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In this paper, chitosan (Chi) was successfully reacted with natural mono ketone namely, camphor (Cam), through a condensation reaction to obtain a novel Chi-Cam polymer. The encapsulation of Chi-Cam polymer into the cavity of β-cyclodextrin biopolymer by inclusion complex method, and the immobilization of TiO 2 NPs into Chi-Cam matrix by metal complex method were performed. A set of characterizations (XRD, FTIR, SEM, UV–Vis., optical band gap, Urbach energy, refractive index, and thermogravimetric analysis) were implemented to incorporate their properties with applications. It was not observed the existence of any strange peaks in diffractogram patterns of all prepared samples, confirming the proper preparation and high purity polymers. The crystalline index was found to be 69.41, 41.58, 58.25 and 44.2 % for Chi, Chi-Cam, polyrotaxane, and nanocomposite, respectively. High surface area, lowest pores size, and lowest pores volume were confirmed the micropores of composite, which also could provide more reactive sites, and enhancing the bioactivity. The tested Chi-Cam/TiO 2 NPs possessed the highest antimicrobial impact, followed by the Chi-Cam/β-CD towards pathogenic microbes. The highest % inhibition of biofilm formation by Chi-Cam, Chi-Cam/β-CD, and Chi-Cam/TiO 2 NPs was noted for S. aureus (40.05 %, 80.21 %, and 87.49 %), E. coli (38.56 %, 74.32 % and 83.32 %), P. aureginosa (32.12 %, 58.80 %, and 74.53 %), and C. albicans (13.69 %, 27.89 % and 70.89 %), respectively. The obtaining findings pave the route towards useful utilization of potential materials for biomedical applications. [ABSTRACT FROM AUTHOR]

Thermoplastic starch (TPS) is a widely studied biopolymer as an alternative to the use of conventional polymers. In this sense, the incorporation of fillers or reinforcements coming preferably from other substances of natural origin, can be an alternative to try to improve some mechanical and thermal properties of starch polymers. Thus, Kraft Lignin (KL), can be an excellent filler to be incorporated, since it presents mechanical and thermal properties and reduces the cost and weight of the final compounds. TPS films were prepared by casting using dimethyl sulfoxide (DMSO) as solvent and additives with 2, 4 and 8% KL. Characterization of TPS films and compositions with KL were carried out by Fourier-Transform Infrared Spectroscopy (FT-IR), Scanning Electron Microscope (SEM), Thermogravimetric Analysis (TGA), Dynamic Thermomechanical Analysis (DMTA), tensile testing and contact angle. Samples were also analyzed for biodegradation and for the ability to remove contaminants in water, Metil Orange (MO), by Ultraviolet-Visible Spectroscopy (UV–Vis). The FT-IR spectra of the films showed bands typical of functional groups derived from starch and lignin, with the intensity of these bands varying among the samples studied. Micrographs revealed slightly different morphologies among the films, but all showed irregular shapes with structures that appeared as plots. Increasing the percentage of KL led to an increase in contact angle values, showing a more hydrophobic behavior. In the TGA analysis, it was possible to observe a change in the main degradation event of the films for lower temperatures, especially of TPS – 4 and 8% KL compared to the TPS film. Films with KL had the peak of maximum degradation shifted to temperatures below the starch film, where the decrease in intensity of the main peak in the TPS - 4% KL and TPS - 8% KL samples demonstrates that there was less mass loss in the event. There was also in the percentage of residue as the addition of KL was increased The DMTA analyses allowed for the conclusion that presence of KL in TPS film allowed for an increase in its energy storage property, and that the loss modulus followed a decreasing order of storage modulus values to TPS - 8% KL from TPS. For the tensile strength property only TPS - 4% KL has significant improvement, and the elongation at break showed an increase for TPS – 4 and 8% KL compared to TPS. Samples showed a continuous and progressive biodegradation process, being completely biodegraded within 10 days. The monitoring of the ability to remove contaminants from water by UV–Vis, also showed promising results of compounds for this application. The best results were obtained, in most tests, for the TPS- 4% KL films. • Improvement in thermal and mechanical properties in TPS films with KL • The increase in the KL percentage led to a more hydrophobic behavior in TPS films. • Using of KL as a material of added value for improvement of the thermal properties of TPS • The presence of lignin slow down the biodegradation process in TPS films • The KL reduces the mass loss of the TPS film, and can be applied in controlled release. [ABSTRACT FROM AUTHOR]

Agar/polyacrylamide/quaternary ammonium silane-based (A/P/QAS-based) composite films were developed for food and biomedical packaging applications. The structural, optical, and surface morphological properties of the A/P and A/P/QAS composites were characterized by various characterization techniques in terms of thermogravimetric analysis, differential scanning calorimetry analyses, mechanical and rheological properties. Results showed that the 5% gravimetric loss (57.8–139.1 °C), glass transition temperature (179–189.9 °C) and tensile strength (35.2–47.8 MPa) of the prepared composites increased with increasing polyacrylamide content. The contact angle and water barrier properties of the composites were considerably improved by the addition of QAS. To compare WVP values of the A/P/QAS composite with neat AP composite films it reduced nearly 46% (2.45 to 1.32 × 10−9 g/m2 Pas). The A/P/QAS composites showed excellent antimicrobial properties against five different organisms. The Staphylococcus aureus exhibited highest 25 mm for gel and 18.1 mm for film of A/P/QAS composites. All the composites exhibited shear-thinning behavior, and their viscosity increased with increasing polyacrylamide content. The storage moduli of the prepared hydrogel composites were in the range of 5000–10,600 Pa at 1 rad/s and increased continuously over the entire frequency range. The dynamic rheological properties of A/P and A/P/QAS composites indicated that the prepared composites had good mechanical strength. Biopolymer based A/P and A/P/QAS composite films are suitable for green composite packaging applications. • Novel ternary composites were prepared from agar, polyacrylamide and QAS. • Addition of polyacrylamide improved the rheological properties. • QAS added composites exhibited excellent antimicrobial properties. • Thermal properties and water barrier properties were improved by QAS. • Increasing polyacrylamide content increased the dynamic viscosity [ABSTRACT FROM AUTHOR]

The aim of this study was to produce new nanocomposites with antimicrobial, antioxidant and anticancer properties that can be used in biomedical research based on carboxymethyl cellulose (NaCMC) biopolymer. First, poly(2-oxo-2-(pentafluorophenoxy)ethyl-2-methylprop-2-enoate) (PPFMA) was synthesized and characterized by FTIR and NMR techniques. It was then blended with NaCMC by in situ/hydrothermal method to produce a semi-synthetic functional material. Changes in the FTIR data of the blend and the single Tg value from DSC confirmed the compatibility of the blend. To enhance the thermal and biological properties of the NaCMC-PPFMA blend, biosynthesized Ag-ZnONPs were hydrothermally incorporated into the blend at different weight ratios. The prepared materials were characterized by SEM, EDX, TEM, XRD and FTIR. The thermal stability of the materials was determined by thermogravimetric analysis (TGA), and glass transition temperatures (Tg) was determined by differential scanning calorimeter (DSC). The oxidant, antioxidant, antimicrobial, and cytotoxic properties of PPFMA, Ag-ZnONPs, PPFMA-NaCMC blend, and nanocomposites were investigated in detail. The total oxidant state (TOS) value of the NaCMC-PPFMA blend, which was 0.72 μmol equivalent H 2 O 2 /L, increased to 7.2–10.4 μmol equivalent H 2 O 2 /L with the addition of Ag-ZnONPs. Ag-ZnONPs decreased total antioxidant state (TAS) levels of the nanocomposites while increasing their oxidant activity. Therefore, an increase in the antimicrobial activity of the nanocomposites was observed. Adding Ag-ZnONPs to the NaCMC-PPFMA blend increased the thermal stability by 22 °C and the Tg value by 9 °C. Finally, the potential of Ag-ZnONPs containing nanocomposites in wound healing therapies was examined. The findings suggest that nanocomposites prepared by incorporating Ag-ZnONPs into the semi-synthetic NaCMC-PPFMA blend can be a source of bio-safe raw materials and can be used as potential wound healers. [ABSTRACT FROM AUTHOR]

This study investigates the influence of various fillers on the properties of carrageenan, a natural polymer derived from red seaweed. Despite its potential for enhanced biocomposite film development, carrageenan faces challenges related to strength. The incorporation of nanoclay into the carrageenan film resulted in a significant increase in film thickness from 0.026 to 0.068 mm. The UV light transmission value for the carrageenan film alone was measured at 30.9 %, whereas films containing 5 wt% of Tetraethyl orthosilicate (TEOS), 3-Aminopropyltriethoxysilane (APTES), and nanoclay exhibited reduced transmission values of 23 %, 18 %, and 1 %, respectively. Notably, the tensile strength of the unfilled carrageenan film was 38.4 MPa, which increased to 38.6, 57, and 60 MPa upon the addition of 3 wt% of nanoclay, APTES, and TEOS fillers, respectively. All fillers contributed to improved tensile strength, with TEOS demonstrating the highest enhancement. The optimal filler content was determined to be 3 wt%. Regarding thermal properties, films containing TEOS displayed higher thermal stability compared to those with APTES, while films incorporating nanoclay exhibited the lowest stability. Findings provide insights into the effects of different fillers on the mechanical, physical and thermal properties of carrageenan films, supporting the development of improved biocomposite materials suitable for application in food packaging. • Nanoclay, TEOS and APTES were used to modify of the carrageenan film. • Silane-containing films have good interaction with the biopolymer matrix. • Nanoclay-containing films performed excellent in the case of UV transmittance. • Nanoclay-containing films showed better contribution to thermal stability. • Incorporation of the fillers in biopolymers resulted in higher tensile strength. [ABSTRACT FROM AUTHOR]

The modulation of structural fibrous protein and polysaccharide biopolymers for the design of biomaterials is still relatively challenging due to the non-trivial nature of the transformation from a biopolymer's native state to a more usable form. To gain insight into the nature of the molecular interaction between silk and cellulose chains, we characterized the structural, thermal and morphological properties of silk-cellulose biocomposites regenerated from the ionic liquid, 1-ethyl-3-methylimidazolium acetate (EMIMAc), as a function of increasing coagulation agent concentrations. We found that the cellulose crystallinity and crystal size are dependent on the coagulation agent, hydrogen peroxide solution. The interpretation of our results suggests that the selection of a proper coagulator is a critical step for controlling the physicochemical properties of protein-polysaccharide biocomposite materials. [ABSTRACT FROM AUTHOR]

• Water-soluble myofibrillar protein–pectin complex was formed. • Enhanced physical stability around protein pI can be obtained at 1 wt% protein. • Viscosity increased with pectin addition, but decreased with pH dropping. • The elastic network may be due to the electrostatic complexation and entangling. • Denaturation temperature of myosin and actin can be increased by forming complex. This study tested the potential of forming soluble complex with pectin (PEC) on enhancing physical stability of water-soluble myofibrillar protein (WSMP) near the isoelectric point (pI, pH 5.00–5.50). After incorporation of PEC at the mixing ratio of 10:1 and 5:1, WSMP suspension maintained transparent state at 0.05 wt% while a homogeneous monophase at 1.00 wt% around pI, indicating the formation of soluble WSMP–PEC complex. When mixing the two biopolymers, charge neutralization was observed, revealing the electrostatic attraction between positively charged patches of WSMP and negatively charged carboxyl sites of PEC. Steady shear results showed a reduced viscosity of WSMP–PEC complex when dropping the pH to 5.00, this may be related to the declined biopolymer net charge and water trapping. Oscillatory data suggest the formation of highly-interconnected network in soluble WSMP–PEC complex, thus decreasing pH or biopolymer ratio can enhance their interactions and thereby lead to stronger and more stable microstructure. Thermal denaturation temperature of WSMP was significantly enhanced through the formation of WSMP–PEC soluble complexes. Overall, complexation with PEC improved the colloidal and thermal stability of WSMP around the pI, which evidenced the potential of applying tailor designed protein-polysaccharide complex in formulating muscle protein-based beverages. [ABSTRACT FROM AUTHOR]

In recent decades, research into biomaterials such as silk or cellulose has rapidly expanded due to their abundance, low cost, and tunable morphological as well as physicochemical properties. Cellulose is appealing due to its crystalline and amorphous polymorphs while silk is attractive due to its tunable secondary structure formations which is made up of flexible protein fibers. When these two biomacromolecules are mixed, their properties can be modified by changing their material composition and fabrication methodology, e.g., solvent type, coagulation agent, and temperature. Reduced graphene oxide (rGO) can be used to increase molecular interactions and stabilization of natural polymers. In this study, we sought to determine how small amounts of rGO affect the carbohydrate crystallinity and protein secondary structure formation as well as physicochemical properties and how they affect overall ionic conductivity of cellulose-silk composites. Properties of fabricated silk and cellulose composites with and without rGO were investigated using Fourier Transform Infrared Spectroscopy, Scanning Electron Microscopy, X-Ray Scattering, Differential Scanning Calorimetry, Dielectric Relaxation Spectroscopy, and Thermogravimetric Analysis. Our results show that addition of rGO influenced morphological and thermal properties of cellulose-silk biocomposites, specifically through cellulose crystallinity and silk β-sheet content which further impacted ionic conductivity. [ABSTRACT FROM AUTHOR]

In order to diversify the number of applications for poly[( R )-3-hydroxyalkanoates] (PHAs), methods must be developed to alter their physical properties so they are not limited to aliphatic polyesters. Recently we developed Escherichia coli LSBJ as a living biocatalyst with the ability to control the repeating unit composition of PHA polymers, including the ability to incorporate unsaturated repeating units into the PHA polymer at specific ratios. The incorporation of repeating units with terminal alkenes in the side chain of the polymer allowed for the production of random PHA copolymers with defined repeating unit ratios that can be chemically modified for the purpose of tailoring the physical properties of these materials beyond what are available in current PHAs. In this study, unsaturated PHA copolymers were chemically modified via thiol-ene click chemistry to contain an assortment of new functional groups, and the mechanical and thermal properties of these materials were measured. Results showed that cross-linking the copolymer resulted in a unique combination of improved strength and pliability and that the addition of polar functional groups increased the tensile strength, Young's modulus, and hydrophilic profile of the materials. This work demonstrates that unsaturated PHAs can be chemically modified to extend their physical properties to distinguish them from currently available PHA polymers. [ABSTRACT FROM AUTHOR]