Mechanical characteristics of groundnut shell particle reinforced polylactide nano fibre

ABSTRACT The PLA-groundnut shell solution is electrospun to produce nanocomposite fibre. The spinneret containing the composite solution was placed 24.7 cm away from the aluminium collector, tilted at an angle of 30 °, and the solution flow rate kept at 1 mL/min. Groundnut Shell particle (GSP) weight fraction used was varied from 3 - 8 wt. %. Particle reinforced nanofibres were formed on the collector from the composite solution at 26 kV. These nanofibres were subjected to tensile test and the result indicates that at 6 wt. % untreated GSP reinforced fibre possessed the best tensile stiffness of 24.62 MPa. This corresponds to 2.201 % increase in Modulus of Elasticity over the unreinforced PLA (1.07 MPa). The 7 wt. % treated GSP fibre showed the least stiffness (0.33 MPa), which is 69 % reduction over that of unreinforced fibre. PLA fibre reinforced with 5 wt. % untreated GSP displayed best blend of properties over the unreinforced with increase of 286 % (4.43 x 10-4 HB), 1,502 % (1.07 MPa), 286 % (0.22 MPa), 6.8 % (0.05 J) and 1,081 % (~ 0.15 MPa) in hardness, stiffness, UTS, energy at break and stress at break respectively. However, ductility decreased by ~33.3 % when compared to the unreinforced (18.27). The 5 wt. % untreated GSP PLA reinforced fibre showed the highest UTS (0.855 MPa). The micrographs showed beads on reinforced fibres, while the virgin PLA showed no beads

Manufacturing and properties of biobased thermoplastic composites from poly(lactid acid) and hazelnut shell wastes

This is the peer reviewed version of the following article: Balart, J.F., Garcia-Sanoguera, David, Balart, Rafael, Boronat, Teodomiro, Sanchez-Nacher, Lourdes. (2018). Manufacturing and properties of biobased thermoplastic composites from poly(lactid acid) and hazelnut shell wastes.Polymer Composites, 39, 3, 848-857. DOI: 10.1002/pc.24007 , which has been published in final form at [Link to final article using the DOI]. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Self-Archiving.[EN] Poly(lactic acid), PLA-based green composites were obtained with hazelnut shell flour (HSF) derived from the food industry thus leading to fully biodegradable materials with attracting properties. The hazelnut shell flour content varied in the 10-40wt% range. An increase in the degree of crystallinity with increasing HSF was detected, mainly due to the nucleating effect of lignocellulosic particles. The thermodimensional stability was noticeably improved with increasing HSF amount as evidenced by a remarkable decrease in the coefficient of thermal-linear expansion. Increasing HSF leads to stiffer materials as HSF particles act as interlock points that restrict polymer chain motion. Addition of hazelnut shell flour as filler in PLA-based green composites leads to fully biodegradable composites with balanced mechanical and thermal properties. Furthermore, it gives a solution to upgrade wastes from the hazelnut industry and contributes to lower the cost of PLA-based materials. POLYM. COMPOS., 39:848-857, 2018. (c) 2016 Society of Plastics EngineersContract grant sponsor: Ministerio de Economia y Competitividad-MINECO; contract grant number: MAT2014-59242-C2-1-R; contract grant sponsor: Conselleria d'Educacio, Cultura i Esport; contract grant number: GV/2014/008.Balart, J.; Garcia-Sanoguera, D.; Balart, R.; Boronat, T.; Sanchez-Nacher, L. (2018). Manufacturing and properties of biobased thermoplastic composites from poly(lactid acid) and hazelnut shell wastes. Polymer Composites. 39(3):848-857. doi:10.1002/pc.24007S84885739

Characterisation of mechanical and thermal properties in flax fabric reinforced geopolymer composites

This paper presents the mechanical and thermal properties of flax fabric reinforced fly ash based geopolymer composites. Geopolymer composites reinforced with 2.4, 3.0 and 4.1 wt% woven flax fabric in various layers were fabricated using a hand lay-up technique and tested for mechanical properties such as flexural strength, flexural modulus, compressive strength, hardness, and fracture toughness. All mechanical properties were improved by increasing the flax fibre contents, and showed superior mechanical properties over a pure geopolymer matrix. Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM) studies were carried out to evaluate the composition and fracture surfaces of geopolymer and geopolymer/flax composites. The thermal behaviour of composites was studied by thermogravimetric analysis (TGA) and the results showed significant degradation of flax fibres at 300 °C

Effect of different compatibilizers on injection-molded green composite pieces based on polylactide filled with almond shell flour

[EN] Green composites made of polylactide (PLA) filled with almond shell flour (ASF) at a constant weight content of 25¿wt.-% were manufactured by injection molding. In order to increase the interfacial adhesion between the biopolymer and the lignocellulosic fillers, three different compatibilizers were tested, namely multi-functional epoxy-based styrene-acrylic oligomer (ESAO), aromatic carbodiimide (AC), and maleinized linseed oil (MLO). The effect of each compatibilizer on the thermal, mechanical, and thermomechanical properties and water uptake of the injection-molded PLA/ASF pieces was analyzed. The obtained results indicated that all the here-studied compatibilizers had a positive influence on both the thermal stability and the mechanical and thermomechanical performance of the green composite pieces but low impact on their water uptake profile. In addition, the morphological analysis performed at the fracture surfaces of the green composite pieces revealed that the filler¿matrix gap was substantially reduced. Among the tested compatibilizers, ESAO and MLO yielded the highest performance in terms of mechanical strength and ductility, respectively. In the case of MLO, it also offers the advantage of being a plant-derived additive so that its application in green composites positively contributes to the development of sustainable polymer technologies.This research was supported by the Spanish Ministry of Economy and Competitiveness (MINECO) program number MAT2014-59242-C2-1-R and AGL2015-63855-C2-1-R and Generalitat Valenciana (GV) program number GV/2014/008. A. Carbonell-Verdu wants to thank Universitat Politecnica de Valencia (UPV) for his FPI grant. D. Garcia-Garcia wants to thank the Spanish Ministry of Education, Culture and Sports (MECD) for his FPU grant (FPU13/06011). L. Quiles-Carrillo also wants to thank GV for his FPI grant (ACT/2016/182) and the MECD for his FPU grant (FPU15/03812).Quiles-Carrillo, L.; Montanes, N.; Garcia-Garcia, D.; Carbonell-Verdu, A.; Balart, R.; Torres-Giner, S. (2018). Effect of different compatibilizers on injection-molded green composite pieces based on polylactide filled with almond shell flour. Composites Part B Engineering. 147:76-85. https://doi.org/10.1016/j.compositesb.2018.04.017S768514

A comprehensive review of techniques for natural fibers as reinforcement in composites::preparation, processing and characterization

Designing environmentally friendly materials from natural resources represents a great challenge in the last decade. However, the lack of fundamental knowledge in the processing of the raw materials to fabricate the composites structure is still a major challenge for potential applications.Natural fibers extracted from plants are receiving more attention from researchers, scientists and academics due to their use in polymer composites and also their environmentally friendly nature and sustainability. The natural fiber features depend on the preparation and processing of the fibers. Natural plant fibers are extracted either by mechanical retting, dew retting and/or water retting processes. The natural fibers characteristics could be improved by suitable chemicals and surface treatments. This survey proposes a detailed review of the different types of retting processes, chemical and surface treatments and characterization techniques for natural fibers. We summarize major findings from the literature and the treatment effects on the properties of the natural fibers are being highlighted

Preparation of cellulose nanofibers with hydrophobic surface characteristics.

The aim of this study was to develop cellulose nanofibers with hydrophobic surface characteristics using chemical modification. Kenaf fibers were modified using acetic anhydride and cellulose nanofibers were isolated from the acetylated kenaf using mechanical isolation methods. Fourier transform infrared spectroscopy (FTIR) indicated acetylation of the hydroxyl groups of cellulose. The study of the dispersion demonstrated that acetylated cellulose nanofibers formed stable, well-dispersed suspensions in both acetone and ethanol. The contact angle measurements showed that the surface characteristics of nanofibers were changed from hydrophilic to more hydrophobic when acetylated. The microscopy study showed that the acetylation caused a swelling of the kenaf fiber cell wall and that the diameters of isolated nanofibers were between 5 and 50 nm. X-ray analysis showed that the acetylation process reduced the crystallinity of the fibers, whereas mechanical isolation increased it. The method used provides a novel processing route for producing cellulose nanofibers with hydrophobic surfaces

Up-cycling of agave tequilana bagasse-fibres: A study on the effect of fibre-surface treatments on interfacial bonding and mechanical properties

The aim of this study was to assess the feasibility of upcycling fibre residues from the harvesting and production of tequila to green composites. Specifically, four different surface-modified natural fibres were assessed as raw material for green composite production. Before any surface treatment, the morphology and tensile properties of agave bagasse fibres from the tequila production batches were determined by optical and environmental scanning electron microscopy (ESEM) and single fibre tensile test, respectively. Further to this, agave fibres were exposed by immersion to four surface treatments including alkali, acetylation, enzymatic and silane treatments, in order to improve their morphology and compatibility with polylactic acid (PLA). The effects of these treatments on fibres’ morphology, mechanical properties (i.e. Youngs modulus and ultimate tensile strength), interfacial shear strength (IFSS), and water absorption were assessed. Overall, surface treatments showed improvements in agave bagasse fibre properties with the best results for alkali treated fibres with an ultimate tensile strength of 119.10 ​MPa, Young modulus of 3.05 ​GPa, and an IFSS of up to ~60% higher (5.21 ​MPa) to that performed by untreated samples. These tests allowed to identify alkali treatment as the most suitable for agave bagasse fibres. These results shed light on the interfacial interaction between agave bagasse fibres and PLA and the potential to up-cycle these residue agave fibres to manufacture PLA-based green composites