The Effect of Alkaline Treatment onto Physical, Thermal, Mechanical and Chemical Properties of Lemba Leaves Fibres as New Resources of Biomass

The main purpose of this paper is to investigate the effect of alkaline treatment on the physical, thermal, mechanical and chemical properties of pristine lemba leaves fibres (LeLeFs). LeLeFs were treated with 6, 8, and 10 wt% sodium hydroxide (NaOH) solution at room temperature for 24 h. In order to determine the functional group presence after the alkaline treatment, LeLeFs were analyzed using Fourier Transform Infrared (FTIR) Spectroscopy. The density of LeLeFs treated with 10 wt% NaOH solution recorded the highest density with 1.168 g/cm³. Morphology study showed that the diameter of fibre reduced with the increment of NaOH concentration. The removal of lignin and hemicellulose could be observed in the thermogravimetric analysis (TGA). Alkaline treatment enhanced the tensile properties of fibre and 10 wt% alkaline treated fibre resulted in the highest tensile strength, modulus and elongation of the fibre at 511.10 MPa, 11.76 GPa and 3.69% respectively. Chemical resistance analysis found that the treated fibre had better chemical resistance compared to untreated fibre. Therefore, it is substantiated that alkaline treatment affects the properties of LeLeF.

Conditioning effect on the mechanical and thermal properties of heat-treated oil palm empty fruit bunch/high-density polyethylene composite

Oil palm empty fruit bunch (EFB) is one of the potential natural fibre that can be used as an alternative to synthetic fibre. EFB was heat-treated at 180°C using vacuum oven for 1 h, extrusion compounded with high-density polyethylene at 10%, 20% and 30% weight fraction. The composites were injection moulded into dumb-bell (ASTM D-638) and bar-shaped specimens (ASTM E-23). The composites were exposed to different environments which are soil burial and indoor environment for 3 months. The effects of conditioning on mechanical and thermal properties were studied relative to the dry as moulded samples as a standard. It was found that the mechanical and thermal properties of composites under soil burial conditions were reduced. Tensile modulus of 30% untreated fibre loading reduced from 1.56 GPa for dry to 1.03 GPa for soil burial conditions, respectively. The same reduction was also found in the flexural modulus. However, the value of treated fibre composites was found slightly higher compared to untreated fibre composites. The treated fibre composites showed more resistance towards the environment condition. Composites made from heat-treated EFB show improved thermal stability, expected due to better compatibility between fibres and matrices, thus lowering the moisture intake, despite the conditions of the samples. However, indoor exposure has no significant effect on the thermal and mechanical properties of composites.

Incidence of mercerization treatment in the mechanical properties of bamboo fibre bundles "Guadua Angustifolia Kunth" from colombian origin

In this article, bamboo fibre bundles of "Guadua Angustifolia Kunth" specie were isolated from different locations of the basa zone: upper, middle and lower, through mechanical extraction method. The elastic modulus and the tensile strength were obtained with preliminary tensile tests. Applying the statistical analysis known as ANOVA, it was determined that the mechanical properties are similar in all the extension of the basa zone. From there, fibre bundles were extracted randomly, and a part of the fibre bundles was treated with NaOH (mercerization). Later, tensile tests with different calibration lengths were made for calculate the elastic modulus and the tensile strength of the treated and untreated fibre bundles. Best results belonged to the treated fibre bundles. A good correspondence between the results obtained in this work and the results reported in the literature was concluded.

Effects of Optimal Mordanting on the Bleaching and Spinning of Black Yak Fibres

In this paper, the orthogonal analysis method was adopted to analyse the optimal mordanting condition for the bleaching of black yak fibres. Without changing the subsequent oxidative/reducing bleaching technology, the optimal mordanting condition was as follows: per weight of water, the ferrous ion concentration is 16%, the sodium bisulfate concentration 3 g/l, the mordanting temperature 60 °C and the liquor pH value is 2. Based on the optimal mordanting condition, yak fibres were bleached. The properties of bleached and untreated yak fibres and yarns were tested by a fibre tensile tester, scanning electron microscopy, yarn strength tester, USTER Tester 5 and so on. By comparing the properties of untreated and bleached yak fibres and yarns, the effects of optimal mordanting on the bleaching and spinning of black yak fibres were presented. The results show that bleached yak fibres have poorer mechanical and morphology properties, and it is harder to felt for bleached fibres. For the spinning of 16.7 tex yarn, a complete condensing spinning system was adopted, and the performances of bleached fibre yarn decreased in the permissible range compared with the untreated fibre yarn.

Compatibility of Pretreated Coir Fibres (Cocos nuciferaL.) with Portland Cement to Produce Mineral Composites

The objectives of the present work were to evaluate the chemical compatibility between coir (Cocos nuciferaL.) and cement and to study treatment methods to improve this compatibility. In the inhibition test, cement hydration temperature evolution was measured in the absence and presence of untreated and treated coir fibres (cold water, hot water and NaOH), besides the addition of 4% of CaCl2. The chemical characterization of untreated and treated coir fibres was done by determining the content of extractives, lignin, and holocellulose. The inhibition test graded the untreated fibre as “extreme inhibition,” ratifying the need to provide it a treatment. Treatments done on coir fibres affected positively the compatibility between cement and fibre, reducing the inhibition. The treatments reduced the lignin coir fibres’ and extractives proportion, whose variation was significantly correlated with the reduction of the inhibitory index. These results indicate a possibility for future incorporation of these fibres into the production of mineral composites.

Improving Hygrothermal Performance in Epoxy-Biofibre Composites

Confocal microscopy and water diffusivity measurements were used to characterise the development of defects in biofibre-reinforced composite materials. Biofibres swelled more than the matrix when the specimen was immersed in water, but the associated distortion of the matrix rarely caused defects. The biofibres shrank faster than the matrix when the specimen was dried in air, causing debonding at the fibre-matrix interfaces and microcracks within the fibres. We started with coarse technical fibres from the leaves of harakeke (Phormium tenax), treated a portion with 1% NaOH, and pulped a portion at 170 °C. Water diffusivities for the corresponding composites increased over the first 3 wet-dry cycles, particularly for the composite made with untreated fibre, but were too small to be of concern for the composite made from pulped fibre.