Stinging nettle (Urtica dioica L.) has been observed to grow spontaneously on metal-contaminated soils marginalised by heavy industrial use, thereby presenting an opportunity for the economic utilisation of such lands. This study explores the potential of nettle as a fibre crop by producing short fibre-reinforced polylactic acid (PLA) composites through compounding and injection moulding. Whole stem segments from three nettle clones (B13, L18, and Roville), along with separated fibre bundles from the L18 clone, were processed. The fibre bundles were separated using a roller breaker unit and a hammer mill. From separation with the hammer mill, not only cleaned fibre bundles but also the uncleaned fibre-shive mixture and the undersieve fraction were processed. The Young's modulus of all composites exceeded that of unreinforced PLA, with mean values ranging from 5.7 to 8.1 GPa. However, the tensile strength of most composites was lower than that of pure PLA, except for the two composites reinforced with cleaned fibre bundles. Of these two, the reinforcement with fibre bundles from separation with the hammer mill led to superior mechanical properties, with a higher Young's modulus (8.1 GPa) and tensile strength (61.8 MPa) compared to those separated using the breaking unit (7.2 GPa and 55.9 MPa). This enhancement is hypothesised to result from reduced fibre damage and lower fibre bundle thickness. The findings suggest that nettle cultivation on marginal lands could be a viable option for producing short-fibre composites, thereby offering a sustainable use of these otherwise underutilised areas.

Biocomposite sheets were created by blending taro pulp with rice straw, pineapple fibre, guar gum, and corn starch. The optimal composition, comprising 90 % taro pulp and 10 % corn starch, demonstrated impressive mechanical properties, including a tensile strength of 61.42 MPa, bursting strength of 13.19 kg/cm2, a contact angle of 63.4 degrees, and water uptake of 82.33 %. To understand whether these qualities can be improved by coating with chitosan, silk fibroin, or combinations of both, coated samples were also studied. Chitosan coating displayed a tensile strength of 26.79 MPa, while fibroin coating further reduced it to 15.87 MPa. Notably, a 50:50 chitosanfibroin blend increased the contact angle to 117.8 degrees, reducing water uptake to 49.67 % and water vapor transmission rate to 4.73 %, compared to 46.15 % and 3.96 % for pure fibroin coating. Analysis revealed similar spectra among coatings, indicating analogous functional groups. XRD showed a crystalline cellulose I structure with crystallinity indices of 71.96-74.18 %. DSC displayed transitions near 190-240 degrees C, while TGA showed two- stage degradation with T5 at 130-180 degrees C, T10 at 244-264 degrees C, and T50 at 325-336 degrees C. SEM confirmed surface modifications induced by coatings. Combinations with higher fibroin content exhibited reduced water uptake and water vapor transmission rates compared to pure chitosan due to differences in chemical composition. While chitosan enhanced tensile strength, fibroin had a mitigating effect. Although not fully biodegradable, the coated sheets showed varying degrees of biodegradability under soil burial conditions for 60 days. These findings highlight the tunable properties of biocomposite sheets through composition and coatings, promising for packaging applications.

The interest in natural fibres in non - textile applications has increased as a result of the search for new renewable materials. Especially attractive for environmental safety demands are biodegradable and renewable fibres such as lignocellulose fibres and biopolymers such as PLA. The analysis of their biodegradation is often taken as a standard measure for environmentally friendly textile materials. Therefore, the aim of this paper is to investigate the biodegradation properties of Jute and PLA fibres by soil burial test. The fibres were exposed to the farmland soil for 11 days. The efficiency of the biodegradability was determined by comparison of mass loss, mechanical properties (finesses and tenacity) and morphological analysis by SEM microscope. With the purpose of a better understanding of biodegradation, the number of total fungi and bacteria in the soil is also determined.

Geotextiles are widely being used for different soil engineering applications such as filtration, separation, drainage, reinforcement and erosion control. Synthetic geotextiles are mainly produced from the petroleum-derived polymeric materials. The environmental awareness and concern towards sustainability necessitated the application of a more sustainable alternative with natural fibre-based geosynthetics. In this paper, the physical and mechanical properties of five different natural fibres, namely abaca, coir, jute, pineapple and sisal fibres, which could be a suitable candidate for geotextile applications have been analysed and compared. Out of the five different types of the fibres analysed in the present study, the highest average diameter, density and flexural rigidity were found to be for coir and the lowest were found to be for pineapple. It was observed that all the five types of the fibres have the potential for soil reinforcement applications. The unconfined compressive strength of the unreinforced clay was increased by 2, 3.3, 4. 4.1 and 5 times, when reinforced with abaca, coir, pineapple, sisal and jute fibres, respectively. However, jute fibres have low rigidity. The present study concluded that these natural fibres can perform effectively as a raw material for geotextiles. Pineapple fibre absorbs high amount of water and hence may degrade faster comparing to other natural fibres. The fibres which contain high proportion of cellulose possess high tensile strength. For coir fibres, due to the presence of high amount of lignin the life is comparatively high. Thus, blending of the fibres in suitable proportions can complement each other and can lead to the production of better geotextile materials in various applications. Considering the durability, strength and compatibility in blending and spinning, an attempt was made in the present study to develop woven geotextiles from 50% coir:50% sisal blended yarns which are found to be superior in functional characteristics.

Plastic pots used in horticultural nurseries generate substantial waste, causing environmental pollution. This study aimed to develop biodegradable composites from banana pseudo-stem reinforced with agricultural residues like pineapple leaves, taro and water hyacinth as eco-friendly substitutes. The aim of this study is to develop optimised banana biocomposite formulations with suitable reinforcements that balance mechanical durability, biodegradation, and seedling growth promotion properties to serve as viable eco-friendly alternatives to plastic seedling pots. This study was carried out by fabricating banana fibre mats through pulping, drying and hot pressing. Composite sheets were reinforced with 50 % pineapple, taro or water hyacinth fibres. The mechanical properties (tensile, yield strength, elongation, bursting strength), hydrophilicity (contact angle, water absorption), biodegradability (soil burial test), and seedling growth promotion were evaluated through appropriate testing methods. The results show that banana-taro composites exhibited suitable tensile strength (25 MPa), elongation (27 %), water uptake (41 %) and 82 % biodegradation in 60 days. It was observed that biodegradable seedling trays fabricated from banana-taro composite showed 95 % tomato seed germination and a 125 cm plant height increase in 30 days, superior to plastic trays. The finding shows that the study demonstrates the potential of banana-taro biocomposites as alternatives to plastic nursery pots, enabling healthy seedling growth while eliminating plastic waste pollution through biodegradation.

This study assesses the usability of natural materials available in Australia's remote communities for making fibre-reinforced mudbricks. The present construction cost for housing in remote areas is too high to maintain the level of housing required for the remote Australian population. As this includes mostly First Nations communities, more culturally appropriate housing materials and construction methods are being considered. This study looks at mudbricks made from laterite soil reinforced by spinifex fibre, both available in abundance in remote communities. Hence, this material is more acceptable to communities as it is more sustainable, and the construction methods are more suited for First Nations engagement. Various mixes were tested for compressive strength and erosion resistance. Results suggest that spinifex can significantly improve compressive strength and reduce erosion effects; however, spinifex showed adverse effects at the early stage of the spray test. The results satisfy the minimum strength and erosion resistance requirements for construction and suggest that spinifex-reinforced mudbricks could potentially be considered as an alternative material in remote housing.

The present investigation evaluates the mechanical, thermal, morphological, and crystalline behaviour of green composite reinforced with bamboo fibre under recycling and various environmental conditions. The short bamboo fibre was chemically modified at an optimum condition by treating the fibre for 4 h using sodium hydroxide (2% w/v) to produce a sustainable bamboo fibre (BF)/polylactic acid (PLA) composite through injection moulding. The optimum injection conditions considered to develop BF/PLA composite were a melting temperature of 165 degrees C, injection speed of 60 mm/s, and injection pressure of 90 bars. The fibre length and loading of 4 mm and 20% were considered to fabricate the BF/PLA green composite. The developed BF/PLA composites were exposed to different environmental conditions like water, soil, refrigerator, and room temperature for four weeks. The fabricated BF/PLA green composite specimens were recycled five times by implementing the manual mechanical cutting process. The impact of various environmental conditions and recycling on the mechanical properties was systematically monitored. The morphology of the fractured recycled specimens and specimens exposed to different environmental conditions were also examined using a scanning electron microscope (SEM). The thermo gravimetric analysis (TGA) was performed on the recycled BF/PLA specimens to investigate the thermal degradation behaviour of the developed composites. The crystalline behaviour of the BF/PLA composite exposed to different environmental conditions and recycled samples was also analysed by using X-ray diffraction (XRD). The maximum water absorption and thickness of swelling of the developed composite were observed at 6.49% and 5.56% when compared to the dry BF/PLA specimens. The mechanical behaviour of the BF/PLA green composite was superior in room temperature conditions followed by refrigerating, soil burial, and water immersion conditions. The maximum degradation temperature of non-recycled and after the fifth recycled BF/PLA composite was perceived at 348 degrees C and 329 degrees C. The deterioration in PLA and BF was observed due to the thermo-mechanical recycling. The degree of crystallinity of the unexposed sample was observed as 57.75% with a semi-crystalline nature. The crystallinity of BF/PLA composite was changed to amorphous while exposed to water, soil, refrigerator, and room temperature with a degree of crystallinity of 9.41%, 18.62%, 31.62% and 37.93%. Meanwhile, the fifth recycled BF/PLA composite exhibited a degree of crystallinity of 12.71%.

The interest in earth construction is growing increasingly as society becomes more aware of the importance of sustainable building. A considerable number of investigations have been devoted to studying the mechanical properties of compressed earth blocks (CEBs). However, most of these studies were conducted in laboratory settings. Little focus has been directed at studying the performance of CEBs that use on-site soil and other local materials to construct small-scale housing at the same location. A total of 120 CEBs were manufactured on-site from four block mixes: coarse soil with and without Phragmites Australis (Phragmites) and fine soil with and without Phragmites. By comparing the results achieved with minimum strength requirements from different building codes, the dry compressive strengths of all four block mixes were deemed adequate for single-storey structures. The addition of Phragmites caused a slight increase in the compressive strength and a slight decrease in the flexural strength of the CEBs. A formula to estimate the flexural strength of the blocks given the compressive strength is proposed based on a database of test results from the literature and this investigation's results. CEBs can create a sustainable building solution, especially in remote areas and Indigenous communities with limited access to conventional building materials.