally more stable than the ester groups, etherification may be preferred as an alternative route to functionalize wood to render it thermoplastic.…”

Section: Introductionmentioning

confidence: 99%

Rapid Benzylation of Wood Powder without Heating

et al. 2021

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Converting wood waste into thermoplastic materials is an attractive means of increasing its utilization. A promising method for imparting thermoplasticity to wood is chemical modification, in which the hydroxyl groups in wood are substituted with benzyl groups. In the common method, wood powder is first treated with a highly concentrated aqueous NaOH solution, and then reacted with a benzylation reagent by heating for a long time under stirring. In this study, a 50% aqueous tetra-n-butylphosphonium hydroxide solution was used for the pretreatment of wood powder. This modified alkaline treatment enhanced the efficiency of the subsequent benzylation reaction, which could be conducted without heating over a shorter time. The effects of various conditions on the efficiency of the benzylation reaction were evaluated. Both the alkali pretreatment and the subsequent benzylation required only ~5–10 min of stirring without heating to obtain benzylated wood with a similar degree of benzylation as that achieved by the common method. The chemical structure of the benzylated wood powder was characterized by Fourier-transform infrared and solid-state NMR spectroscopies, and its thermal softening characteristics were evaluated by thermomechanical analysis. Finally, a translucent film could be obtained by hot-pressing the benzylated wood powder.

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“…The synthesis of wood thermoplastics through derivatization is considered a promising solution. Wood flour has been reported to exhibit thermal fusibility via esterification treatment [11][12][13][14]. Shiraishi et al succeeded in obtaining a film from an esterified wood powder [12].…”

Section: Introductionmentioning

confidence: 99%

Effect of the Propionylation Method on the Deformability under Thermal Pressure of Block-Shaped Wood

et al. 2021

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Converting wood waste into thermoplastic materials is an attractive means of increasing its utilization because complex three-dimensional molded products can easily be obtained by press molding wood with thermoplasticity. Chemical modification, especially esterification, is a promising method for imparting thermoplasticity to wood. In this study, we produced multiple propionylated wood specimens using several propionylation methods and elucidated the factors affecting the deformability of the wood. Regardless of the method, all of the propionylated wood samples showed deformability in the tangential direction. However, in the longitudinal direction, not only the degree of propionylation but also the propionylation method had a significant influence on the deformability. The flow in the tangential direction occurred under a relatively low pressure, whereas the flow in the longitudinal direction occurred under higher pressure. The chemical composition and motility of each sample were evaluated using solid-state NMR measurements. With some propionylation methods, decomposition of the cellulose main chain occurred during the reaction, which had a dominant effect on the deformability of the wood in the longitudinal direction. These results indicate that the deformability of wood can be controlled by the appropriate selection of a propionylation method and its treatment conditions.

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Thermoplasticization of Cellulose and Wood by Graft Copolymerization and Acylation

Cited by 15 publications

References 0 publications

Esterification of solid wood for plastic forming

Esterification of solid wood for plastic forming

Rapid Benzylation of Wood Powder without Heating

Effect of the Propionylation Method on the Deformability under Thermal Pressure of Block-Shaped Wood

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