Flax/polypropylene composites for lightened structures: Multiscale analysis of process and fibre parameters

Doumbia, Awa S.; Castro, Mickaël; Jouannet, Denis; Kervoëlen, Antoine; Falher, Thierry; Cauret, Laurent; Bourmaud, Alain

doi:10.1016/j.matdes.2015.07.139

Cited by 49 publications

(38 citation statements)

References 40 publications

(56 reference statements)

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“…All the compositions show a behavior typical of non-Newtonian fluids, as their complex viscosity decreases with increasing shear rate, and this shear-thinning effect is stronger at high shear rates. As expected, the complex viscosity increases with increasing MC content, and this effect is more evident at lower shear stresses, as also reported in the literature for microfilled polymer composites [56,57], and observed for other thermoplastic polymers filled with paraffin microcapsules [27]. The neat PP presents a Newtonian plateau at low frequencies and a noticeable shear-thinning zone above approx.…”

Section: Physical Propertiessupporting

confidence: 87%

Melt-spun polypropylene filaments containing paraffin microcapsules for multifunctional hybrid yarns and smart thermoregulating thermoplastic composites

Fredi¹,

Bruenig²,

Vogel³

et al. 2019

Express Polym. Lett.

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The present work focuses on the development of polypropylene (PP) filaments containing paraffin microcapsules (MC), aimed at being incorporated in hybrid yarns to produce multifunctional thermoplastic laminates for thermal energy storage (TES). Benchmark experiments carried out on a small-scale melt compounder and piston-type melt spinning device resulted in the successful production of single filaments containing up to 30 wt% of MC, with diameters of 70-140 µm depending on the collection speed and a surface roughness that increases with the MC content. An increase in the MC fraction also determines a rise in the complex viscosity, but this effect is less evident at higher shear rates and likely almost negligible at the deformation rates typical of the spinning process. Although the MC have a considerable thermal stability, the compounded mixtures reported a sensible mass loss in isothermal thermogravimetric analysis (TGA) tests, which is linked to a not negligible MC damage during the compounding. Nevertheless, differential scanning calorimetry (DSC) on the spun filaments evidenced an increase in the phase change enthalpy with the MC content up to approx. 48 J/g, which is remarkably higher than that of similar systems reported in the literature. The elastic modulus and the properties at break decrease with an increase in the MC content, but the fiber strength is acceptable to produce a hybrid yarn and a thermoplastic laminate up to a MC fraction of 20 wt%.

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Section: Physical Propertiessupporting

confidence: 87%

Melt-spun polypropylene filaments containing paraffin microcapsules for multifunctional hybrid yarns and smart thermoregulating thermoplastic composites

Fredi¹,

Bruenig²,

Vogel³

et al. 2019

Express Polym. Lett.

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“…In Reference [52], opposite results were highlighted on flax bundles and significant cracks were visible after transverse tensile tests on the CML area. Indeed, the individualization of the fibers can be more or less pronounced, according to the process used to produce the composite material [18] and the scutching or hackling degree of the fibers [53] during the fiber extraction process. Consequently, all these factors can introduce significant changes in the mechanical performance of the final composite.…”

Section: Resultsmentioning

confidence: 99%

“…However, middle lamellae have a strong presence in plant fiber composite materials due to the specific arrangement of the fibers into bundles in planta. Their amount depends not only on retting and extraction conditions but also on the material processing conditions that influence the shear rate and the temperature experienced by the fibers during composite processing [16][17][18].…”

Section: Introductionmentioning

confidence: 99%

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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“…1) [26]. Exploring the performances of NFRP materials requires a multiscale method either for manufacturing process investigation [27] or for material characterization [28].…”

Section: Introductionmentioning

confidence: 99%

New Multiscale Approach for Machining Analysis of Natural Fiber ReinforcedBio-Composites

Chegdani

Mansori

2018

Journal of Manufacturing Science and Engineering

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is an open access repository that collects the work of Arts et Métiers ParisTech researchers and makes it freely available over the web where possible. This is an author-deposited version published in: https://sam.ensam.eu Handle ID ABSTRACTNatural fibers are emerging in many industrial sectors to perform eco-friendly materials such as bio-composites. However, machining of natural fiber reinforced polymer (NFRP)composites remains a complex manufacturing process and the machinability of industrial components underlies a specific approach that involves the multiscale structure of natural fibers. This paper presents first a multiscale method used in machinability rating of NFRP.The fundamentals of the multiscale method are hence applied to experimentally assess the machinability of a complete industrial bio-composite part. Results show that machining NFRP composites requires specific analysis scales that are intimately linked to the natural fibrous structure. The multiscale method can be used to improve the experimental design of NFRP machining and, above all, to determine the optimum process parameters that reflect the multiscale machining characteristics of these bio-based materials.

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Flax/polypropylene composites for lightened structures: Multiscale analysis of process and fibre parameters

Cited by 49 publications

References 40 publications

Melt-spun polypropylene filaments containing paraffin microcapsules for multifunctional hybrid yarns and smart thermoregulating thermoplastic composites

Melt-spun polypropylene filaments containing paraffin microcapsules for multifunctional hybrid yarns and smart thermoregulating thermoplastic composites

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

New Multiscale Approach for Machining Analysis of Natural Fiber ReinforcedBio-Composites

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