Graft copolymerization of itaconic acid onto chitin and its properties

Natural bio-based monomers for biomedical applications: a review

In recent years, synthetic and semi-synthetic polymer materials have been widely used in various applications. Especially concerning biomedical applications, their biocompatibility, biodegradability, and non-toxicity have increased the interest of researchers to discover and develop new products for the well-being of humanity. Among the synthetic and semi-synthetic materials, the use of natural bio-based monomeric materials presents a possible novel avenue for the development of new biocompatible, biodegradable, and non-toxic products. The purpose of this article is to review the information on the role of natural bio-based monomers in biomedical applications. Increased eco-friendliness, biocompatibility, biodegradability, non-toxicity, and intrinsic biological activity are some of the attributes which make itaconic, succinic, citric, hyaluronic, and glutamic acids suitable potential materials for biomedical applications. Herein, we summarize the most recent advances in the field over the past ten years and specifically highlight new and interesting discoveries in biomedical applications. Natural origin acid-based bio-monomers for biomedical applications.

Salt-Free Dyeing of Modified Cotton through Graft Polymerization with Highly Enhanced Dye Fixation and Good Strength Properties

Modification of cotton fabric with 2-methacryloyloxyethyltrimethyl ammonium chloride (DMC) was achieved through free-radical initiated graft polymerization with K₂S₂O₈/NaHSO₃ as the initiator. Grafting of DMC was confirmed by ATR-IR of the modified cotton. The optimal grafting reaction conditions, including DMC dosage, mole ratio of initiator to DMC, temperature, and time, were determined by cation content and dye fixation results of the modified cotton. The modified fibers were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), and whiteness measurement. Salt-free dyeing of the modified cotton with commonly used C. I. Reactive Blue 19, C. I. Reactive Yellow 145, and C. I. Reactive Red 195 presented high fixation of 96.8%, 98.7%, and 97.3%, respectively. These results indicated that the modification is effective for changing the surface charge of the fiber and increasing the dye-fiber reactivity. The color fastness and strength property were still very satisfactory. With excellent properties, this dyeing method shows promise in real application for eliminating the usage of salt and reducing environmental pollution.

Chitosan Derivatives: Introducing New Functionalities with a Controlled Molecular Architecture for Innovative Materials

The functionalization of polymeric substances is of great interest for the development of innovative materials for advanced applications. For many decades, the functionalization of chitosan has been a convenient way to improve its properties with the aim of preparing new materials with specialized characteristics. In the present review, we summarize the latest methods for the modification and derivatization of chitin and chitosan under experimental conditions, which allow a control over the macromolecular architecture. This is because an understanding of the interdependence between chemical structure and properties is an important condition for proposing innovative materials. New advances in methods and strategies of functionalization such as the click chemistry approach, grafting onto copolymerization, coupling with cyclodextrins, and reactions in ionic liquids are discussed.

Fast microwave-assisted green synthesis of xanthan gum grafted acrylic acid for enhanced methylene blue dye removal from aqueous solution

In the present project, graft polymerization was employed to synthesis a novel adsorbent using acrylic acid (AA) and xanthan gum (XG) for cationic methylene dye (MB⁺) removal from aqueous solution. The XG was rapidly grafted with acrylic acid (CH₂=CHCOOH) under microwave heating. Fourier-transform infrared spectroscopy (FTIR), Proton Nuclear magnetic resonance spectroscopy (¹H NMR), scanning electron microscopy (SEM), X-ray diffraction (XRD) and Thermal gravimetric analysis (TGA) techniques were used to verify the adsorbent formed under optimized reaction conditions. Optimum reaction conditions [AA (0.4M), APS (0.05M), XG (2gL^-1), MW power (100%), MW time (80s)] offer maximum %G and %GE of 484 and 78.3, respectively. The removal ratio of adsorbent to MB⁺ reached to 92.8% at 100mgL^-1. Equilibrium and kinetic adsorptions of dyes were better explained by the Langmuir isotherm and pseudo second-order kinetic model respectively. The results demonstrate xanthan gum grafted polyacrylic acid (mw XG-g-PAA) absorbent had the universality for removal of dyes through the chemical adsorption mechanism.

Microwave assisted synthesis and characterization of sodium alginate-graft-poly(N,N'-dimethylacrylamide)

Modification of sodium alginate (NaAlg) was carried out using N,N'-dimethylacrylamide (DMAAm) as a monomer and azobisizobutyronitrile (AIBN) as an initiator under microwave irradiation. The effect of reaction conditions such as concentrations of DMAAm, AIBN, NaAlg as well as microwave power and temperature on grafting and grafting efficiency has been explored. Maximum grafting and grafting efficiency has been observed at 1h of grafting time, 0.291 M of DMAAm concentration, 500 W microwave irradiation power, 0.134 M of AIBN concentration, 75°C of reaction temperature and 0.5 g/dL of NaAlg concentration. The grafted copolymer has been characterized by FTIR, DSC, TGA, (13)C NMR, XRD, SEM, and GPC analysis. Cytotoxicity as standard MTT assay, apoptotic and necrotic effects of graft copolymer were investigated on L929 fibroblast cell. It has been found that the grafted copolymer is biocompatible and thermally more stable than the ungrafted alginate.

Gold-dotted hydroxyapatite nanoparticles as multifunctional platforms for medical applications

Hydroxyapatite nanoparticles decorated with gold dots, synthesized by a citrate mediated chemical method, enhance the osteogenic differentiation of HMSC.