Fabrication and Mechanical Performance of Non-Crimp Unidirectional Jute-Yarn Preform-Based Composites.

Yeasin Ali,Atik Faisal,Forkan Sarker,Abu Saifullah,Hom N Dhakal,Shah Alimuzzaman

doi:10.3390/molecules26216664

Abstract

This work developed novel jute-yarn, non-crimp, unidirectional (UD) preforms and their composites, with three different types of warp jute yarns of varying linear densities and twists in the dry UD preforms, in order to present a possible solution to the detrimental effects of higher yarn twists and crimp at the warp–weft yarn interlacements of traditional, woven, preform-based composites on their mechanical properties. In the developed UD preforms, warp jute yarns were placed in parallel by using a wooden picture-frame pin board, with the minimal number of glass weft yarns to avoid crimp at the warp–weft yarns interlacements, which can significantly enhance the load-bearing ability of UD composites compared to traditional, woven, preform composites. It was found that an optimal combination of jute warp yarn linear densities and twists in the UD preforms is important to achieve the best possible mechanical properties of newly developed UD composites, because it encourages a proper polymer-matrix impregnation on jute fibres, leading to excellent fibre–matrix interface bonding. Composites made from the 25 lb/spindle jute warp yarn linear density (UD25) exhibited higher tensile and flexural properties than other UD composites (UD20, UD30). All the UD composites showed a much better performance compared to the traditional woven preform composites (W20), which were obviously related to the higher crimp and yarn interlacements, less load-carrying capacity, and poor fiber–matrix interfaces of W20 composites. UD25 composites exhibited a significant enhancement in tensile modulus by ~232% and strength by ~146%; flexural modulus by 138.5% and strength by 145% compared to W20 composites. This reveals that newly developed, non-crimp, UD preform composites can effectively replace the traditional woven composites in lightweight, load-bearing, complex-shaped composite applications, and hence, this warrants further investigations of the developed composites, especially on long-term and dynamic-loading mechanical characterizations.

Highlights

The use of natural fibres in various structural and nonstructural composite applications is becoming a compulsory alternative to their synthetic counterparts because of natural fibres’ biodegradability and enormous environmental benefits
Both of these values of the jute yarns increased with the increase in yarn counts and these variations resulted in differences in the thicknesses and area densities of the developed UD20, UD25, UD30 preforms, since the same type of glass weft yarns with a constant 20 mm weft yarn-insertion spacing distance were used in these preforms
UD20 preform displayed the lowest values of thickness and area density, which was due to the compactness of jute yarns, after imparting higher amount of twist in the yarns, whereas with the increase in linear densities, the amount of imparted twists in the yarns were reduced which increased the loose appearance of the fibres in the respective jute yarns used in UD25 and UD30 preforms

Summary

Introduction

The use of natural fibres in various structural and nonstructural composite applications is becoming a compulsory alternative to their synthetic counterparts because of natural fibres’ biodegradability and enormous environmental benefits. Fibre-reinforced composite manufacturers have been trying to use natural dry-fibre preforms in structural composite applications, wherein the jute yarns can be utilized in a better way and can significantly increase the mechanical performance of the composites. Khondker et al [20] used a pinboard technique to produce a yarn-based, unidirectional (UD) fibre sheet These preforms were further impregnated and compressed in order to manufacture composites, but these preforms were only used in manufacturing premoulded composites. Shah et al [18] recently developed a continuous yarn-based mat by using a drum-winding technique for fibre collection, and used a cellulose-based binder to hold the fibres in a parallel direction This preform may tear off due to the low binding force between the cellulose binder and the jute fibre. The major drawback of the UD preforms of fibres and yarns is the lack of draping ability, and as a result of this, they can be torn off very in the presence of a little shear force during manufacturing of 3D composite structures based on these preforms

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Conclusion