New Hydrogels Based on Substituted Anhydride Modified Collagen and 2‑Hydroxyethyl Methacrylate. Synthesis and Characterization

Semi-interpenetrated networks were obtained by free radical polymerization/cross-linking of substituted anhydride modified collagen with 2-hydroxyethyl methacrylate (HEMA) in the presence of ammonium persulfate (APS) and <i>N</i>,<i>N</i>,<i>N</i>′,<i>N</i>′-tetramethyl ethylene diamine (TEMED). Substituted anhydride modified collagens, porous materials with vinyl groups, have been previously synthesized by reaction of soluble collagen with dimethyl maleic anhydride (DMA) or citraconic anhydride (CTA). The structure and physicochemical properties of the obtained hydrogels were investigated by Fourier transform infrared spectroscopy, scanning electron microscopy (SEM), and water retention studies. Thermal properties of substituted anhydride modified collagen and their corresponding hydrogels have been investigated by differential scanning calorimetry (DSC) in dried and hydrated states. The denaturation temperature (<i>T</i>_d), denaturation enthalpy, and glass transition temperature (<i>T</i>_g) have been determined, and they were found to be dependent on chemical composition, thermal history, and moisture content. The water states (free or bonded) in the hydrated samples were correlated with their swelling degree

Lignin Modification with Carboxylic Acids and Butyrolactone under Cold Plasma Conditions

The modification of organosolv lignin powder (ALCELL) with different carboxylic acids such as oleic, lactic, and butyric acids and butyrolactone under cold plasma discharge has been performed. The X-ray photoelectron spectroscopy (XPS), attenuated total reflectance Fourier transform infrared (ATR-FTIR), and ¹H NMR spectroscopy, scanning electron microscopy (SEM), and thermal methods (differential scanning calorimetry (DSC) and thermogravimetry (TG)) proved that the lignin modification took place. The structure, morphology and thermal properties are specific for each kind of product obtained. The modification degree determined on the basis of XPS data varies from 4 to 13% depending on reagent used. The significant changes in the thermal properties indicate that the modification by cold plasma affected also some bulk properties. This is the case mainly for modification with butyric acid and butyrolactone. It was concluded that the cold plasma modification is an efficient and eco-friendly technique able to produce new valuable products from lignin, widening its compatibility with various polymers and also its applications

Lactoferrin-Immobilized Surfaces onto Functionalized PLA Assisted by the Gamma-Rays and Nitrogen Plasma to Create Materials with Multifunctional Properties

Both cold nitrogen radiofrequency plasma and gamma irradiation have been applied to activate and functionalize the polylactic acid (PLA) surface and the subsequent lactoferrin immobilization. Modified films were comparatively characterized with respect to the procedure of activation and also with unmodified sample by water contact angle measurements, mass loss, X-ray photoelectron spectroscopy (XPS), attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR), atomic force microscopy (AFM), and chemiluminescence measurements. All modified samples exhibit enhanced surface properties mainly those concerning biocompatibility, antimicrobial, and antioxidant properties, and furthermore, they are biodegradable and environmentally friendly. Lactoferrin deposited layer by covalent coupling using carbodiimide chemistry showed a good stability. It was found that the lactoferrin-modified PLA materials present significantly increased oxidative stability. Gamma-irradiated samples and lactoferrin-functionalized samples show higher antioxidant, antimicrobial, and cell proliferation activity than plasma-activated and lactoferrin-functionalized ones. The multifunctional materials thus obtained could find application as biomaterials or as bioactive packaging films