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

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

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

Materials produced from plant biomass: part II: evaluation of crystallinity and degradation kinetics of cellulose

In this study Eucalyptus grandis (CEG) and Pinus taeda (CPT) cellulose fibers obtained from kraft and sulfite pulping process, respectively, were characterized using Fourier transform infrared (FTIR) spectroscopy and thermogravimetry (TGA). The degradation kinetic parameters were determined by TGA using Coats and Redfern method. FTIR results showed that CPT presented a more ordered structure with higher crystallinity than CEG. Thermogravimetric results showed that CPT had a higher thermal stability than CEG. The kinetic results revel that for CEG the degradation mechanism occurs mainly by random nucleation, although phase boundary controlled reactions also occurs while for CPT the degradation process is more related with phase boundary controlled reactions. Results demonstrated that differences between thermal stability and degradation mechanisms might be associated with differences in the cellulose crystalline structure probably caused by different pulping processes used for obtaining the cellulose fibers