**Introduction**

Among plant fibres, flax (*Linum Usitatissimum* L.) and hemp (*Cannabis Sativa*) fibres are now the two most-produced bast fibres in Europe [1]. Due to their properties, such as important environmental advantages, good specific mechanical properties, and often a viable cost [1], these fibres have emerged as an alternative to synthetic fibres, and the use of plant fibre composites (PFCs) has become a market reality [2–4]. Despite numerous similarities (cell wall, thicknesses, and numbers of layers/sub-layers, biochemical composition, cellulose microfibril angle, MFA), these two bast fibres generally exhibit differences in their tensile properties and their global tensile behaviour. Flax fibres generally have slightly better tensile properties than hemp fibres, especially in terms of tensile strength and stiffness; on the other hand, they reach a lower tensile strain at failure than hemp [5]. If a lot of studies are conducted at the scale of fibres to explain these differences [1,5–7], few papers are dedicated to the development of hemp-continuous fabrics used as reinforcement of composite samples [4,8,9]. This deficit for hemp could be attributed to technological barriers, such as fibre separation and the alignment of fibres throughout the transformation process and consequently the unavailability of these products on an industrial scale [10]. Hemp fibres are naturally discontinuous; therefore, hemp reinforcements have so far been based on twisted yarns of staple fibres by means of long-staple spinning techniques, mainly ring spinning. However, the high twist level in the yarns leads to fibre misalignment in composite materials and thus reduced stiffness. Furthermore, the high twist level compacts the yarn section and reduces the inter-fibre gaps, making it very difficult for the resin to penetrate inside the yarn structure [11]. Therefore, the use of very low twisted yarns is advised for composite application [12,13]. However, a low twist implies poor inter-fibre cohesion, and the yarn loses its otherwise good weaveability properties which are due to good tenacity and low hairiness.

Along with this fibrous reinforcement, the challenge is to identify new combinations of raw materials for the production of green composites whose performance is good enough to propose their use in suitable applications. Among the various bio-based thermoplastic resins, polyamide 11 (PA11) is a semi-crystalline bio-polyamide produced using 11-aminoundecanoic acid derived from castor oil and has gained a special industrial interest due to a good combination of mechanical properties and chemical resistance [14]. In particular, PA11 exhibits good toughness, compared to other bio-based thermoplastic resins, such as, polylactic acid (PLA), which is often proposed as a matrix for bio-composites [15,16]. The natural fibre/PA11 combination has been used to study the performance of bio-composites. Haddou et al. [17] associated long bamboo fibres with PA11 films to analyse the tensile behaviour. Gourrier et al. [18] studied the tensile, impact, and thermal properties of unidirectional flax tape with PA11 films. In these studies, composites were made by film stacking, but other processes offer a route for efficient manufacturing of thermoplastic composites due to the reduced flow distance of resin in reinforcement to optimise impregnation. Awais et al. [19] compared tensile, flexural and impact behaviour of commingled fabrics (woven and knitted) based on jute/flax/hemp fibres with PP yarns. To improve the impregnation of thermoplastic resin into fibre yarns, Kobayashi et al. [20] used the micro-braiding method to mix hemp roving and PLA multifilament in the yarns. These micro-braided yarns were placed in a pre-heated moulding die for consolidation by compression moulding to produce composite specimens. Zhai et al. [21] compared yarn morphologies, structures, mechanical tensile properties, and braidabilities of commingled flax/PP yarns obtained by micro-braiding or wrapping methods. In the wrapping process [22,23], a thermoplastic multifilament is wrapped around hemp roving, resulting in increased inter-fibre friction and improved yarn cohesion. This manufacturing process was successfully used by Corbin et al. [8] to produce a commingled yarn based on hemp roving and PA12 multifilament and associated woven fabrics and composite samples. In all of these studies, although the mechanical and thermal properties of thermoplastic polymers are described, as in Di Lorenzo et al. [24], few papers [25] deal with the identification of the thermomechanical properties of commingled yarns, which can be essential to improve parameters of impregnation during the thermocompression process. This paper deals with hemp roving and PA11 multifilament and describes the wrapping process, and how the hybrid yarns are used to weave fabrics. Composite samples reinforced by these fabrics were manufactured by thermocompression. The tensile properties of these commingled yarns were studied according to temperature and strain rates, and the mechanical properties of the woven fabrics and the composite samples were identified.

#### **2. Materials and Methods**
