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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.

Core–shell polybutadiene‐graft‐polystyrene (PB‐g‐PS) graft copolymers with different ratios of PB to PS are synthesized by emulsion polymerization. Further, the PB‐g‐PS copolymers are blended with polypheylene ether (PPE) and PS to prepare PPE/PS/PB‐g‐PS blends. The effects of PB‐g‐PS copolymer structure and matrix composition on the morphological, mechanical properties, and deformation mechanism of the blends are studied. The results show that the synthesized submicrometer‐sized PB‐g‐PS copolymer has an excellent toughening efficiency, both the copolymer and PS are introduced into PPE resin to produce a ternary blend which is combined with high toughness and processing properties. The optimum toughening effect on PPE/PS matrix is observed at the core–shell weight ratio of 70/30 in PB‐g‐PS copolymer, and the impact strength of the blends increased from 101 to 550 J m−1. In addition, the dispersion pattern of rubber particles in the matrix gradually changes from uniform dispersion to aggregation as the core–shell ratio of PB‐g‐PS copolymers increases. On the other hand, with the increase of PPE content, the dispersion of rubber particles in PPE/PS matrix is improved, and the deformation mechanism is changed from cracking to a combination of crazing and shear yielding, which can lead to absorb more energy to achieve better toughness. The polybutadiene‐graft‐polystyrene (PB‐g‐PS) graft copolymers with different ratios of PB to PS are blended with polypheylene ether (PPE) and PS to prepare PPE/PS/PB‐g‐PS blends. It is found that the synthesized submicrometer‐sized PB‐g‐PS copolymer at the core–shell weight ratio of 70/30 has an excellent toughening efficiency, and the deformation mechanism of the blend is a combination of crazing and shears yielding.

This work aims to synthesize graft copolymers of chitosan and N-vinylimidazole (VI) with different compositions to be used as matrices for the immobilization of cysteine proteases—bromelain, ficin, and papain. The copolymers are synthesized by free radical solution copolymerization with a potassium persulfate-sodium metabisulfite blend initiator. The copolymers have a relatively high frequency of grafting and yields. All the synthesized graft copolymers are water-soluble, and their solutions are characterized by DLS and laser Doppler microelectrophoresis. The copolymers are self-assembled in aqueous solutions, and they have a cationic nature and pH-sensitivity correlating to the VI content. The FTIR data demonstrate that synthesized graft copolymers conjugate cysteine proteases. The synthesized copolymer adsorbs more enzyme macromolecules compared to non-modified chitosan with the same molecular weight. The proteolytic activity of the immobilized enzymes is increased up to 100% compared to native ones. The immobilized ficin retains up to 97% of the initial activity after a one-day incubation, the immobilized bromelain retains 69% of activity after a 3-day incubation, and the immobilized papain retains 57% of the initial activity after a 7-day incubation. Therefore, the synthesized copolymers can be used as matrices for the immobilization of bromelain, ficin, and papain.

Polysaccharide-based amphiphilic copolymers self-assemble in water to form micelle-like structures. They are expected to be used as nanocarriers in the biomedical field owing to their biocompatibility, biodegradability, and low toxicity. α-1,3-Glucan is a water-insoluble glucose homopolymer that can be generated through environmentally friendly enzymatic polymerization and easily purified without using organic solvents. Thus, it has attracted attention as a new bio-based material. In this study, we developed new nanomicelles based on α-1,3-glucan. Glycosyltransferase I from Streptococcus mutans was used to synthesize α-1,3-glucan, and a series of amphiphilic α-1,3-glucan-based graft copolymers (α-1,3-glucan-g-PLA) were synthesized with different L-Lactide supply ratios in the ionic liquid BmimCl. The results of FT-IR, 1H NMR, 13C NMR, XRD, and TGA verified that the reaction proceeded successfully. These amphiphilic α-1,3-glucan derivatives with low critical micelle concentrations can self-assemble to form core–shell structural micelles of various sizes (approximately 57–125 nm) in water. Furthermore, the self-assembled micelles were investigated as drug carriers using prednisone acetate (PA) as a model drug, and their sustained drug release behavior for 9 days was confirmed. These results revealed that the synthesized self-assembled micelles have promising potential as new carriers for the efficient delivery of hydrophobic drugs.

Self-assembled nanoparticles formed with amphiphilic block or graft copolymers are being extensively studied for their use in a variety of biological and industrial applications, including targeted drug delivery. This study reports a novel strategy to tune the structure of self-assembled nanoparticles for enhancing the cellular uptake by varying the hydrophilic ratio of amphiphilic graft copolymers. We synthesized poly(aspartic acid) (PAsp) substituted with octadecyl chains (C18) at varying degrees of substitution (DS), ranging from 4.5 to 37.5 mol%, which could form self-assemblies in an aqueous solution. As the DS increased, a morphological transition was observed—from spherical assemblies (DS 4.5 and 9.1) to rod-like (DS 19.0), vesicular (DS 25.7), and lamellar-like structures (DS 37.6). Further, Trans-Activator of Transcription (TAT) as the cell penetrating peptide to the synthesized amphiphilic graft copolymers leads to an enhanced cellular uptake of the biomimetic self-assembly. In particular, the lamellar-like self-assemblies resulted in a 1.3-fold increase of cellular uptake, as compared to the spherical self-assemblies, and a 3.6-fold increase, as compared to the vesicles. Therefore, tuning the structure of poly(aspartic acid)s’ self-assemblies was proven as an effective strategy to enhance the cellular uptake, while minimizing invasive cell damage. This new strategy to tune the morphologies of self-assemblies will serve to improve the cell penetrating activity for targeted drug delivery.

Poly(ethylene oxide)-poly(ε-caprolactone) (PEO-PCL) is a family of block (or graft) copolymers with several biomedical applications. These types of copolymers are well-known for their good biocompatibility and biodegradability properties, being ideal for biomedical applications and for the formation of a variety of nanosystems intended for controlled drug release. The aim of this review is to present the applications and the properties of different nanocarriers derived from PEO-PCL block and graft copolymers. Micelles, polymeric nanoparticles, drug conjugates, nanocapsules, and hybrid polymer-lipid nanoparticles, such as hybrid liposomes, are the main categories of PEO-PCL based nanocarriers loaded with different active ingredients. The advantages and the limitations in preclinical studies are also discussed in depth. PEO-PCL based nanocarriers could be the next generation of delivery systems with fast clinical translation. Finally, current challenges and future perspectives of the PEO-PCL based nanocarriers are highlighted.

Graphene conductive inks have attracted significant attention in recent years due to their high conductivity, corrosion resistance, and environmentally friendly nature. However, the dispersion of graphene in aqueous solution is still challenging. In this work, we synthesized an amphiphilic graft copolymer, polyvinyl alcohol-g-polyaniline (PVA-g-PANI), and studied the graphene dispersion prepared with the graft copolymer by high-speed shear dispersion. The amphiphilic graft copolymer can be used as a stabilizer and adhesive agent in graphene dispersion. Given the steric hindrance of the graft copolymer, the stability of graphene dispersion is improved by decreasing the probability of π–π stacking. PVA-g-PANI has a better stability on graphene dispersion than carboxymethylcellulose sodium (CMC-Na) and a mixture of PVA and PANI. The graft copolymer has only a slight effect on the conductivity of graphene dispersion due to the existence of conductive PANI, which is beneficial for preparing the graphene dispersion with good conductivity and adhesion. Graphene dispersion is well-adapted to screen printing and is very stable with regard to the sheet resistance bending cycle.

The melt-free radical grafting of glycidyl methacrylate (GMA) onto poly (lactic acid) (PLA) with styrene (St), α-methylstyrene (AMS), and epoxy resin (EP) as comonomers in a twin-screw extruder was used to prepare PLA-g-GMA graft copolymers. The prepared graft copolymers were then used as compatibilizers to prepare PLA/PPC/PLA-g-GMA blends by melt blending with PLA and polypropylene carbonate (PPC), respectively. The effects of different comonomers in the PLA-g-GMA graft copolymers on the thermal, rheological, optical, and mechanical properties and microstructure of the blends were studied. It was found that the grafting degree of PLA-g-GMA graft copolymers was increased to varying degrees after the introduction of comonomers in the PLA-g-GMA grafting reaction system. When St was used as the comonomer, the grafting degree of the PLA-g-GMA graft copolymer increased most significantly, from 0.8 to 1.6 phr. St as a comonomer also most improved the compatibility between PLA and PPC, and the haze of the blends was reduced while maintaining high transmittance. In addition, the PLA-g-GMA graft copolymer with the introduction of St as a comonomer significantly improved the impact toughness of the blends, while the thermal stability and tensile strength of the blends remained largely unchanged.

The current study utilized a green synthesis where microwave-assisted free radical technique was applied for economical synthesis of a novel biocompatible polymethyl methacrylate grafted moringa gum amphiphilic graft copolymer, focusing on optimization based on percentage yield, percentage grafting, and intrinsic viscosity was performed, and analytical characterizations confirmed successful grafting. The copolymer demonstrated surfactant-like properties, as evidenced by the determined critical micelle concentration (CMC). Evaluation of its impact on poorly water-soluble drugs, simvastatin, and metronidazole benzoate, revealed efficient release within 60 min. Safety assessments, including In vitro assessments like hemocompatibility, bactericidal activity, fish toxicity, and in vivo evaluations such as oral toxicity, and wound repair studies and cell toxicity studies indicated the safety profile of prepared graft copolymer and explored its potential as a biopolymer for pharmaceutical delivery and tissue regrowth platform. Graphical abstract

Graft gelatin and poly(methyl methacrylate) copolymers were synthesized in the presence of the tributylborane—2,5-di-tert-butyl-p-benzoquinone (2,5-DTBQ) system. The molecular weight parameters and morphology of the polymer indicate that it has a cross-linked structure. Obtained data confirm the simultaneous formation of a copolymer in two ways: “grafting from” and “grafting to”. It leads to the cross-linked structure of a copolymer. This structure was not obtained for copolymers synthesized in the presence of other initiating systems: azobisisobutyronitrile; tributylborane; azobisisobutyronitrile and tributylborane; azobisisobutyronitrile, tributylborane, and 2,5-di-tert-butyl-p-benzoquinone. In these cases, the possibility of the formation of the copolymer, simultaneously in two ways, was excluded. Graft gelatin and poly(methyl methacrylate) copolymers synthesized in the presence of the tributylborane—2,5-di-tert-butyl-p-benzoquinone system are promising in terms of their use in scaffold technologies due to the three-dimensional mesh structure, providing a high regenerative potential of materials.