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In the present work, cellulose nanocrystals (CNCs) composite films with suitable applicable capabilities were prepared by facilely incorporating glycerol (Gly) and poly(benzyl acrylate) (PBA). Chemical and morphological variations during the fabrication of the films were systematically characterized. The properties of modified CNCs composite films including UV blocking ability, mechanical strength and thermal properties were characterized to assess their applicable potentials. As a result, the composite films have good UV shielding property in UVC (220–280 nm) region and UVB (280–320 nm) region. The shielding performance of the modified film in the ultraviolet absorption region reached 92.77% to 95.49% respectively, without damaging the original chiral nematic structure of the films. Along with the modification, BACNC film improved the mechanical properties, presenting the tensile strength 16 times higher compared to pure CNCs film. The nanocomposite films proposed in this work showed promising potentials in broad fields, such as food preservation, medical protection, and surface coating applications. [ABSTRACT FROM AUTHOR]

The development of high-strength and intrinsic flame-retardant natural fiber-reinforced green composite (NFRGC) is a landmark for high-performance structural applications. This paper reports a biobased, high-performance, flame-retardant composite material based on diverse bio-resources. Tough and strong cellulose long filaments (CLFs) are combined with vanillin-derived epoxy (VDE) resin to achieve high strength and flame-retardant NFRGC. The green composite was fabricated using a simple hand lay-up and compression molding technique. The green composite showed a noteworthy increment of 100.9 % flexural strength and 346 % flexural modulus compared to the neat VDE resin. Interestingly, despite the highly flammable nature of CLF, the green composite passes a V-0 rating under the UL-94 test, indicating excellent flame-retardant characteristics. Additionally, the green composite demonstrated outstanding hydrophobicity with a water contact angle of 104.2° and good chemical stability in various acidic and organic solvents. The green composite's excellent mechanical and physical properties show its potential for high-strength and flame-retardant structural applications. [Display omitted] [ABSTRACT FROM AUTHOR]

The development of high-strength and intrinsic flame-retardant natural fiber-reinforced green composite (NFRGC) is a landmark for high-performance structural applications. This paper reports a biobased, high-performance, flame-retardant composite material based on diverse bio-resources. Tough and strong cellulose long filaments (CLFs) are combined with vanillin-derived epoxy (VDE) resin to achieve high strength and flame-retardant NFRGC. The green composite was fabricated using a simple hand lay-up and compression molding technique. The green composite showed a noteworthy increment of 100.9 % flexural strength and 346 % flexural modulus compared to the neat VDE resin. Interestingly, despite the highly flammable nature of CLF, the green composite passes a V-0 rating under the UL-94 test, indicating excellent flame-retardant characteristics. Additionally, the green composite demonstrated outstanding hydrophobicity with a water contact angle of 104.2° and good chemical stability in various acidic and organic solvents. The green composite's excellent mechanical and physical properties show its potential for high-strength and flame-retardant structural applications. [Display omitted] [ABSTRACT FROM AUTHOR]

Bio-composites are easy to manufacture and environmentally friendly, could reduce the overall cost and provide lightweight due to the low density of the natural fibers. In a bid to compete with the synthetic fiber reinforced composites, a single natural fiber composite may not be a good choice to obtain optimal properties. Hence, hybrid composites are produced by adding two or more natural fibers together to obtain improved properties, such as mechanical, physical, thermal, water absorption, acoustic and dynamic, among others. Regarding thermal stability, the composites showed a significant change by varying the individual fiber compositions, fiber surface treatments, addition of fillers and coupling agents. The glass transition temperature and melting point obtained from the thermomechanical analysis and differential scanning calorimetry are not the same values for several hybrid composites, since the volume variation was not always parallel with the enthalpy change. However, the difference between the temperature calculated from the thermomechanical analysis and differential scanning calorimetry was lower. Significantly, this critical reviewed study has a potential of guiding all composite designers, manufacturers and users on right selection of composite materials for thermal applications, such as engine components (covers), heat shields and brake ducts, among others. [ABSTRACT FROM AUTHOR]

Soil burial degradation was confirmed to be an efficient waste disposal method for the biodegradable materials with short service life, such as starch/poly (lactic acid) (PLA) composite. The biodegradation behavior about chemical and thermal properties of starch/PLA composite was analyzed by using X-ray photoelectron spectroscopy (XPS), infrared microscopy (IRM), differential scanning calorimetry (DSC), and thermal gravimetric analysis (TGA). XPS and IRM results indicated that the biodegradation of PLA occurred at the ester groups in PLA chains. XPS demonstrated the cleavage of C O linkages between glucose rings in starch. DSC and TGA results showed that the starch/PLA composite degraded faster than the pure PLA. During the soil burial degradation, the glass transition temperature of starch/PLA composite exhibited an obviously decrease while it had a slight variation for PLA. The thermal stability of starch/PLA composite shifted towards to that of PLA when they were subjected to soil burial for the same time. It is established that the starch can accelerate the degradation of PLA-based materials, which will enlarge the markets of biodegradable PLA materials used for short service life products. [ABSTRACT FROM AUTHOR]

To obtain a safe and biodegradable material for food packaging, this study developed a facile and green process of anchoring nisin onto oxidized cellulose through a simple Schiff base reaction for long-term antimicrobial active food packaging. To the best of our knowledge, this is the first report of such a packaging. The grafting reaction between the amino groups of nisin and the aldehyde groups of oxidized cellulose films was successfully established to obtained a nisin anchored cellulose films (NC) membrane; the structure was characterized with Fourier transform infrared spectroscopy, scanning electron microscopy, and thermogravimetric analysis. The NCs membrane had an outstanding transparent property of above 90% transmittance through 300 nm to 800 nm; while, the barrier properties against oxygen remain excellent. The thermal stability of the NCs membrane remained excellent and enabled an easier degradation than the original cellulose membrane. The NCs membrane displayed good antimicrobial activity against Alicyclobacillus acidoterrestris DSM 3922T in a long-term way, thus demonstrating good potential as food packaging material. The obtained results are promising and confirm the development of NCs membranes as green materials for food packaging. [ABSTRACT FROM AUTHOR]

In this work, chitin-curcumin based polyurethane elastomers (PUEs) were prepared by step growth polymerization technique using hydroxy terminated polybutadiene (HTPB), hexamethylene diisocyanate (HDI), chitin and curcumin. The molecular characterization was done by using FTIR and SS 1 HNMR techniques. The surface morphology and thermal stability was studied by scanning electron microscopy (SEM) and thermal gravimetric analysis (TGA), respectively. Degree of absorption and swelling characters were also determined in water as well as in DMSO. The crystalline behavior of prepared elastomers was checked by using X-ray diffraction (XRD) and differential scanning calorimeter (DSC). Results presented that crystallinity of elastomers increased by increasing the content of chitin due to formation of more ordered structure. [ABSTRACT FROM AUTHOR]

Abstract: The structural properties, thermal behaviour and mechanical properties of composites of chitosan (Ch) with nanoclay (montmorillonite, MMT) and/or nanoclays after surface modification have been characterized using scanning electron microscopy (SEM), atomic force microscopy (AFM), thermogravimetric analysis (TGA) and a tensile tests. The microstructure obtained by SEM and AFM microscopy for unmodified chitosan and its composites showed that particles are relatively well dispersed in the chitosan matrix. However, the increasing concentration of the chitosan solution from 1% to 2% decreases the homogeneity of the surface of the composites. In the case of chitosan composite with modified nanoclay (contains 25–30wt.% of octadecylamine), the lack of particles aggregates in polymer matrix independent of the concentration of chitosan solution was observed. Generally, addition of nanoclay after its surface modification improved the mechanical and thermal properties of the composite much more than montmorillonite without modification. [Copyright &y& Elsevier]

Abstract: Sodium alginate/sodium montmorillonite hybrid films were prepared by casting from the suspension of sodium alginate and different clay samples. Clay samples had been modified with a cationic surfactant, a cationic polymer, and a small polar molecule, respectively. Benzethonium chloride, polyethyleneimine and urea were used as clay modifiers. The composite films begin to disintegrate at a higher temperature and with less weight loss than the pure alginate films. This suggests an enhancement of the film thermal stability due to the modification of the alginate with clay samples. [Copyright &y& Elsevier]

Abstract: The chitin/gelatin composite membranes were prepared by mixing of chitin hydrogel with gelatin. The prepared composite membranes were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), mechanical, swelling, enzymatic degradation and thermal studies. The XRD pattern of the chitin/gelatin composite membranes showed almost the same pattern as α-chitin. The bioactivity studies of these chitin/gelatin membranes were carried out with the simulated body fluid solution (SBF) for 7, 14 and 21 days followed by the characterization with the scanning electron microscopy (SEM) and Energy Dispersive Spectrum (EDS) studies. The SEM and EDS studies confirmed the formation of calcium phosphate layer on the surface of chitin/gelatin membranes. Biocompatibility of the chitin/gelatin membrane was assessed using human MG-63 osteoblast-like cells. After 48h of incubation, it was found that the cells had attached and completely covered the membrane surface. Thus, the prepared chitin/gelatin membranes are bioactive and are suitable for cell adhesion suggesting that these membranes can be used for tissue-engineering applications. [Copyright &y& Elsevier]