Effects of Micro-Braiding and Co-Wrapping Techniques on Characteristics of Flax/Polypropylene-Based Hybrid Yarn: A Comparative Study

Abstract

Micro-braiding and co-wrapping techniques have been developed over a few decades and have made important contributions to biocomposites development. In this present study, a set of flax/polypropylene (PP) micro-braided and co-wrapped yarns was developed by varying different PP parameters (PP braiding angles and PP wrapping turns, respectively) to get different flax/PP mass ratios. The effects on textile and mechanical characteristics were studied thoroughly at the yarn scale, both dry- and thermo-state tensile tests were carried out, and tensile properties were compared before and after the braiding process to study the braidabilities. It was observed that PP braiding angles of micro-braided yarn influenced the frictional damage on surface treatment agent of flax roving, the cohesive effect between PP filaments/flax roving, and the PP cover factor; PP wrapping turns of co-wrapped yarn had a strong impact on the flax roving damage and the PP coverage, which further influenced the characteristics. Micro-braided yarn and co-wrapped yarn with the same flax/PP mass ratio were compared to evaluate the two different hybrid yarn production techniques; it was proven that micro-braided yarn presented better performance.

Effect of the cover factor on the tensile properties of multi-core flax/polypropylene micro-braided hybrid yarns for thermoplastic biocomposites

“…The thermo-state tensile tests were conducted by using a universal tensile tester MTS and in an isothermal oven. 9 To ensure an accurate fixed length of the specimen, the length was set as 150 mm considering the size of the oven. Preliminary experiments were conducted to confirm the thermo-conditions since the thermoplastic hybrid yarn tensile behavior is temperature- and extension velocity-dependent in the thermo-state; the viscosity of thermoplastic depends on the temperature, shear rate, and pressure.…”

“…In another case, which means the case of over-covered cannot be taken into account, equation (9) gives back negative values, since the braider mostly overlap or the effective braider radius changes.…”

“…Different techniques of natural fiber-based hybrid yarns applied by researchers, 4–8 such as co-wrapping, core spinning, commingling, and micro-braiding, have been resumed and compared in the previous study. 9 Among them, the micro-braided yarn (MBY) technique as a good choice was first proposed by Sakagushi et al in the year 2000. The technique was quite successful in braiding PA6 matrix filaments over glass core fiber, for UD composites application.…”

Influence of the Unit Cell Parameters on the Thermomechanical Non-Symmetric In-Plane Shear Behavior of 2D Biaxial Braided Preform for Thermoplastic Biocomposites

“…The raw material for 2D biaxial braided preform was the flax/PP micro-braided hybrid yarn which was described in a previous study [ 51 ]. The main properties of hybrid yarn and thermogravimetric analysis of raw materials (flax roving and PP filament) are given in Figure 5 .…”

Elaboration by Wrapping Process and Multiscale Characterisation of Thermoplastic Bio-Composite Based on Hemp/PA11 Constituents

“…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.…”