The poor performance and high cost of the starch-sisal fibre composites with open-cell structures prevent their usage as biodegradable biomass to replace plastics. Therefore, inorganic fillers talcum ...powder (TP), CaCO3 (CC) and a bio-filler eggshell powder (EP) were added, and the resulting mechanical properties, water resistance, thermal stability and biodegradation characteristics were compared. Results show that the tensile strength of the EP-composite increases by 34% and the compressive strength of the CC-composite increases by 69% when compared with those of the non-filler (NF) composite. The mechanical properties of the composites improved because of the reduction of starch crystallinity and the formation of new hydrogen bonds. The EP-composite offered optimal cushioning owing to its uniform and dense open-cell structures. Besides, the CC- and EP-composites offered better thermal stability. The composites with fillers were more waterproof than the NF-composite (by approximately 33%). After conducting biodegradability tests for 30 days, the EP-composite lost 67% of its mass, which was more than those associated with the TP- and CC-composites and can be attributed to the presence of organic matter in the EP-composite. These results demonstrate the potential of EP to replace CC and TP for reinforcing the starch-fibre composites with open-cell structures.
Display omitted
•A filler-reinforced rapidly degradable starch-fibre composite with open-cell structures was prepared.•Both bio-fillers and inorganic fillers can improve the mechanical properties, thermal stability and water resistance.•Bio-fillers were advantageous for rapid biodegradation.•Bio-fillers (eggshell powder) have the potential to replace inorganic fillers (talcum powder and CaCO3).
Excessive biofluid around wounds can cause infection and prevent healing. In this study, an anisotropic quaternized chitosan (QC)/sodium alginate (AL)-based aerogel wound dressing was prepared via a ...directional freeze-drying technique inspired by the channel structure used for water transport in trees. The aligned channels provided the dressing with self-pumping ability, allowing it to rapidly and completely remove biofluids and absorb biofluids up to 1292.5 % of its own weight. To enhance the strength of the dressing, a double cross-linked network was constructed based on the QC-AL electrostatic attraction and AL-Ca2+ chelation interaction. The axial compressive strength of the double cross-linked dressing reached 207.3 kPa (ε = 50 %). In addition, the dressing exhibited strong conductive properties (conductivity = 13.0 S/m), antioxidant activities reactive oxygen species (ROS) scavenging ability = 88.0 %, and hemostatic characteristics (blood coagulation index = 1.8 %). The dressing also exhibited powerful antibacterial performance, exhibiting over 98.0 % inhibition of E. coli and S. aureus. Experiments on diabetic mouse models revealed that the dressing considerably promoted wound healing. On day 3, the wound healing rate was 96.7 % faster in the QAC group than in the gauze group. Therefore, the developed dressing may have great potential for chronic wound care.
To solve the problem of environmental pollution caused by plastic food packaging films, a biodegradable chitosan-based film containing micro ramie fibre and lignin was prepared by the casting method. ...With the addition of different ratios of ramie fibre and lignin to the chitosan matrix, a significant improvement in mechanical, water resistance, thermal, and antioxidant properties was observed. The addition of 20 wt% ramie fibre increased the tensile strength by 29.6%. Moreover, the addition of 20 wt% of lignin increased the antioxidant activity by 288%, and reduced the water absorption by 41.2%. However, due to their high pyrolysis temperatures, there was little difference between ramie fibre and lignin in improving the thermal stability. Finally, this study compared the food preservation effects of composite films and PE films. The application evaluation results showed that the composite films were more effective. Overall, the chitosan-based films showed great potential for food packaging.
Display omitted
•Eco-friendly chitosan-based composite film was prepared by casting method.•Ramie fibre was used for the first time to reinforce chitosan-based film.•Ramie fibre reinforced the tensile strength and thermal stability of film.•Lignin enhanced the water resistance, antioxidation and thermal stability of film.•The chitosan-based composite film had great potential for meat packaging.
In the field of medical research, the development of safe and effective wound dressings is a continuous goal. Chitosan (CS) is highly sought after because of its unique biocompatibility, ...biodegradability, antibacterial, and healing-promoting properties. The CS molecule has a significant number of active amino and hydroxyl groups; thus, making substitutions and creating derivatives with varied biochemical properties are relatively straightforward processes. This review addresses the range of functions performed by CS and its derivatives in wound care, such as haemostasis, antibacterial, antioxidant, and wound healing. Furthermore, it summarises the various types of CS-based dressings, their performance features and applications. Finally, the future directions of CS-based dressings are proposed.
Display omitted
Starch is regarded as one of the most promising sustainable materials due to its abundant yield and excellent biodegradability. From the perspective of practical engineering applications, this paper ...systematically describes the development of starch-based bio-composites in the past decade. Packaging properties, processing characteristics, and current challenges for the efficient processing of starch-based bio-composites are reviewed in industrial packaging. Green coatings, binders, adsorbents, flocculants, flame retardants, and emulsifiers are used as examples to illustrate the versatility of starch-based bio-composites in chemical agent applications. In addition, the work compares the application of starch-based bio-composites in conventional spinning with emerging spinning technologies and describes the challenges of electrostatic spinning for preparing nanoscale starch-based fibers. In terms of flexible electronics, the starch-based bio-composites are regard as a solid polymer electrolyte and easily modified porous material. Moreover, we describe the applications of the starch-based gels in tissue engineering, controlled drug release, and medical dressings. Finally, the theoretical input and technical guidance in the advanced sustainable engineering application of the starch-based bio-composites are provided in the work.
Display omitted
Enteromorpha prolifera belonging to the chlorophyta phylum is the main pollutant of “green tide”, and propagates rapidly in recent years. However, there is almost no high-value enteromorpha treatment ...method at present. This study aimed to extract cellulose nanocrystals (CNC) from enteromorpha and prepare the CNC reinforced films based on alginate, carrageenan and shellac for food packaging. The effects of alginate, κ-carrageenan, cellulose nanocrystals and glycerin on the CNC reinforced alginate/carrageenan films (AC films) properties were studied systematically in this work. The results showed that the mechanical properties, swelling properties, and barrier properties of the AC could be adjusted by the concentrations of the different components. In addition, response surface methodology (RSM) was used to optimize the formula of the AC used for food packaging according to the requirements of the practical application. Furthermore, in order to further improve the food packaging capacity of the composite films, shellac was added to the optimized alginate/carrageenan films (OAC films) to obtain the shellac optimized alginate/carrageenan films (SOAC films). Finally, the OAC films and SOAC films showed excellent properties to extend the storage time of chicken breast and cherry tomatoes in the food storage experiment.
•Enteromorpha pollutes the environment and is the main pollutant of “green tide”.•Sodium alginate and κ-carrageenan can be used to prepare the composite films.•Cellulose nanocrystals obtained from enteromorpha could reinforce the composite films.•The composite films with shellac have great potential for food packaging.
Antibacterial hemostatic medical dressings have become feasible solutions in response to the challenging wound-healing process. In this study, a novel fiber-type medical dressing with excellent ...breathable, antibacterial, and hemostatic qualities was created using sodium alginate (SA), microcrystalline cellulose (MCC), polyvinyl alcohol (PVA), and Euphorbia humifusa Willd (EHW) based on microfluidic spinning technology, and the properties of the dressing were characterized. The orthogonal test demonstrates that PVA and MCC can enhance the mechanical properties of the fiber, which is a crucial requirement for fiber assembly to form the dressing. Moreover, the presence of EHW enhances the dressing's antibacterial and hemostatic qualities. The dressings have been proven to have potent antibacterial and hemostatic properties as well as the ability to considerably speed up wound healing and skin tissue regeneration in the in-vitro and in-vivo tests. In conclusion, this innovative fiber-type medical dressing containing SA, MCC, PVA, and EHW has enormous potential for managing wounds caused by bacteria.
Wheat straw is a potentially natural material for production of bio-composites due to its chemical composition. Lignin, cellulose and hemicellulose are closely connected in wheat straw and difficult ...to separate for nano-lignocellulose in high valuable application. The work presented a clean and simple way to prepare biodegradable nano-lignocellulosic membrane with high mechanical strength and water barrier property using nano-lignocellulose derived from wheat straw. Wheat straw was soaked in aqueous solution of urea at 90 °C for 24 h and fibrillated with boiling to obtain urea treated nano-lignocellulose (UNLC). Moreover, starch soluble (SS) latex was mixed with the UNLC slurry for binding the reinforcement for preparing the novel membrane (UNLC/SS). High speed centrifugation realized stratification of the chemical composition from wheat straw. Waxy and lignin as hydrophobic component was located at the surface of the developed membrane, which improved the water barrier property of the membrane. Water contact angle of the lignocellulosic membrane was beyond 110°. The hydrogen bond formation between the starch and cellulose increased the mechanical property of the novel biodegradable membrane. The tensile strength of the nano-lignocellulosic membrane increased from 7.6 MPa to 27.4 MPa. As the high strength, hydrophobic, transparent, biodegradable performance, the bio-composite membrane has many potential industrial applications.
•A biodegradable membrane with high strength, and hydrophobic property was developed.•Layered structure occurred after high-speed centrifugation for hydrophobic surface.•Water contact angles of the novel composite membrane reached 110°.•The tensile strength of the composite membrane increased from 7.6 MPa to 27.4 MPa.
Biomass-based adhesives are gaining attention as environmentally friendly alternatives to toxic petroleum-based adhesives. However, biomass-based adhesives exhibit poor adhesive properties and are ...highly susceptible to failure in humid environments. In this study, a zein-based adhesive with high adhesive strength and good water resistance was prepared by optimizing the solvent composition and adding tannic acid. Adding 10 wt% acetic acid to an aqueous ethanol solvent increased the shear strength by 45.4 % to 3.09 MPa. Moreover, the addition of 6 wt% tannic acid improved the shear strength of the zein-based adhesive in humid environments from 0.63 to 1.58 MPa. The tannic acid-reinforced zein-based adhesive exhibited good adhesive strength in both humid and dry environments, which was maintained for 30 days on glass, and could be applied to a wide range of substrates. Moreover, the adhesive showed an antioxidant activity >94 %, excellent thermal stability, biocompatibility, and antibacterial effect. Therefore, this adhesive has great application prospects in medical, packaging, and other fields.Biomass-based adhesives are gaining attention as environmentally friendly alternatives to toxic petroleum-based adhesives. However, biomass-based adhesives exhibit poor adhesive properties and are highly susceptible to failure in humid environments. In this study, a zein-based adhesive with high adhesive strength and good water resistance was prepared by optimizing the solvent composition and adding tannic acid. Adding 10 wt% acetic acid to an aqueous ethanol solvent increased the shear strength by 45.4 % to 3.09 MPa. Moreover, the addition of 6 wt% tannic acid improved the shear strength of the zein-based adhesive in humid environments from 0.63 to 1.58 MPa. The tannic acid-reinforced zein-based adhesive exhibited good adhesive strength in both humid and dry environments, which was maintained for 30 days on glass, and could be applied to a wide range of substrates. Moreover, the adhesive showed an antioxidant activity >94 %, excellent thermal stability, biocompatibility, and antibacterial effect. Therefore, this adhesive has great application prospects in medical, packaging, and other fields.
Quaternized chitosan (QCS)-based films are garnering considerable attention owing to their multifunctional properties; however, their inherent hydrophilicity limits their application. In this study, ...a fluorine-free superhydrophobic surface for QCS-based film was fabricated using an easy and effective method. The film with hierarchical micro/nano structures (MN-surface) was fabricated by combining the template and spray methods. After modification with polydimethylsiloxane, the MN-surface showed excellent superhydrophobicity, with a water contact angle of 165.7° and a sliding angle of 4.2°. The air cushions captured by the hierarchical micro/nano structures reduced the contact area between water droplets and the MN-surface, giving it excellent self-cleaning ability. Additionally, the microstructures acted as a protective layer for the nanostructures, protecting them against damage during mechanical wear. Thus, the MN-surface exhibited remarkable mechanical robustness against sandpaper abrasion, tape peel-off, bending, stretching, and water flow impact. More importantly, it showed an excellent anti-adhesion effect on bacteria, thereby further lowering the risk of bacterial invasion. Consequently, the superhydrophobic QCS-based film opens up new possibilities for its application in diverse fields.
Display omitted
•The robust superhydrophobic quaternized chitosan-based film was prepared.•The surface exhibits outstanding adhesion properties and self-cleaning ability.•The formed hierarchical micro/nano structures can enhance its mechanical stability.•The surface shows good resistance to high-speed jets and continuous water flow.•The surface has significantly reduced bacterial adhesion by 95.2 %.
PDF
