Synthesis of bio-based poly(diethylene furanoate)-block-polylactide copolymers with UV blocking properties

Incorporating tannin onto regenerated cellulose film towards sustainable active packaging

This work reports the preparation of nano lignin-rich fraction material via green technology from the holistic use of lignocellulosic biomass bamboo. The bamboo is first chemically treated, followed by acid precipitation to extract bamboo-derived macro lignin-rich fraction material. The nano lignin-rich fraction material was then prepared via ultrasonication technique from the extracted bamboo-derived macro lignin-rich fraction material. The confirmation of the distinct lignin functional groups in the extracted lignin-rich fractions has been done by FTIR. Surface morphology by FESEM and TEM revealed spherical nano-lignin-rich fraction materials from extracted bamboo-derived macro lignin-rich fraction materials. DPPH assays indicated that both the obtained fractions depict beneficial antioxidant characteristics. They were found to be effective in terms of their antibacterial activity against both gram-positive bacteria Staphylococcus aureus (S.aureus) and gram-negative bacteria Escherichia coli (E.coli), using the disc diffusion method. These fractions have UV blocking property, and nano-lignin-rich fraction material acts as a more potential UV blocking agent than others. Thus, the nano-lignin-rich fraction material has great potential as a high antioxidant, antibacterial, and UV blocking agent useful in biomedical applications. Highlights Extraction of macro-lignin rich fraction material using chemical treatment of lignocellulosic biomass bamboo via refluxing followed by acid precipitation. Preparation of nano-lignin rich fraction material from extracted bamboo-derived macro-lignin rich fraction material via ultrasonication technique as a green technology. Structural and surface morphology of the extracted macro-lignin & nano lignin-rich fraction materials have been analyzed by XRD, FTIR, EDX, SEM and TEM. The macro lignin & nano lignin-rich fraction materials showed good antioxidant, antibacterial activity and UV-blocking properties, but the nano-lignin rich fraction material exhibited more efficient properties.

Ductile appearance, remarkable length-diameter ratio, flexible fabrication properties and featured additional functions of functional composite fibers elicit great interest in applications. In this paper, chitosan/poly(vinyl alcohol) composite fibers with different graphene oxide additive (1-7 wt.%) were spun via continuous wet-spinning route and the resultant fibers revealed improved thermal, UV blocking and dye absorptive properties. In details, the component of fibers was characterized by SEM, TEM, FTIR, XRD and the results indicated that the graphene oxide dispersed well in chitosan/PVA matrix and the hydrogen bond was occurred between these components. As expected, the highest graphene oxide content case (7 wt.% GO) possessed the extraordinary UV blocking property as its UPF value reached to 500 arising from UPF=8.11 of 0 wt.% GO case. However, the composite fiber with 1 wt.% GO, rather than 7 wt.% GO, expressed the remarkable thermal stability and dye absorptive property, and the dye absorptive property of 1 wt.% GO showed the highest absorptive capacity of 407 mg/g among all the resultant fibers.

In order to fabricate a novel ZnO/cotton composite, a high proportion of ZnO nanoparticles were assembled in cotton fibers, and the as-obtained cotton fabric can possess better UV blocking property compared with common ZnO/cotton composite. Firstly, the cotton fibers were pre-treated by hydrogen peroxide solution(H2O2) and sodium hydroxide(NaOH), urea(CON2H4). Secondly, the fabric was fabricated via in situ deposition. The effects of concentration of treatment liquid, ammonia-smoking time and curing temperature on the tensile property of the fabric, UV blocking property and water-washing durability test of as-obtained cotton fabrics were investigated. Thirdly, the as-obtained cotton sample was characterized by X-ray diffraction(XRD) and field emission scanning electron microscopy(FESEM). It was shown that ZnO nanoparticles were assembled between cotton fibers, the surface and inside of the lumen and the mesopores of cotton fibers, while the content of nano-ZnO assembled in fabric can reach 15.63wt%. It is proved that the finished fabric can obtain a very excellent UV blocking property, under the condition of zinc ion in concentration of 15wt%, ammonia-smoking time for 10 min, curing temperature at 150 °C for 2 min.

Cotton fabrics have been used in a variety of applications due to its attractive properties of softness, comfort, warmth, biodegradability and breathability. Coating cotton fabrics with photocatalytic materials can extend their use as self-cleaning and other practical applications. In this study, coating of cotton fabrics with dye sensitized/TiO2 for self-cleaning and UV blocking properties has been reported. Phthalocyanine based reactive dye, Reactive Blue-25 (RB-25), has been used as a visible light scavenger for TiO2. RB-25/TiO2 hybrid sol was prepared by sol–gel method and coated on the cotton fabrics via dip-pad-dry-cure method. The coated cotton fabric was characterized by FTIR-ATR, UV–Visible absorption, XRD, SEM and reflectance measurements. The surface studies confirmed the stable attachment of RB-25/TiO2 on the cotton fabric while photocatalytic and UV absorption studies shown that the RB-25/TiO2 coated cotton fabric exhibit substantial visible light driven self-cleaning and UV blocking properties. Rhodamine B (RhB) dye was used as to examine the photocatalytic efficiency of the coated cotton fabric. 91% RhB was degraded in 180 min when exposed to visible light in the presence of RB-25/TiO2 coated cotton fabric.

A novel PVP-ALG/ZnO hydrogel nanocomposite film was synthesized using a solution casting method. By incorporating ZnO nanoparticles into a polyvinylpyrrolidone (PVP) and sodium alginate (ALG) hydrogel, the nanocomposite film demonstrated enhanced antimicrobial, mechanical and UV-blocking properties. Characterization techniques, including XRD, SEM, TEM and UTM, revealed an optimal tensile strength at a 0.0075 g ZnO composition. The composite exhibited superior swelling behaviour compared to pure PVP-ALG hydrogel in distilled water and buffer solution of pH 6.8. Drug-loading studies with cephalexin showed slower, sustained release under intestinal pH (6.8), attributed to ZnO-induced interactions. Antimicrobial analysis confirmed enhanced effectiveness and UV-blocking tests highlighted a high sun protection factor (SPF) of 7.9 for the nanocomposite film. The results highlighted the potential of the PVP-ALG/ZnO hydrogel as an excellent option for use in biomedical and pharmaceutical fields, especially for sustained drug delivery and protective applications.

In this study, we evaluated the UV transmittance of spectacle lenses in the Turkish market, which are reported to have UV blocking properties, and tested their suitability. Samples were obtained from patients who were admitted to the ophthalmology outpatient clinic of our hospital for refractive error and who wore glasses as UV block. No limitation was made regarding the spectacle size and duration of spectacle wear. Measurements were tested by the principal investigator using an ultraviolet detector. The right and left lens were measured separately. All measurements were performed at room temperature (22-25°C) in a humidity regulated (20-40%) room without direct light. UV protection level was measured for 120 spectacles used for refractive errors. Only 28 (23.3%) of 120 glasses had protection level up to 400 nm UV. Twenty-four (20%) of the glasses had a protection level of 0 even though they were labeled as having UV blocking properties. It is clear that strict regulations need to be implemented to improve the protection levels of glasses.

Waste cotton clothes, including post-consumer denim fabrics, are abundant biopolymer sources due to their high cellulose content. These waste materials commonly end up in landfills, posing health and environmental concerns and losing valuable cellulosic materials. To address these, this study aims to extract and characterize microcrystalline cellulose (MCC) from post-consumer indigo denim fabrics using a one-step hydrothermal method and evaluate its UV-blocking properties. FTIR and TGA analysis of raw and bleached denim confirmed the presence and purity of cotton cellulose and the indigo dye. Extracted MCC yielded 70-84%, with a degree of polymerization (DP) of 281-299. XRD analysis of the MCC showed a cellulose Type I structure. FTIR suggests the removal of amorphous phases of cellulose, leaving the crystalline structure. SEM meanwhile revealed rod-shaped and rough-surfaced MCC particles with diameters of 10-20 μm and lengths of 45-60 μm. Both FTIR and SEM indicated the retention of indigo dye on MCC surface. Increased acid hydrolysis time led to smaller particle sizes and higher degree of crystallinity (CrI). Indigo PVA-MCC films showed good transparency and effective UV blocking. These results indicate the successful conversion of denim to MCC via the hydrothermal method and the stability of indigo dye in the cellulose matrix.

Improving barrier and antibacterial properties of chitosan composite films by incorporating lignin nanoparticles and acylated soy protein isolate nanogel

Lignin nanorods reinforced nanocomposite hydrogels with UV-shielding, anti-freezing and anti-drying applications

New nanocomposite materials with UV-NIR blocking properties and hues ranging from green to brown were prepared by integrating inorganic tantalum octahedral cluster building blocks prepared via solid-state chemistry in a PMMA matrix. After the synthesis by the solid-state chemical reaction of the K4[{Ta6Bri12}Bra6] ternary halide, built-up from [{Ta6Bri12}Bra6]4- anionic building blocks, and potassium cations, the potassium cations were replaced by functional organic cations (Kat+) bearing a methacrylate function. The resulting intermediate, (Kat)2[{Ta6Bri12}Bra6], was then incorporated homogeneously by copolymerization with MMA into transparent PMMA matrices to form a brown transparent hybrid composite Ta@PMMAbrown. The color of the composites was tuned by controlling the charge and consequently the oxidation state of the cluster building block. Ta@PMMAgreen was obtained through the two-electron reduction of the [{Ta6Bri12}Bra6]2- building blocks from Ta@PMMAbrown in solution. Indeed, the control of the oxidation state of the Ta6 cluster inorganic building blocks occurred inside the copolymer, which not only allowed the tuning of the optical properties of the composite in the visible region but also allowed the tuning of its UV and NIR blocking properties.

Soy protein isolated (SPI) have a wide application in the food packaging, but their water resistance, mechanical properties and antibacterial properties are not ideal for directly use. In our study, we developed a series of SPI composite films loaded with cinnamaldehyde and titanium dioxide (TiO2). X‐ray diffraction (XRD), UV scanning spectra (UV) and spectro colorimeter were applied to indicate the structure of films. The incorporation of TiO2 (0.5%) caused a subsequent effect on the tensile property, UV blocking properties and water vapor properties (WVP). On the other hand, SPI film composed with a constant amount of TiO2 and different concentration of cinnamaldehyde showed an excellent synergistic effect to improve the tensile property, moisture content, UV blocking properties, water vapor properties and morphological characteristics. Furthermore, the composite films exhibited superior antibacterial activity when tested against both S. aureus and E. coli. The microstructure of the composite film become heterogeneous and rough after addition of TiO2 and cinnamaldehyde compare to control film. The findings of the present study may facilitate a re‐evaluation of the potential of using multiple compounds to prepare active edible films.

Viscose fabrics were modified with alginate and doped with copper ions, to investigate the effect of copper doping on their antibacterial and UV blocking properties. The modified fabrics were characterized using FTIR, UV spectroscopy, SEM and chromatometric analysis and their copper uptake properties were investigated. The antibacterial effect of the treatments was evaluated before and after repeated washings (up to 50 cycles). The resulting composite materials showed excellent antibacterial properties with up to 100 % reduction of bacteria, even from very low copper content, while alginate/copper treatment increased the UV radiation protection index by 261 %, offering a composite fabric with improved performance.

Development of ecofriendly packaging materials is still a challenging area. Researchers are continuously working to improve the mechanical and barrier properties of the different polymers which are used in the packaging industry. Selection of reinforcement and matrix for any composite are based upon end use applications. The novelty of the work is development of fully biodegradable, flexible, lightweight biocomposite by reinforcing needle punched flexible nonwoven viscose fabric to the PVA solution. The effect of PVA concentration and areal density of viscose fabric on the properties of prepared composite is examined. The composite thus prepared is assessed in terms of mechanical, thermal, breathability, and UV blocking properties. The nonwoven viscose‐PVA composite shows excellent improvement in tensile strength of 100% to 300% with respect to PVA film of equivalent concentration for two different areal densities of viscose fabric. The composite also exhibits improved thermal stability and UV blocking property with respect to parent components. However, a reduction in flexibility (with respect to PVA film) as well as breathability (with respect to viscose fabric) of the composite is observed. Based upon the improved performance of the viscose‐PVA composite in terms of mechanical properties, UV and water vapor permeability, it seems that the composite has a strong potential for application in the packaging sector as a flexible as well as biodegradable composite.

Two representative hemicelluloses, xylan and konjac glucomannan (KGM), were composited with 2,2,6,6-tetramethylpiperidine-1-oxyl radical-oxidized cellulose nanofibers (CNF), endowing the CNF-based nanocomposite films with enhanced strength, flexibility and UV blocking properties. Particularly, xylan and KGM were separately or simultaneously mixed with a CNF dispersion to obtain three kinds of CNF-based nanocomposite films: CNF-Xylan (CNF-X), CNF-KGM (CNF-K), and CNF-Xylan-KGM (CNF-XK). The compositing of KGM increased both the tensile stress and strain of the resulted film (tensile strength of 136 MPa for CNF-K at 10 wt% KGM with a strain of 6%, compared to a tensile strength of 106 MPa for the pure CNF film with a strain of approximately 1%). The improved strength and flexibility of the CNF-based nanocomposite films are attributed to the good permeation of KGM in CNF and the formation of intermolecular hydrogen bonds between KGM and CNF. On the other hand, due to the compositing of xylan, the CNF-based nanocomposite films CNF-X and CNF-XK showed good optical properties and interesting UV-blocking properties. In addition, CNF-based nanocomposite films showed lower water absorption capacity than pure CNF films. These results indicate the great potential of hemicellulose in the development of CNF-based films with enhanced unique performance.