Search Results (45)

This study focused on investigating the flammability and thermal degradation behavior of wood fiber-reinforced composites consisting of xanthan gum (XG) and gelatin (GEL). These materials could potentially be used as novel bio-based and biodegradable topsoil covers (TSCs) to support reforestation practices. To improve the thermal properties of these composites, xanthan gum was cross-linked with citric acid (CA) or tannic acid (TA) and eventually coated with casein, while gelatin was cross-linked with tannic acid. Thermogravimetric analysis (TGA) showed that thermal degradation of all the prepared samples started at temperatures of 200 °C for xanthan-based samples and 300 °C for gelatin-based samples, which is well above the typical operating conditions for TSCs in their intended application. Single-flame-source tests demonstrated that the CA cross-linked xanthan-based TSCs coated with casein and all the gelatin-based TSCs had excellent self-extinguishing properties. Additionally, Limiting Oxygen Index (LOI) tests showed that gelatin-based composites had LOI values between 30 and 40 vol% O₂, increasing with a higher gelatin-to-wood fiber ratio. These results demonstrated the potential of cross-linked biopolymers (e.g., xanthan and gelatin) as green flame retardants for the production of wood fiber-filled TSCs for use in forestry. Full article

The environmental impact of petroleum-based plastics has driven a global shift toward sustainable alternatives like biodegradable polymers, including polylactic acid (PLA), polybutylene succinate (PBS), and polycaprolactone (PCL). Yet, these bioplastics often face limitations in mechanical and thermal properties, hindering broader use. Reinforcement with cellulose nanofibrils (CNFs) has shown promise, yet most research focuses on conventional sources like wood pulp and cotton, neglecting agricultural residues. This review addresses the potential of maize husk, a lignocellulosic waste abundant in South Africa, as a source of CNFs. It evaluates the literature on the structure, extraction, characterisation, and integration of maize husk-derived CNFs into biodegradable polymers. The review examines the chemical composition, extraction methods, and key physicochemical properties that affect performance when blended with PLA, PBS, or PCL. However, high lignin content and heterogeneity pose extraction and dispersion challenges. Optimised maize husk CNFs can enhance the mechanical strength, barrier properties, and thermal resistance of biopolymer systems. This review highlights potential applications in packaging, biomedical, and agricultural sectors, aligning with South African bioeconomic goals. It concludes by identifying research priorities for improving compatibility and processing at an industrial scale, paving the way for maize husk CNFs as effective, locally sourced reinforcements in green material innovation. Full article

Horticultural substrates based on coconut fibre are among the most commonly used growing media, but with limited durability. This study presents methods for modifying coconut fibre through surface coating with biopolymers, where polymerisation was initiated in the applied solution. Additionally, the suitability of adding pelletised biochar was analysed. A biomonomer derived from wood processing was used both for fibre surface modification and for binding biochar into pellets. Surface modification through biopolymer coating resulted in changes to selected physicochemical properties. It was found that the coating significantly altered the porosity of the substrate. Depending on the type of coconut fibre, the differences in porosity compared to the unmodified substrate ranged from 12 to 24%. This directly influenced bulk density, which is a crucial parameter in the preparation of substrates for plant growth. The surface properties of the modified substrates also affected sorption and retention capacities. From the perspective of plant production, the supply of bioavailable forms of potassium and phosphorus is essential. Coating and the addition of pelletised biochar, regardless of the type of fibre used, significantly increased the release of PO₄³⁻ and K⁺ compared to unmodified substrates. The physiological parameters in plants confirmed the suitability of the modified substrates for plant production. Full article

A typical Mashrabiya in Islamic architecture represents an integral climatic and sustainable solution, not only by offering recycling and the responsible use of small pieces of wood assembled in stunning geometrical and natural abstract lattice panels, but also because it offers air cooling, filtration, and flow from the exterior to the interior of a building. This leads to the air flow being cooled by the water spray offered by the interior patio fountains, in addition to protecting the sanctity and privacy of a building’s inhabitants, which complies with religious beliefs and social considerations. This integral sustainable solution acts on multiple scales: material recycling and responsible use, as well as climatic and socio-cultural considerations similar to Gaudi’s approach with Trencadís technology, not far from the Arabic and Islamic architectural influence revived in the Catalan Modernism contemporary to his time. In these footsteps, we explore the Mashrabiya of our time: an interactive and living architectural membrane, a soft interface that reacts by growing, giving shade, filtrating air, and transforming in time. Despite attempts to design a contemporary concept of the Mashrabiya, none of them have adopted the living organism to form an interactive living lattice architectural system. In this work, we propose the biodigital micro-cellular Mashrabiya as a novel idea and a proof of concept based on employing the authors’ previously published research findings to utilize eco-friendly biopolymers inoculated with useful native–domestic microbial strains to act as soft and living membranes, where these organisms grow and vary in their chemical and physical characteristics, sustainable function, and industrial value. This study implements an analytical–descriptive methodology to analyze the key characteristics of a traditional Mashrabiya as an integral sustainable solution and how the proposed micro-cellular biodigital Mashrabiya system can fulfill these criteria to be integrated into the built environment, forging future research trajectories on the bio-/micro-environmental compatibility of this biomaterial-based biodigital Mashrabiya system by understanding these materials’ physical, chemical, and physiological traits and their sustainable value. In this work, a biodigital Mashrabiya is proposed based on employing previous research findings on experimentally analyzed biomaterials from a biomineralized calcium-phosphate-based hydrogel and bio-welded seashell–mycelium biocomposite in forging the lattice system of a biodigital Mashrabiya, analyzing the feasibility and sustainability impact of these systems for integration into the architectural built environment. Full article

The enhanced use of wood residues from the timber industry contributes to mitigating the global climate crisis. Currently, bark, a by-product of the timber industry, is primarily burned for thermal energy generation. However, with the growing demand for lignocellulosic products and the emphasis on extending life cycles, it would be more beneficial to prioritize substantial uses of bark over thermal utilization. Although numerous methods for substantial bark utilization have been explored, a significant untapped potential remains. The extractives obtained through water extraction, for instance, can be applied to various further uses like biopolymers or medical applications. This study investigates the impact of hot water extraction on the mechanical and physical properties of bark-based panels, with the aim of extending the life cycle of tree bark and its valorization in bio-based composites. The findings demonstrate that hot water extraction can enhance the bending properties (modulus of rupture, modulus of elasticity) of bark-based panels. Additionally, the extractives obtained from the process have potential applications in the pharmaceutical and adhesive industries. The study also includes an LCIA that highlights the differences between the three scenarios addressed in this research, namely energy generation from bark-based biomass, extraction of bark, and use of extracted bark residues in the production of bark-based particleboard. Full article

Bioresources have been gaining popularity due to their abundance, renewability, and recyclability. Nevertheless, given their diverse composition and complex hierarchical structures, these bio-based sources must be carefully processed to effectively extract valuable raw polymeric materials suitable for producing man-made organic fibres. This review will first highlight the most relevant bio-based sources, with a particular focus on promising unconventional biomass sources (terrestrial vegetables, aquatic vegetables, fungi, and insects), as well as agroforestry and industrial biowaste (food, paper/wood, and textile). For each source, typical applications and the biopolymers usually extracted will also be outlined. Furthermore, acknowledging the challenging lignocellulosic structure and composition of these sources, an overview of conventional and emerging pre-treatments and extraction methods, namely physical, chemical, physicochemical, and biological methodologies, will also be presented. Additionally, this review aims to explore the applications of the compounds obtained in the production of man-made organic fibres (MMOFs). A brief description of their evolution and their distinct properties will be described, as well as the most prominent commercial MMOFs currently available. Ultimately, this review concludes with future perspectives concerning the pursuit of greener and sustainable polymeric sources, as well as effective extraction processes. The potential and main challenges of implementing these sources in the production of alternative man-made organic fibres for diverse applications will also be highlighted. Full article

Understanding the deterioration processes in wooden artefacts is essential for accurately assessing their conservation status and developing effective preservation strategies. Advanced imaging techniques are currently being explored to study the impact of chemical changes on the structural and mechanical properties of wood. Nonlinear optical modalities, including second harmonic generation (SHG) and two-photon excited fluorescence (TPEF), combined with fluorescence lifetime imaging microscopy (FLIM), offer a promising non-destructive diagnostic method for evaluating lignocellulose-based materials. In this study, we employed a nonlinear multimodal approach to examine the effects of artificially induced delignification on samples of Norway spruce (Picea abies) and European beech (Fagus sylvatica) subjected to increasing treatment durations. The integration of SHG/TPEF imaging and multi-component fluorescence lifetime analysis enabled the detection of localized variations in nonlinear signals and τ-phase of key biopolymers within wood cell walls. This methodology provides a powerful tool for early detection of wood deterioration, facilitating proactive conservation efforts of wooden artefacts. Full article

Lignin is one of the three major components of the cell wall of lignocellulosic biomaterials. It is the second-most abundant polymer in nature. It is a complex and heterogeneous polymer found in the cell walls of lignocellulosic biomass. Lignin’s predominant composition, which is rich in carbon and aromatic structures, enhances its value by enabling the development of high-value chemicals and bio-based materials. As one of the most affluent natural renewable sources of aromatic structures and the world’s second-largest renewable source of carbon, lignin possesses a thermal value comparable to that of carbon. Its aromatic constituents exhibit unique chemical properties and significant bioactive effects, making lignin a crucial material in various advanced applications. Different chemical fractionation methods have been designed to overcome the obstacles to extracting the lignin biopolymer from lignocellulosic biomass. Lignin fractionation is a process that involves separating lignin from other components of biomass feedstock, such as cellulose and hemicellulose. This process is commonly used in the paper and pulp industry to obtain valuable lignin derivatives that can be used in various applications, including, among others, biofuels, chemicals, and biomaterials. In the brief overview described in this proceedings paper, we provide a comprehensive chemical overview of the current processes for extracting technical lignin from wood and lignocellulosic biomass, critically evaluating the advantages and limitations of each method. Full article

In recent years, the environmental impacts of plastic production and consumption have become increasingly significant, particularly due to their petroleum-based origins and the substantial waste management challenges they pose. Currently, global plastic waste production has reached 413.8 million metric tons across 192 countries, contributing notably to greenhouse gas emissions. Bioplastics have emerged as eco-friendly alternatives, with bioplastic carrier bags composed of 20% starch, 10% additives, and 70% polybutylene adipate terephthalate (PBAT) being the focus of this research. This study aimed to evaluate the biodegradation of these bioplastic bags under industrial composting conditions, addressing the gap in the existing literature that often lacks real-world applicability. A large-scale composting experiment was conducted using 37.5 tons of manure/wood and 50 tons of biopolymer bags over 12 weeks. Results showed that compost temperatures peaked at 70 °C and remained above 50 °C, pH levels stabilized at 8.16, and electrical conductivity was recorded at 1251 μs cm⁻¹. Significant changes were observed in key metrics, such as the carbon-to-nitrogen ratio and organic matter content. Disintegration tests revealed that 95% of the bags disintegrated by the 12th week, though ecotoxicity tests indicated varying germination inhibition rates. Advanced analytical methods (Fourier transform infrared spectroscopy, gas chromatography coupled with mass spectrometry) highlighted morphological and chemical transformations in the bags. This research enhances understanding of bioplastic degradation in real-world composting environments and suggests potential improvements to existing standards, promoting sustainable waste management solutions. Full article

Polymer blends containing up to 70% organosolv lignin content and lyotropic cellulose derivatives have been established as “lignin inks” for direct ink writing of fully biobased 3D parts. However, a fast-crosslinking mechanism is needed to improve throughput and design space. In this paper, UV-photocrosslinkable organosolv lignin/hydroxypropyl cellulose inks are formulated through doping with common photocrosslinkers. The most potent photocrosslinkers for neat hydroxypropyl cellulose, lignin and their blends are determined through a series of DOEs. Hydroxypropyl cellulose is significantly more amenable to photocrosslinking than organosolv lignin. The optimal photocrosslinkable ink formulations are printable and exhibit up to 70% gel content, although thermal post-curing remains essential. Chemical, thermal, and mechanical investigations of the photocrosslinked 3D parts evidence efficient crosslinking of HPC through its hydroxyl groups, while lignin appears internally plasticized and/or degraded during inefficient photocrosslinking. Despite this, photocrosslinkable inks exhibit improved tensile properties, shape flexibility, and fidelity. The heterogeneous crosslinking and residual creep highlight the need to further activate lignin for homogeneous photocrosslinking in order to fully exploit the potential of lignin inks in DIW. Full article

This study explores the use of pine wood biochar (BC) waste gasified at 950 °C as fillers in polymer matrices to create BC@biopolymer composites with perspectives in groundwater remediation. Four biochar samples underwent different sieving and grinding processes and were extensively characterized via UV–Vis, FTIR, and FESEM–EDS, highlighting the fact that that BCs are essentially graphitic in nature with a sponge-like morphology. The grinding process influences the particle size, reducing the specific surface area by about 30% (evaluated by BET). The adsorption performances of raw BC were validated via an adsorption isotherm using trichloroethylene (TCE) as a model contaminant. A selected BC sample was used to produce hydrophilic, stable polymer composites with chitosan (CS), alginate (ALG), potato starch (PST), and sodium carboxymethylcellulose (CMC) via a simple blending approach. Pilot sedimentation tests over 7 days in water identified BC@PST and BC@CMC as the most stable suspensions due to a combination of both hydrogen bonds and physical entrapment, as studied by FTIR. BC@CMC showed optimal distribution and retention properties without clogging in breakthrough tests. The study concludes that biopolymer-based biochar composites with improved stability in aqueous environments hold significant promise for addressing various groundwater pollution challenges. Full article

(1) The excessive and incorrect use of agricultural pesticides has caused environmental pollution, with a final destination in aquatic environments. Among the widely used agricultural pesticides, glyphosate stands out for weed control, which according to the World Health Organization (WHO) is potentially carcinogenic in humans. Once in an aquatic environment, decontamination aimed at removing the pesticide is not always a simple task. In this sense, it is necessary to develop low-cost, sustainable procedures with a high remediation capacity. (2) In this context, a nanocellulose-based biopolymer was developed to removal glyphosate from aquatic environments. Nanocellulose was obtained from a cellulose sample from eucalyptus wood and was characterized by scanning and double-beam electron microscopy, scanning microscopy with an energy dispersive detector and Fourier transform infrared (FTIR) spectroscopy. Adsorption studies were carried out to evaluate the retention of glyphosate by nanocellulose. (3) Nanocellulose showed a value of 4.7 mg of glyphosate per gram of nanocellulose, and organomodified nanocellulose showed the removal of 6.1 mg of glyphosate per gram of nanocellulose, as evaluated in pseudo-first-order kinetic models. (4) The biomaterial has a sustainable and renewable origin, has potential for contaminant removal and can be applied to contaminated aquatic systems. Full article

In recent years, polyhydroxyalkanoates (PHAs) have gained notoriety because of their desirable properties that include proven biodegradability, biocompatibility, and thermal stability, which make them suitable alternatives to fossil-based polymers. However, the widespread use of PHAs is still challenging because of their production costs, which are greatly associated with the cultivation medium used for bacterial cultivation. In Portugal, one-quarter of the forest area is covered by Eucalyptus globulus wood, making its residues a cheap, abundant, and sustainable potential carbon source for biotechnological uses. In this work, eucalyptus bark was used as the sole feedstock for PHA production in a circular bioeconomic approach. Eucalyptus bark hydrolysate was obtained after enzymatic saccharification using Cellic^® CTec3, resulting in a sugar-rich solution containing glucose and xylose. Although with differing performances, several bacteria were able to grow and produce PHA with distinct compositions, using the enzymatic hydrolysate as the sole carbon source. Pseudomonas citronellolis NRRL B-2504 achieved a high cellular growth rate in bioreactor assays (24.4 ± 0.15 g/L) but presented a low accumulation of a medium-chain-length PHA (mcl-PHA) comprising the monomers hydroxydecanoate (HD, 65%), hydroxydodecanoate (HDd, 25%), and hydroxytetradecanoate (HTd, 14%). Burkholderia thailandensis E264, on the other hand, reached a lower cellular growth rate (8.87 ± 0.34 g/L) but showed a higher biopolymer accumulation, with a polyhydroxybutyrate (PHB) content in the cells of 12.3 wt.%. The new isolate, Pseudomonas sp., revealed that under nitrogen availability, it was able to reach a higher accumulation of the homopolymer PHB (31 wt.%). These results, although preliminary, demonstrate the suitability of eucalyptus bark’s enzymatic hydrolysate as a feedstock for PHA production, thus offering an exciting avenue for achieving sustainable and environmentally responsible plastic products from an undervalued forestry waste. Full article

This review emphasizes the recent ongoing shift in the wood coating industry towards bio-based resources and circular economy principles, promoting eco-friendly alternatives. In addressing wood’s vulnerabilities, this study investigates the use of natural compounds and biopolymers to enhance wood coatings. These materials contribute to protective matrices that safeguard wood surfaces against diverse challenges. Essential oils, vegetable oils, and bio-based polymers are explored for their potential in crafting eco-friendly and durable coating matrices. Furthermore, this review covers efforts to counter weathering and biological decay through the application of various natural compounds and extracts. It evaluates the effectiveness of different bio-based alternatives to traditional chemical preservatives and highlights promising candidates. This review also delves into the incorporation of sustainable pigments and dyes into wood coatings to enhance both protective and aesthetic qualities. Innovative pigments are able to provide visually appealing solutions in line with sustainability principles. As the wood coating industry embraces bio-based resources and the circular economy, researchers are actively developing protective solutions that encompass the coating matrix, preservatives, bio-based fillers, and natural-pigment dyes. This review showcases the continuous efforts of academia and industry to enhance wood coatings’ effectiveness, durability, and sustainability, while maintaining their aesthetic appeal. Full article

In this study, polymer biocomposites based on poly(3-hydroxybutyrate-co-3-hydroxyvalerate) PHBV biopolymers with Arbocel C350 SR wood fiber filler with mass contents of 15%, 30%, and 45% were described. Samples for testing were produced using the injection molding process. The shrinkage of the produced composites was determined, as well as the basic mechanical properties on the basis of the uniaxial static tensile test, hardness, and impact tensile test. The dimensional stability of samples was subject to temperature and humidity in the water absorption test. This research was carried out in terms of the problems with composite processing and use of products. This paper contains many remarks and conclusions regarding the processing and exploitation of the tested products, which can be extended to a larger range of cellulose fillers. It was found that it was possible to produce the tested type of composites with a content of up to 45 wt. of filler. However, the mechanical properties of the tested composites made it possible to use them for the production of selected products. These conclusions allow for conducting future research toward the effective use of WPC composites with a PHBV matrix and fibrous fillers of natural origin. Full article