Beating of hemp bast fibres: an examination of a hydro-mechanical treatment on chemical, structural, and nanomechanical property evolutions

Padovani, Justine; Legland, David; Pernes, Miguel; Gallos, Antoine; Thomachot-Schneider, Céline; Shah, Darshil U.; Bourmaud, Alain; Beaugrand, Johnny

doi:10.1007/s10570-019-02456-3

Cited by 16 publications

(16 citation statements)

References 75 publications

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“…Finally, other fibers, such as hemp, have a strong tendency to be divided or fibrillated during the composite production process. This phenomenon was highlighted in extruded or injected compounds [57][58][59]. Interestingly, the difference between CML and S 2 modulus is lower for hemp compared to other plants, and this might introduce a strong link between these two layers, whereby a weaker interface could possibly be identified at the intra S 2 layer level.…”

Section: Resultsmentioning

confidence: 94%

The Middle Lamella of Plant Fibers Used as Composite Reinforcement: Investigation by Atomic Force Microscopy

et al. 2020

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Today, plant fibers are considered as an important new renewable resource that can compete with some synthetic fibers, such as glass, in fiber-reinforced composites. In previous works, it was noted that the pectin-enriched middle lamella (ML) is a weak point in the fiber bundles for plant fiber-reinforced composites. ML is strongly bonded to the primary walls of the cells to form a complex layer called the compound middle lamella (CML). In a composite, cracks preferentially propagate along and through this layer when a mechanical loading is applied. In this work, middle lamellae of several plant fibers of different origin (flax, hemp, jute, kenaf, nettle, and date palm leaf sheath), among the most used for composite reinforcement, are investigated by atomic force microscopy (AFM). The peak-force quantitative nanomechanical property mapping (PF-QNM) mode is used in order to estimate the indentation modulus of this layer. AFM PF-QNM confirmed its potential and suitability to mechanically characterize and compare the stiffness of small areas at the micro and nanoscale level, such as plant cell walls and middle lamellae. Our results suggest that the mean indentation modulus of ML is in the range from 6 GPa (date palm leaf sheath) to 16 GPa (hemp), depending on the plant considered. Moreover, local cell-wall layer architectures were finely evidenced and described.Molecules 2020, 25, 632 2 of 17 be found in Wambua et al. [8]. The authors studied several poly-(propylene) composites reinforced with different plant fibers (sisal, kenaf, jute, hemp, and coir), and their results showed that coir fibers, extracted from seeds, have lower longitudinal mechanical properties than the others but, on the other hand, they exhibit a higher impact strength, which was also confirmed in Reference [9]. This result follows the functional evolution of the different kinds of cells in a plant; for example, bast fibers are responsible for the stiff structure of a plant and this specific role also explains their high mechanical performance.Every bast fiber has a similar (ultra)structural model even if they originate from different plants. An elementary fiber is a single cell, and several fibers are linked to each other to form a bundle of several dozens of single fibers having a multilayer structure, as illustrated in Figure 1a: (1) the lumen is the central hollow part of the cell and its shape and diameter vary with the maturity of the plant and the environmental conditions during growth; (2) the secondary cell wall is the thickest layer, divided into two to three sub-layers (S 1 , S 2 or G, and S 3 ) rich in cellulose where the thinner and not always visible S 3 can also be assimilated to unmatured Gn layer instead of a real S 3 [10]; (3) the primary cell wall is the external layer enriched in hemicelluloses, pectins, and lignin [11]. Between the fibers, there is another layer called middle lamella (ML), which cements the primary cell walls of adjacent cells together and is mainly composed of pectic polysaccharides, lignin, and a small amou...

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Section: Resultsmentioning

confidence: 94%

The Middle Lamella of Plant Fibers Used as Composite Reinforcement: Investigation by Atomic Force Microscopy

et al. 2020

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“…Amorphous hemicelluloses are largely responsible for the hydrophilic nature of flax fibres and their capacity to sorb water within the cell walls [36]. The presence of hysteresis on the sorption-desorption curves indicates the presence of mesopores in the structure of the fibre [37]. Indeed, flax fibres have a porous structure with many exchange surfaces.…”

Section: Discussionmentioning

confidence: 99%

Fibre Individualisation and Mechanical Properties of a Flax-PLA Non-Woven Composite Following Physical Pre-Treatments

et al. 2021

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Pre-treatments for plant fibres are very popular for increasing the fineness of bundles, promoting individualisation of fibres, modifying the fibre-matrix interface or reducing water uptake. Most pre-treatments are based on the use of chemicals and raise concerns about possible harmful effects on the environment. In this study, we used physical pre-treatments without the addition of chemical products. Flax tows were subjected to ultrasound and gamma irradiation to increase the number of elementary fibres. For gamma pre-treatments, a 20% increase in the number of elementary fibres was quantified. The biochemical composition of pre-treated flax tows exhibited a partial elimination of sugars related to pectin and hemicelluloses depending on the pre-treatment. The hygroscopic behaviour showed a comparable decreasing trend for water sorption-desorption hysteresis for both types of pre-treatment. Then, non-woven composites were produced from the pre-treated tows using poly-(lactid) (PLA) as a bio-based matrix. A moderate difference between the composite mechanical properties was generally demonstrated, with a significant increase in the stress at break observed for the case of ultrasound pre-treatment. Finally, an environmental analysis was carried out and discussed to quantitatively compare the different environmental impacts of the pre-treatments for composite applications; the environmental benefit of using gamma irradiation compared to ultrasound pre-treatment was demonstrated.

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“…43,136,137 Fiber modification method includes different types of physical and chemical treatments, while matrices are modified by various chemical treatments. Corona treatment, 138,139 plasma treatment, [140][141][142] ultraviolet (UV) treatment, [143][144][145] and fiber beating 146,147 are some of the frequently used physical treatments. Physical treatments are applied on fibers to enhance the bonding with matrices by changing their surface properties such as wettability, cleanliness, polarity, surface energy, and surface area.…”

Section: Factors Influencing the Mechanical Propertiesmentioning

confidence: 99%

Green composites from natural fibers and biopolymers: A review on processing, properties, and applications

Islam

Sarker

Rahman

et al. 2022

Journal of Reinforced Plastics and Composites

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At present, environmental sustainability is a big concern due to the limited resources and the adverse impacts of petroleum-based materials. Green composites (GCs) attracted intensive research interest for the last few decades from academicians, scientists, researchers, and practitioners both from the ecological and economic point of view and are presently being considered as one of the most promising research domains. Composites produced from renewable and/or natural resources thanks to their biodegradability and sustainability properties are envisaged as the next-generation materials to meet the growing demand worldwide. GCs are intensively investigated due to their multifunctional properties and utilization in a wide variety of fields including automobile, marine, aerospace, structural and infrastructural applications, packaging, electronics industry, sports, and biomedical applications. They also show potentials to replace the expensive as well as non-degradable petroleum-based composites. After the shelf life, it can be disposed of easily without harming the environment. The processing techniques, properties, and applications of green composites are comprehensively assessed in this review article. The feasibility of the naturally available fiber and polymers for green composites are also discussed highlighting the existing challenges with possible suggestions. It was intended to present a full overview of biodegradable polymer composites reinforced with natural fiber, as well as the necessary future directions for the concerned researchers.

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Beating of hemp bast fibres: an examination of a hydro-mechanical treatment on chemical, structural, and nanomechanical property evolutions

Cited by 16 publications

References 75 publications

The Middle Lamella of Plant Fibers Used as Composite Reinforcement: Investigation by Atomic Force Microscopy

The Middle Lamella of Plant Fibers Used as Composite Reinforcement: Investigation by Atomic Force Microscopy

Fibre Individualisation and Mechanical Properties of a Flax-PLA Non-Woven Composite Following Physical Pre-Treatments

Green composites from natural fibers and biopolymers: A review on processing, properties, and applications

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