In this study, we developed sodium alginate-chitosan hydrogels using a microwave-assisted synthesis method, aligning with green chemistry principles for enhanced sustainability. This eco-friendly approach minimizes chemical use and waste while boosting efficiency. A curcumin:2-hydroxypropyl-β-cyclodextrin complex was incorporated into the hydrogels, significantly increasing the solubility and bioavailability of curcumin. Fourier Transform Infrared Spectroscopy (FTIR) analysis confirmed the structure and successful incorporation of curcumin, in both its pure and complexed forms, into the polymer matrix. Differential scanning calorimetry revealed distinct thermal transitions influenced by the hydrogel composition and physical cross-linking. Hydrogels with higher alginate content had higher swelling ratios (338%), while those with more chitosan showed the lowest swelling ratios (254%). Scanning Electron Microscopy (SEM) micrographs showed a porous structure as well as successful incorporation of curcumin or its complex. Curcumin release studies indicated varying releasing rates between its pure and complexed forms. The chitosan-dominant hydrogel exhibited the slowest release rate of pure curcumin, while the alginate-dominant hydrogel exhibited the fastest. Conversely, for curcumin from the inclusion complex, a higher chitosan proportion led to the fastest release rate, while a higher alginate proportion resulted in the slowest. This study demonstrates that the form of curcumin incorporation and gel matrix composition critically influence the release profile. Our findings offer valuable insights for designing effective curcumin delivery systems, representing a significant advancement in biodegradable and sustainable drug delivery technologies.

This study investigated the influence of acrylonitrile-butadiene rubber (NBR) at 5 and 15 phr on the properties of silica-filled styrene-butadiene /polyisoprene (SBR/NR) rubber blends intended for boot tread production. Fourier Transform Infrared Spectroscopy evaluated the performance of the resulting SBR/NR/NBR composites with Attenuated Total Reflectance (FTIR-ATR), which confirmed interactions between the rubber matrix and the silica filler. In addition, changes in thermal and mechanical properties, as well as cross-linking parameters, were systematically examined. Differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) are used to provide a comprehensive understanding of the structural, thermal, and mechanical behavior of silica-reinforced SBR/NR/NBR composites. The rheological characteristics of the tested composites were examined as a function of the mixture ratio. Atomic force microscopy (AFM) revealed variations in the sample’s surface roughness and morphology with varying rubber blend ratios. The findings confirmed that incorporating NBR improves filler dispersion, increases cross-link density, and enhances mechanical properties, including hardness and tensile strength, while also influencing thermal stability and curing behavior. The results suggest the potential of these composites for reliable, efficient sole manufacturing in the footwear industry, where durability, strength, and processability are critical requirements.

The goal of this study was to synthesize chemically cross-linked copolymeric hydrogels based on vinylpyrrolidone monomer and vinyl acetate comonomer, with varying crosslinker content (ethanediol dimethacrylate) using the free radical polymerization mechanism, as well as to characterize them. Surface morphology was conducted using scanning electron microscopy (SEM). SEM micrographs reveal macroporous, amorphous-crystalline crosslinked structures of p(VP/VA) copolymers with an average pore diameter in the swollen state ranging approximately from 50 mm to 100 mm. DSC method was applied to detect the glass transition and melting temperatures of the p(VP/VA) copolymers. The obtained data indicates good comonomers miscibility within the homogenous polymer network and enhanced thermal stability (up to about 130 °C), which increases with increasing crosslinking density. A swelling study was conducted to assess the copolymer behaviour in solutions of different pH values. The highest equilibrium swelling ratio value (ae =123.42) was achieved for the sample with 2.0 mol% of crosslinker in alkaline solution with a pH value of 8. The lowest swelling capacity (ae =14.42) was observed for the sample with 3.0 mol% of crosslinker in an acidic medium (pH=2.0). These thermosensitive hydrogels showed also pH sensitivity

In this work, a comparative investigation of the hydrolytic and thermal stability of urea- formaldehyde (UF) resins modified with chitosan (UF/H) and zeolite (UF/Z) was performed. Zeolite ZSM-5 and chitosan were used to modify the in situ synthesized UF resin with a low formaldehyde/urea (FA/U) molar ratio (0.8), to reduce the free FA content in the UF resin. The disulfite method determined free and released FA from the synthesized composites. The modified UF composites were characterized using TG/DTG, and SEM. The results showed that chitosan and zeolite are good scavengers of FA from cross-linked modified UF composites. Both tested composites have the same content of free FA (0.06%). The UF/H composite is hydrolytically more stable because it has a lower content of released FA (2.52%), after acid hydrolysis, compared to the UF/Z composite (4.08%). On the other hand, the UF/Z composite proved to be thermally more stable (T5%= 205.4oC) than the UF/Z composite (T5%= 91.9oC).

The development of biodegradable ABA-type triblock copolymers with tailored thermo-mechanical performance requires precise control over polymer architecture and phase behavior. In this study, PLLA-based ABA triblock copolymers were synthesized using two structurally distinct, fully bio-based soft segments: poly(methyl ricinoleate) (PMR) and poly(1,3-propanediol) (PPD). To the best of our knowledge, this is the first report on PLLA triblock copolymers incorporating PMR as a renewable soft middle block. Hydroxyl-terminated PMR and PPD were employed as macroinitiators for the controlled ring-opening polymerization of L-lactide, enabling systematic variation in block composition and molecular weight. Structural characterization confirmed successful block formation, while thermal and mechanical analyses revealed pronounced differences in phase separation and structure–property relationships. Copolymers containing PMR exhibited enhanced phase separation, increased crystallinity of PLLA domains, and significantly improved elongation at break, attributed to the presence of pendant chains in the soft segment. In contrast, PPD-based copolymers showed reduced phase separation and more PLA-like mechanical behavior. These results demonstrate that the chemical architecture of bio-based soft segments plays a decisive role in governing the thermo-mechanical performance of PLLA-based triblock copolymers.