Structural colors are bright and possess a remarkable resistance to light exposure, humidity, and temperature such that they constitute an environmentally friendly alternative to chemical pigments. Unfortunately, upscaling the production of photonic structures obtained via conventional colloidal self-assembly is challenging because defects often occur during the assembly of larger structures. Moreover, the processing of materials exhibiting structural colors into intricate 3D structures remains challenging. To address these limitations, rigid photonic microparticles are formulated into an ink that can be 3D printed through direct ink writing (DIW) at room temperature to form intricate macroscopic structures possessing locally varying mechanical and optical properties. This is achieved by adding small amounts of soft microgels to the rigid photonic particles. To rigidify the granular structure, a percolating hydrogel network is formed that covalently connects the microgels. The mechanical properties of the resulting photonic granular materials can be adjusted with the composition and volume fraction of the microgels. The potential of this approach is demonstrated by 3D printing a centimeter-sized photonic butterfly and a temperature-responsive photonic material.

This paper presents a new design numerical tool for geosynthetic-reinforced soil embankments, used to mitigate rockfall risk in scenarios of large volumes, energies, and multiple block failures. The model can simulate both local block penetration into the uphill embankment face and extrusion mechanism frequently affecting the downhill face. The new model is based on an existing elastic-visco-plastic model, originally developed to simulate impacts of blocks on homogeneous granular strata. The model has been enhanced and modified by incorporating a plastic mechanism, accounting for the extrusion process potentially occurring within the embankment body. The model is initially described and then validated using available in situ real-scale test data; finally, the results of a parametric study, examining the influence of the main controlling parameters and the applicability of the tool for pre-design purposes, are illustrated.

Poly(butylene adipate-co-terephthalate) (PBAT) and graphene oxide (GO) nanocomposite films were prepared by extrusion to evaluate their potential as films for food packaging. The films were prepared with contents of 0.05, 0.1, and 0.25% in mass of GO by solid-solid deposition methodology. It was verified that GO did not modify the hydrophobicity and crystallinity degree of PBAT. The reduction of molecular weight due to GO incorporation was verified, and it could be the main reason for the observed decrease in tensile strength and increase in elongation. The nanofiller permitted ultraviolet blocking, thermal stability, and oxygen barrier improvements without compromising film visibility. Compared to the neat PBAT film, the oxygen permeability coefficient was reduced by 13.6% for PBAT/GO0.25. The elongation and tenacity were also improved by 90% and 33%, respectively, for the highest concentration of GO (0.25%). Besides, GO at 0.25% accelerated the mineralization rate of PBAT in soil, probably due to the lower molecular weight of nanocomposites in relation to the neat polymer. The preliminary information obtained in this work indicates that the level of PBAT hydrolytic degradation during the extrusion process was not high enough to avoid its application in food packaging because the obtained thermal, mechanical, and ultraviolet (UV) barriers still indicate an exciting balance of properties for this purpose, which can even be improved with future research.

This research investigated the production of biodegradable plastic films made from a blend of carrageenan and corn starch biopolymers. The procedure included producing bioplastic resin pellets using a single screw extrusion at a 110 degrees C temperature, followed by hot compression at a temperature of 160 degrees C to form a biodegradable plastic film. The project aimed to develop a continuous biodegradable plastic production method, particularly made from carrageenan, which is more adaptable for commercial-scale production. The carrageenan/corn starch films were prepared with various compositions, ranging from formulations dominated by carrageenan (56:14% w/w) to those dominated by corn starch (14:56% w/w), with the addition of a constant amount of glycerol (30% w/w) as a plasticizer. After the films were obtained, each of the samples was evaluated for their physico-mechanical properties, chemical structure, water sensitivity, and soil biodegradability. In general, an increase in corn starch content within the film matrix led to an enhancement of the overall properties of the resulting film. The film with the highest corn starch content exhibited tensile strength and elongation at break values that were 49% and 163% higher, respectively, compared to the film with the lowest corn starch content. Additionally, these samples demonstrated improved thermal stability, with a 12% increase in the thermal decomposition temperature, and enhanced barrier properties, as evidenced by a 6% reduction in water vapor permeability and a 72% decrease in water uptake. This is mainly due to the inherent molecular structure of corn starch, particularly due to its long straight-glucose chains. On the other hand, carrageenan increased the biodegradability rate of the films. These findings demonstrate the potential of carrageenan/corn starch blends as promising candidates for future packaging materials.

Melt-processed starch-based film formulations with market-competitive qualities and scalability for commercialization are developed in this study, unlike solvent casting, which has major technical and operational restrictions. First, a computational approach was utilized to understand the plasticization effect at molecular level and the same was validated with the experimental approach. The experimental process involved varying of glycerine content in the formulations (15-25 wt%) along with melt processing temperature (80 degrees C-140 degrees C), to deliver superior properties without the use of secondary fillers and additives. In comparison to other compositions, the starch-based system with 15 % glycerine and a processing temperature of 140 degrees C demonstrated the best properties in terms of mechanical (tensile strength: 20.5 MPa) and wettability (contact angle similar to 93.8 degrees). The thermal stability of films declined as the glycerine level was increased. It is noteworthy that the films underwent similar to 94 % weight loss within 30 days in soil compost admixture under ambient conditions. This study would facilitate future development of starch-based low-cost, high-value packaging products.

Aiming to address the problems of poor separation of peanuts and soil and severe damage of pods during peanut harvesting in saline soil, a peanut digging and harvesting machine was designed using extrusion shaking vibration and roller extrusion. Theoretical calculations determined the structural parameters of critical components. The law of motion of the seedling soil assemblage at the stage of separation and transportation was derived by analyzing the kinematic properties. The soil extrusion vibration crushing dispersion and sieving process was analyzed, and the factors affecting soil crushing and separation were determined by establishing the extrusion collision model. One-way and orthogonal tests used soil content, breakage, and loss rates as test indicators. The orthogonal test showed that the working parameters were as follows: working speed was 0.889 m/s, the inclination angle was 21.5 degrees, the working line speed of the sieve surface was 2.00 m/s and the roller gap of the roller squeezing device was 37 mm, the peanut harvesting rate of soil content was 1.36%, the breakage rate was 0.78%, and the loss rate was 1.15%. The paper references developing a peanut harvester for clay-heavy soil with soil separation performance improvement.

Non-degradable plastic mulch films used in agriculture are polluting the environment by leaving residues and microplastics in the soil. They are also difficult to recycle due to contamination during their use. Biodegradable mulch films are needed as alternatives so that they can be used effectively during the growing season and later be ploughed to be degraded in soil. However, market-available so-called biodegradable mulch films are very slow to degrade in the natural environment and thus do not fit with crop rotation demands or annual cultivation. In this study, we have developed mulch films from cotton gin trash (CGT) and/or gin motes (GM) in combination with biodegradable polycaprolactone and demonstrated their effectiveness over 3 months in outdoor conditions. Both the stability and degradation behaviours of mulch film samples were observed when they were placed on top of the soil and buried in the soil, respectively. Pesticide residue analysis also was carried out on CGT powder to identify and quantify individual pesticides against a matrix of known pesticides. The mulch films prepared in this study showed comparable and stable mechanical properties compared to commercial biodegradable mulch film, though were much quicker to degrade when buried in the soil. No pesticides were detected in the CGT samples. The films produced were vapour-permeable and may be useful in practical agricultural settings by being able to maintain consistent soil moisture and allowing precipitation to penetrate gradually. The lab-scale productioncost for the film was 98.8 AUD/kg, which could be lowered by integrating a continuous film line in large-scale production.

Melt blending is a reliable and well-demonstrated strategy for improving the mechanical, thermal, rheological, and surface properties of biopolymers. Poly(hydroxy-3-butyrate-co-3-hydroxyvalerate) (PHBV) and poly(butylene adipate-co-terephthalate) (PBAT) are the two popular choices for blending polymers due to their diverse properties and complementary soil biodegradable behaviour. Due to their immiscibility, however, blending with the help of processing additives is necessary to reap the most significant benefits from this process and to avoid immiscibility issues. This study utilized the additives (peroxides and epoxy-based chain extender) to compatibilize the biodegradable polymers PHBV and PBAT in a 60:40 blending ratio. The tensile strength and Young's modulus of the PHBV/PBAT(60/40) blend were improved by 32% and 64%, respectively, after adding a combination of peroxide (0.02 phr) and chain extender (0.3 phr) due to the formation of a complex network structure with increased chain length. The positive effect of an additive addition was also reflected by a 30 degrees C increment in heat deflection temperature of biodegradable blend due to its high modulus value as supported by mechanical properties. The combined action of a peroxide and chain extender demonstrated a significantly higher complex viscosity of the PHBV/PBAT(60/40) blend due to the formation of a crosslinked polymer network as analyzed by rheological analysis. Our research demonstrated the effect of additives and their combined impact on analytical properties of PHBV/PBAT(60/40) blend to guide future work in improving their candidature to serve as a drop-in solution in replacing non-biodegradable petro-based plastic products.

The development of efficient and sustainable composites remains a primary objective of both research and industry. In this study, the use of biochar, an eco-friendly reinforcing material, in additive manufacturing (AM) is investigated. A high-density Polyethylene (HDPE) thermoplastic was used as the matrix, and the material extrusion (MEX) technique was applied for composite production. Biochar was produced from olive tree prunings via conventional pyrolysis at 500 degrees C. Composite samples were created using biochar loadings in the range of 2.0-10.0 wt. %. The 3D-printed samples were mechanically tested in accordance with international standards. Thermogravimetric analysis (TGA) and Raman spectroscopy were used to evaluate the thermal and structural properties of the composites. Scanning electron microscopy was used to examine the fractographic and morphological characteristics of the materials. The electrical/dielectric properties of HDPE/biochar composites were studied over a broad frequency range (10-2 Hz-4 MHz) at room temperature. Overall, a laborious effort with 12 different tests was implemented to fully characterize the developed composites and investigate the correlations between the different qualities. This investigation demonstrated that biochar in the MEX process can be a satisfactory reinforcement agent. Notably, compared to the control samples of pure HDPE, biochar increased the tensile strength by over 20% and flexural strength by 35.9% when added at a loading of 4.0 wt. %. The impact strength and microhardness were also significantly improved. Furthermore, the Direct current (DC) conductivity of insulating HDPE increased by five orders of magnitude at 8.0 wt. % of biochar content, suggesting a percolation threshold. These results highlight the potential of C-based composites for the use in additive manufacturing to further exploit their applicability by providing parts with improved mechanical performance and eco-friendly profiles. The reinforcement of MEX 3D printed parts with eco-friendly biochar. Biochar was obtained from olive trees. Popular high-density polyethylene (HDPE) was the polymeric matrix in the study. biochar increased the tensile strength by over 20% and the flexural strength by 35.9% at a loading of 4 wt. %. The DC conductivity of the insulating HDPE increased by five orders of magnitude at 8 wt. % biochar loading.

Growing concerns over the threat to the geoenvironment from the disposal of municipal solid waste and industrial byproducts created an alarming situation. Hence, their utilization as Anthropogenic (manmade) Resources (read as AnthRes), especially those being generated in millions of tons, such as landfill-mined-soil-likefractions (LFMSF) and red mud (RM), become unavoidable. However, the existing utilization pathways raise questions over their environmental sustainability as they would not control the leaching of microplastics, salts, and heavy metals from these materials. To overcome this situation, the utilization of LFMSF and RM as fillers in manufacturing the polymer composites, which can isolate them from the outside environment, was proposed. In this context, the influence of the most significant parameters like (i) filler content (FC) and (ii) melt-mixing processes on the mechanical, thermal, and morphological characteristics of polypropylene composites were investigated. It was observed that FC and the presence of fiber-like organic matter in LFMSF would significantly influence the mechanical properties of the composites. Subsequently, mathematical models that can be employed for predicting the influence of the above-mentioned parameters on the mechanical properties were developed. Moreover, batch experiments were performed to obtain the leaching characteristics, which revealed that the concentrations of leachable elements from the composites reduced by over 98% as compared to their respective fillers indicative of effective bonding between the polypropylene matrix and filler particles. Hence, the present study established that the LFMSF and RM can be utilized as AnthRes in polymer composites for sustainable development without harming the geoenvironment.