Volume 20 Issue 2

On September 3^rd, 2024, North Carolina State University, the University of British Columbia, Aalto University, the University of Chile, and the University of the Basque Country organized a global webinar on allocation methods for recycled fibers. The event focused on the challenges and complexities associated with allocation methods for open-loop recycling systems, focusing on bio-based fibers for packaging. The webinar featured three expert presentations by Dr. Tomas Ekvall, Dr. Caroline Gaudreault, and MSc. Ivana Azuaje, each offering valuable insights into the topic.

The term “nanocellulose” encompasses a wide range of cellulose-derived nanomaterials, which are characterized by their diverse morphologies and chemical structures at the nanometer scale. In recent years, there has been a remarkable increase in the use of nanocellulose in regenerative medicine. Of particular interest is the in vitro culture of pluripotent stem cells, which has led to a growing demand for animal-free media and scaffolds in stem cell culture. Extracellular matrix (ECM) plays a pivotal role in regulating the proliferation and differentiation of stem cells, with fibrous collagen and glycosaminoglycans serving as structural and functional supports. In this context, nanocellulose has garnered significant interest as potential ECM mimetics, due to its rigid fiber form and its regular interfacial structures. The use of natural polysaccharide nanofibers would represent a promising avenue for the functional design of animal-free cell culture scaffolds, with the potential to significantly advance the regulation of stem cell culture in regenerative medicine.

Photovoltaic (PV) systems play an important role in reducing society’s dependence on carbon-based energy sources, and their coupling with timber buildings is an interesting and expected solution for meeting sustainability requirements in the modern built environment. However, both PV systems and timber structures have unique fire safety challenges, and their combination may introduce additional risks. Therefore, relevant fire hazards associated with each of the technologies and their pairing are discussed. The findings highlight the importance of revising fire testing standards and developing tailored safety measures to identify and manage these risks.

In the lignocellulosic biorefinery concept, by-products from sawmills have been redefined and considered as raw materials to produce high-value products. Wood extractives are not an exception despite being found in smaller proportions. The extractive-based components can offer competitive advantages over traditional market products and promote a circular economy. Tannins demonstrate applicability in adhesives, fertilizers, antioxidant food packaging, and water treatment. However, there are still challenges on an industrial scale.

Bio-based wood adhesives are increasingly receiving greater attention than those of synthetic formaldehyde-based adhesives from petroleum sources in response to climate change. In this respect, this editorial provides an overview on the transition of formaldehyde-based adhesives to bio-based adhesives for the bonding of wood. This transition is underway in academia and industry for practical applications. Bio-based adhesives offer low toxicity, lower greenhouse gas emissions, and increased sustainability with circular economy by promoting renewable and degradable sources, which generates a driving force for the transition.

Phytochemicals are non-nutritive plant components having bioactive activities. Compared with synthetic chemicals, phytochemicals have numerous advantages, and they are now widely used in health foods, cosmetics, and pharmaceuticals. Phytochemicals also provide a rich natural resource pool for new health food and medicine development. Because of their wide uses, phytochemicals have high economic value for their development and utilization. Phytochemicals are present in a vast number of plants, and their production has a wide range of feedstock sources. In traditional biomass processing, phytochemicals are often considered as wastes and are not recovered. In order to improve the economic benefits, the extraction of phytochemicals has now become an attractive sub-process during the biomass processing. However, the low content of phytochemicals in plants makes their extraction challenging. Efforts are needed to increase the phytochemical content in plants and develop more efficient extraction and separation processes. This editorial briefly discusses phytochemicals and their extraction to improve the economic benefits of biomass processing.

Corrugated board is a ubiquitous material, playing a critical role in modern packaging, transportation, and storage industries. While traditional flute shapes like sinusoidal waves dominate production, exploring and implementing novel fluting geometries could significantly enhance the mechanical properties of this material. This editorial discusses the theoretical future of various flute shapes and their potential to improve mechanical performances, such as bending stiffness and load-bearing capacity. Embracing innovative design and production techniques could lead to more sustainable and high-performing usages for corrugated cardboard for diverse applications.

Suzhou oil-paper umbrellas, as a significant part of China’s intangible cultural heritage, exemplify the harmonious integration of nature and art through their intricate craftsmanship. These umbrellas are not only functional objects but also cultural symbols, reflecting centuries of traditional skills in bamboo frame making and oil-paper production. However, the preservation of these techniques faces critical challenges, including an aging artisan population, a lack of successors, and insufficient integration of local industries with cultural heritage protection efforts. The current approaches to safeguarding these crafts often focus on superficial aspects, neglecting the core techniques of bamboo processing and paper-making. This editorial considers the cultural value of Suzhou oil-paper umbrella craftsmanship, identifies the challenges in its preservation, and explores revitalization strategies through educational tourism. The research employs a comprehensive analysis of the cultural significance, current preservation efforts, and potential for sustainable development. The main contribution of this study lies in highlighting the potential of educational tourism as a vehicle for cultural heritage conservation and local economic development, providing a framework for the sustainable revitalization of this unique traditional craft.

Tannin-based biomass foam was prepared through a self-foaming process at room temperature. The material’s density, porosity, microstructure, mechanical properties, thermal stability, limiting oxygen index (LOI), brittleness, as well as water absorption and retention properties, were studied. Adding 2% bamboo fibers in varying forms did not affect the uniformity of the foam cells. The density, porosity, thermal stability, and LOI of the foam material remained largely unchanged. The compressive strength of the unmodified tannin foam was 0.043 MPa, while the addition of 2% bamboo fibers increased the compressive strength by 72%. Even when the effect of density was excluded, the specific compressive strength was enhanced by 60%. Additionally, brittleness, measured as the slagging percentage, was significantly reduced from 16.12% to 4.78%. The modified foam could absorb up to 26.5% of its weight in water, with excellent water retention capabilities of 78.1% after 120 h while retaining its structural integrity under intermittent wetting conditions, making it suitable for vertical greening applications. This demonstrates its suitability for vertical greening applications, where moisture exposure is frequent. In conclusion, the bamboo fiber-reinforced tannin-based foam exhibits excellent mechanical properties and superior water absorption and retention performance.

Molded pulp products (MPP) products can accommodate a variety of fiber types and additives, including agricultural residues. This work showed the industrial scale production of molded pulp food trays made of double lined kraft clipping fibers with the addition of pistachio shell (PS) powder at levels from 5 to 30 wt% and evaluated the mechanical and barrier properties of the trays. The PS powder used to make the trays was ground using an impact mill and a cryo mill to a D50 of approximately 50 microns. Tray compression strength was tested to simulate the wrapping of food trays with plastic wrap. Additionally, the tray material’s basis weight, thickness, density, tensile strength, short span compressive strength, and absorptiveness were determined. The results showed that compared to the control tray sample, the trays containing the cryo-milled pistachio powder had essentially the same engineering properties as the control trays without PS. For the trays made with the impact-milled powder, the tensile strength, bending resistance, and compressive strength increased relative to the control 11.3%, 6.2%, and 13.5%, respectively. The study demonstrates a method to evaluate the incorporation of alternative materials into pulp molded products.