Poly(lactic acid)-Based Electrospun Fibrous Structures for Biomedical Applications

Poly(lactic acid)(PLA) is an aliphatic polyester that can be derived from natural and renewable resources. Owing to favorable features, such as biocompatibility, biodegradability, good thermal and mechanical performance, and processability, PLA has been considered as one of the most promising biopolymers for biomedical applications. Particularly, electrospun PLA nanofibers with distinguishing characteristics, such as similarity to the extracellular matrix, large specific surface area and high porosity with small pore size and tunable mechanical properties for diverse applications, have recently given rise to advanced spillovers in the medical area. A variety of PLA-based nanofibrous structures have been explored for biomedical purposes, such as wound dressing, drug delivery systems, and tissue engineering scaffolds. This review highlights the recent advances in electrospinning of PLA-based structures for biomedical applications. It also gives a comprehensive discussion about the promising approaches suggested for optimizing the electrospun PLA nanofibrous structures towards the design of specific medical devices with appropriate physical, mechanical and biological functions

Application of Cellulose-Based Materials as Water Purification Filters; A State-of-the-Art Review

Water scarcity, identified as the most serious global risk by the World Economic Forum, poses significant challenges due to its potential impact over the next decade. This study focuses on addressing the pressing issues of water scarcity and water quality through the use of cellulose-based materials for manufacturing water filters. Industrial wastewater containing dyes and heavy metal ions is a major contributor to water pollution, affecting underground water sources. Copper, mercury, chromium, lead, and tin are among the most common and environmentally damaging heavy metal ions due to their high toxicity, low biodegradability, and persistence in the food chain. Water purification processes are crucial for ensuring safe consumption. Bio-compatible and renewable materials have gained attention for water treatment applications in recent years. Cellulose-based materials, such as cellulose nanofibers (CNFs) and cellulose nanocrystals (CNCs), possess unique characteristics including biodegradability, suitable aspect ratio, thermal stability, high strength, stiffness, renewability, and accessibility. This research aims to review the utilization of cellulose-based materials, particularly modified CNC and CNF aerogels, for manufacturing water filters. These materials exhibit high porosity, large specific surface area, and functional groups on their surfaces, making them promising adsorbents for removing water pollutants such as heavy metals, organic dyes, pharmaceutical waste, and oils. Our study demonstrates that modified CNFs and CNCs have shown an exceptional absorption capacity of approximately 98% for heavy metals. By focusing on the specific application of cellulose-based materials for water filtration, this research contributes to the development of effective and sustainable solutions for water purification, addressing the critical challenges posed by water scarcity and pollution

Manufacturing of Fluff Pulp Using Different Pulp Sources and Bentonite on an Industrial Scale for Absorbent Hygienic Products

In this study, for the first time, a composite fluff pulp was produced based on the combination of softwood (i.e., long-length fiber), hardwood (i.e., short-length fiber), non-wooden pulps (i.e., bagasse) and bentonite, with specific amounts to be used in hygienic pads (e.g., baby diapers and sanitary napkins). After the defibration process, the manufactured fluff pulp was placed as an absorbent mass in diapers and sanitary napkins. Therefore, tests related to the fluff pulp, such as grammage, thickness, density, ash content, humidity percentage, pH and brightness, tests related to the manufactured baby diapers, such as absorption capacity, retention rate, retention capacity, absorption time and rewet, and tests related to the sanitary napkin, such as absorption capacity and rewet, were performed according to the related standards. The results demonstrated that increasing the amount of bagasse pulp led to increasing the ash content, pH and density of fluff pulp and decreasing the brightness. The addition of bentonite as a filler also increased ash content and pH of fluff pulp. The results also demonstrated that increasing of bagasse pulp up to 30% in combination with softwood pulp led to increasing absorption capacity, retention rate, retention capacity, absorption time and rewet of baby diapers and of sanitary napkins

Development and Characterization of Sodium Alginate-Based Bio-hybrid Super Absorbent Polymer with High Retention Capacity Suitable for Baby Diapers

Due to their capacity of water absorption, super absorbent polymers (SAPs) are greatly requested in hygienic applications, thus representing large volume products needing for a good biodegradability. This study aims to develop new SAPs for baby diapers by combining sodium alginate (SA) and cellulose nanocrystals (CNC) with acrylic acid (AA). The effect of different AA/SA ratios and CNC concentrations in the presence of ammonium persulfate (APS) as an initiator, and N–N-methylene bis-acrylamide (NMBA) as a cross-linker is investigated. We assess morphological and physicochemical properties of the SAPs, as well as their absorption characteristics and rheological properties. The results show that SAPs with AA/SA weight ratio of 70:30 containing 2% w/w CNC have the highest water absorption capacity, i.e., 78.4 g/g in saline solution. These SAPs also demonstrate high retention capacity and better absorption capacity under load than other SAPs. We further optimize the formulation by increasing the neutralization degree of AA and reducing the solid content, reaching an absorption capacity in the salt solution up to 100.08 g/g. Finally, the absorbent core made with fewer amounts of SAPs and fluff pulp led to functional properties superior to those of commercial baby diapers. High polysaccharide content SAPs could contribute to improve diaper sustainability