Effect of various chemical treatments on the fibre structure and tensile properties of industrial hemp fibres

Natural fibres have excited growing attention in the last decade since they offer the potential to act as candidates substituting for man-made fibres as composite reinforcements. Their superiority over synthetic fibres is that they are environmentally friendly and biodegradable. Numerous industrial sectors are interested in such composites, including but to name a few the aeronautical and the automotive fields. However natural fibres tend to suffer from large variability in properties compared to the "traditional" man-made fibres, and the performance of their composites often does not conform to that theoretically predicted from single-fibre tests. This study investigates the properties of the single fibres. The mechanical properties of the fibres were correlated to their microstructure. There are factors that were found to contribute to the reported variability, some of which are inherent in the fibres and some are related to testing parameters.

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“…Sawpan et al [28] also observed the kinks in the structure Adhesive covering the fibre (the pulled-out region)…”

Section: Introductionmentioning

confidence: 97%

Looking for Links between Natural Fibres’ Structures and Their Physical Properties

Everitt

Aboulkhair

Clifford

2013

Conference Papers in Materials Science

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“…The size of fibers was sorted by sieve shaker using 30 (large fiber (LF)), 60 (middle fiber (MF)), and 80 (small fiber (SF)) mesh, respectively. Fibers were then cleaned by soaking in hot water at a temperature of 50°C for 30 min and then dried in the oven at 80°C for 48 h. 22 …”

Section: Preparation Of the Hwc Fibermentioning

confidence: 99%

Polypropylene/hemp woody core fiber composites: Morphology, mechanical, thermal properties, and water absorption behaviors

Ngaowthong

Rungsardthong

Siengchin

2016

Advances in Mechanical Engineering

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Natural fiber composites composed of polypropylene, maleic anhydride-graft-polypropylene, and hemp woody core fiber were produced by two-roll mill mixing. The hemp woody core fiber was treated by alkaline. The morphology of the polypropylene/hemp woody core fiber composites was studied by scanning electron microscopy technique. The mechanical and thermo-mechanical properties of the polypropylene/hemp woody core fiber composites were determined in tensile, flexural tests, and thermogravimetric analysis, respectively, and discussed. It was found that incorporation of hemp woody core fiber in polypropylene increased the tensile and flexural modulus. Note that the stiffness of short hemp woody core fiber/polypropylene composites was markedly improved. However, the flexural and impact strength of polypropylene/hemp woody core fiber composites was reduced compared to the neat polypropylene. Incorporation of hemp fiber increased the water uptake compared to the neat polypropylene. It was established that the Fick's law was fairly applicable to the water absorption results. The stiffness and thermogravimetric analysis behavior of the polypropylene/hemp woody core fiber composites were markedly affected by the surface treatments.

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“…After the lignin has been removed by alkali, hemicellulose depolymerization occurs; the reducing end-group of the hemicellulose chain is oxidized (Keller et al 2001;Sinha and Rout 2008;Sawpan et al 2011;Sharma et al 2011). Cellulose is easily hydrolyzed by acid and easily oxidized.…”

Section: Peer-reviewed Articlementioning

confidence: 99%

“…Wetting allows the hemp fiber to swell and become loose, which improves the penetration of scouring agents. Under alkaline conditions, lignin reacts with alkali, and the ether bonds present in the compounds of α-phenyl ether, α-alkyl ether, β-aryl ether, and aryl ether linked with lignin would be attacked by nucleophile of OH -and broken, In addition, the reaction degrades and dissolves large molecules such as lignin.After the lignin has been removed by alkali, hemicellulose depolymerization occurs; the reducing end-group of the hemicellulose chain is oxidized (Keller et al 2001;Sinha and Rout 2008;Sawpan et al 2011;Sharma et al 2011). Cellulose is easily hydrolyzed by acid and easily oxidized.…”

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confidence: 99%

An Efficient Method of Bio-Chemical Combined Treatment for Obtaining High-Quality Hemp Fiber

Fang

Chen

et al. 2017

BioResources

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This bio-chemical study focuses on obtaining high-quality hemp fiber. The effects of the structures and properties of hemp fibers in different treatment periods were studied. Moreover, the changes of the surface morphology, chemical composition, and breaking tenacity of hemp fibers were researched by scanning-electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR), fluorescence microscopy, and fiber tensile testing. The results showed that by virtue of the enzyme scouring process, alkali refining process, and bleaching process, the pectin, lignin, and hemicellulose and other impurities were removed. Through the single factor experiment, the optimal process conditions for the bio-chemical combination of the degumming process were obtained. These conditions included 10 g of dried hemp fibers, 15% (v/v) pectinase solution, a temperature of 50 °C, a duration of 120 min, pH 8.0 (phosphate buffer), a liquor ratio (w/v) of 1:10, and 0.0625 mol/L NaOH. In these conditions, the residual gum content and breaking tenacity were 4.8% and 49.8 cN/tex, respectively, indicating that the treated hemp fibers met the requirements of the spinning process.Keywords: Hemp; Degumming; Residual gum Contact information: School of Environmental Engineering, Wuhan Textile University, Wuhan, Hubei Province, 430073, China; *Corresponding author: honggao_chen@hotmail.com INTRODUCTIONHemp fibers have relatively low fineness and no scratchiness, which promotes their high hygroscopicity, gas permeability, and other excellent properties. In addition, these fibers are resistant to bacteria, mold, and ultraviolet rays, and they can be used in healthcare applications (Mohanty et al. 2002;Keller 2003;Khan et al. 2014). With the low content of tetrahydrocannabinol (THC < 0.3%) that has been achieved by breeding of hemp varieties (Lachenmeier et al. 2004), hemp has gradually come to the forefront of textile applications. The hemp fiber can be blended and spun with cotton, silk, wool, and other chemical fibers, and it can also be spun into mono-fibers. However, the phloem of hemp contains hemicellulose, lignin, pectin, wax, and other chemical impurities that must be removed from the fiber surface in a key process called degumming (George et al. 2015). Degumming has significant effects on spinning quality, fabric style, and comfort. There is a direct relationship between the degumming quality and fiber properties (Sreenath et al. 1996;Nair et al. 2015).Compared with ramie fiber, hemp fiber has higher hemicellulose and lignin contents, which directly affects its spinning performance. Commonly used degumming methods include chemical degumming (Di Candilo et al. 2000;Wang et al. 2003;Thomsen et al. 2006), physical degumming (Vignon et al. 1995Dupeyre and Vignon 1998;Guo and Zhao 2010), and biological degumming (Nykter et al. 2008). PEER-REVIEWED ARTICLEbioresources.com Fang et al. (2017). "Hemp fiber degumming," BioResources 12(1), 1566-1578. 1567Because the water resistance of hemp is very strong, the fiber is difficult to ferme...

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Effect of various chemical treatments on the fibre structure and tensile properties of industrial hemp fibres

Cited by 325 publications

References 30 publications

Looking for Links between Natural Fibres’ Structures and Their Physical Properties

Looking for Links between Natural Fibres’ Structures and Their Physical Properties

Polypropylene/hemp woody core fiber composites: Morphology, mechanical, thermal properties, and water absorption behaviors

An Efficient Method of Bio-Chemical Combined Treatment for Obtaining High-Quality Hemp Fiber

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