Properties Of Copolymers Research Articles

Enhancing the Encapsulation Performances of Liposomes for Amphiphilic Copolymers by Computer Simulations.

Liposomes, which encapsulate drugs into an inner aqueous core and demonstrate high drug-loading capacity, have attracted considerable interest in the field of drug delivery. Herein, the encapsulation processes for amphiphilic copolymers within liposomes have been investigated systematically to enhance the encapsulation capacity and optimize the structures using dissipative particle dynamics simulations. The results indicate that the physicochemical properties of lipids, receptors, and amphiphilic copolymers collectively determine the encapsulation behaviors of liposomes. Adjusting the hydrophobic interaction between hydrophobic tails of lipids (receptors) and hydrophobic blocks of copolymers, along with modulating the specific interaction between ligands and the functional head groups of receptors, can lead to various encapsulation capacities. Significantly, a medium hydrophobic interaction strength or a strong specific interaction is conducive to achieving a higher degree of encapsulation for amphiphilic copolymers. Furthermore, varying the key parameters, such as the hydrophobic interaction, the specific interaction, as well as the concentrations of lipids and receptors, can induce seven typical aggregate structures: heterogeneous, fully encapsulated, partially encapsulated, saturated-encapsulated, unsaturated-encapsulated, multilamellar, and column-like structures. The final phase diagrams are also constructed to provide a guideline for designing various structures of liposomes encapsulated with amphiphilic copolymers. These results significantly contribute to the illumination of strategies for the rational construction of the self-assembly system that facilitates the efficient encapsulation of amphiphilic copolymers within the inner aqueous core of liposomes, thereby providing valuable insights into the optimal design of liposome carriers for future biomedical applications.

Influence of hydrogen bonding interactions, entanglement, and covalent crosslinking on the viscoelasticity of acrylic viscoelastomers containing urea group

The structure–property relationship of acrylic clear viscoelastomer films (acrylic CVFs) as foldable optical clear adhesives (OCAs) has always been unclear. In our work, a series of acrylic CVFs with different hydrogen-bonding interactions (H-bondings) and cross-linking densities (namely, CL-H-copolymers) were synthesized. The effects of entanglement, H-bonding, and covalent crosslinking on the recovery and adhesive properties of CL-H copolymers were analyzed by rheology, equilibrium swelling, and tensile stress–strain tests (tensile tests). The structural parameter Mx/MeH was obtained by combining the affine deformation model, the Flory-Rehner equation, and the UCM-Gent model, where Mx is the molecular weight between covalent crosslinkers and MeH is the a physical crosslinking molecular weight affected by H-bondings. The experimental results showed that the CL-H-copolymers had an obvious dependence on Mx/MeH. Recovery properties tended to stabilize (>90 %) at Mx/MeH < 1, while adhesion strengths continued to decrease with decreasing Mx/MeH. This conclusion and methodology are instructive for the design of foldable OCAs with high elasticity and high adhesion performance.

Hydrogel granular systems for controlled release based on (co)polymers of 2-hydroxyethyl methacrylate with polyvinylpyrrolidone (a review)

The development of polymer carriers for systems of prolonged and controlled release of substances, particularly drugs, into the action environment is a relevant task in polymer chemistry and technology. This aims to solve the problem of reducing the effective dose of a medical drug administered into the body of a person or animal. The latest achievements in the field of creating such carriers in the form of spherical particles based on 2-hydroxyethyl methacrylate and polyvinylpyrrolidone (co)polymers are analyzed and summarized. The working principles and advantages of such systems are described. The research of the synthesis regularities, structure, properties and perspectives of application of granular hydrogels based on 2-hydroxyethyl methacrylate and its copolymers with polyvinylpyrrolidone was analyzed. The mixture of decanol and cyclohexanol as a solvent for the monomer phase is substantiated. Based on the analysis of kinetic studies, the optimal technological parameters for the suspension polymerization of 2-hydroxyethyl methacrylate with polyvinylpyrrolidone were selected, and the possibility of regulating the dispersion characteristics of copolymers via changes in the technological synthesis modes was confirmed. The results of studies on the sorption-desorption properties of copolymers concerning model substances and drugs are described. The possibility of directed regulation of sorption capacity and drug release rate through changes in copolymer composition was confirmed. Methods for increasing the sorption capacity of hydrogels for drugs are proposed.

Electrical and Dielectrical Properties of Composites Based on Alumina and Cyclic Olefin Copolymers.

Understanding the performance of polymer dielectrics at different temperatures is becoming increasingly important due to the rapid development of electric cars, electromagnetic devices, and new energy production solutions. Cyclic olefin copolymers (COCs) are an attractive material due to their low water absorption, good electrical insulation, long-term stability of surface treatments, and resistance to a wide range of acids and solvents. This work focused on the dielectric and electrical properties of cyclic olefin copolymer (COC)/Al2O3 composites over a wide range of temperature and frequency domains, from room temperature to cryogenic temperatures (around 125 K). Permittivity, electrical conductivity, and electrical modulus are given consideration. A composite of up to 50% Al2O3 mixed with COC was prepared via a conventional melt-blending method. The final samples were formed in sheets and processed using injection and extrusion moldings. It was found that formulations with Al2O3 concentrations ranging from 10 to 50% resulted in higher electrical conductivity while maintaining the viscosity of the composite at a level acceptable for polymer-processing machinery. Our data show that COC/alumina composites present substantial potential as materials for high-frequency applications, even at the regime of cryogenic temperatures.

Exploring the Application of Advanced Chromatographic Methods to Characterize the Surface Physicochemical Properties and Transition Phenomena of Polystyrene-b-poly(4-vinylpyridine)

The linear diblock copolymer polystyrene-b-poly(4-vinylpyridine) (PS-P4VP) is an important copolymer recently used in many applications such as optoelectronics, sensors, catalysis, membranes, energy conversion, energy storage devices, photolithography, and biomedical applications. (1) Background: The surface thermodynamic properties of PS-P4VP copolymers are of great importance in many chemical and industrial processes. (2) Methods: The inverse gas chromatography (IGC) at infinite dilution was used for the experimental determination of the retention volumes of organic solvents adsorbed on copolymer surfaces as a function of temperature. This led to the variations in the free energy of interaction necessary to the evaluation of the London dispersive and polar acid–base surface energies, the polar enthalpy and entropy, the Lewis acid–base constants, and the transition temperatures of the PS-P4VP copolymer. (3) Results: The application of the thermal Hamieh model led to an accurate determination of the London dispersive surface energy of the copolymer that showed non-linear variations versus the temperature, highlighting the presence of two transition temperatures. It was observed that the Lewis acid–base parameters of the copolymer strongly depend on the temperature, and the Lewis base constant of the solid surface was shown to be higher than its acid constant. (4) Conclusions: An important effect of the temperature on the surface thermodynamic properties of PS-P4VP was proven and new surface correlations were determined.

Novel Bis(4-aminophenoxy) Benzene-Based Aramid Copolymers with Enhanced Solution Processability.

Aramid copolymers have garnered significant interest due to their potential applications in extreme environments such as the aerospace, defense, and automotive industries. Recent developments in aramid copolymers have moved beyond their traditional use in high-strength, high-temperature resistant fibers. There is now a demand for new polymers that can easily be processed into thin films for applications such as electrical insulation films and membranes, utilizing the inherent properties of aramid copolymers. In this work, we demonstrate two novel aramid copolymers that are capable of polymerizing in polar organic solvents with a high degree of polymerization, achieved by incorporating flexible bis(4-aminophenoxy) benzene moieties into the chain backbone. The synthesized MBAB-aramid and PBAB-aramid have enabled the fabrication of exceptionally thin, clear films, with an average molecular weight exceeding 150 kDa and a thickness ranging from 3 to 10 μm. The dynamic mechanical analysis (DMA) and thermogravimetric analysis (TGA) reveal that the thin films of MBAB-aramid and PBAB-aramid exhibited glass transition temperatures of 270.1 °C and 292.7 °C, respectively, and thermal decomposition temperatures of 449.6 °C and 465.5 °C, respectively. The mechanical tensile analysis of the 5 μm thick films confirmed that the tensile strengths, with elongation at break, are 107.1 MPa (50.7%) for MBAB-aramid and 113.5 MPa (58.4%) for PBAB-aramid, respectively. The thermal and mechanical properties consistently differ between the two polymers, which is attributed to variations in the linearity of the polymer structures and the resulting differences in the density of intermolecular hydrogen bonding and pi-pi interactions. The resulting high-strength, ultra-thin aramid materials offer numerous potential applications in thin films, membranes, and functional coatings across various industries.

Dissipative Particle Dynamics Study on Interfacial Properties of Ternary H-Shaped Copolymer–Homopolymer Blends

Dissipative particle dynamics (DPD) simulations is used to study the effect of Am/2BmAm/2 and H-shaped (Am/4)2Bm(Am/4)2 block copolymers on the interfacial properties of ternary blends. Our simulations show the following: (i) The capacity of block copolymers to diminish interfacial tension is closely linked to their compositions. With identical molecular weights and concentrations, H-shaped block copolymers outperform triblock copolymers in mitigating interfacial tension. (ii) The interfacial tension within the blends correlates positively with the escalation in H-shaped block copolymer molecular weight. This correlation suggests that H-shaped block copolymers featuring a low molecular weight demonstrate superior efficacy as compatibilizers when contrasted with those possessing a high molecular weight. (iii) Enhancing the concentration of H-shaped block copolymers fosters their accumulation at the interface, leading to a reduction in correlations between immiscible homopolymers and a consequent decrease in interfacial tension. (iv) As the length of the homopolymer chains increases, there is a concurrent elevation in interfacial tension, suggesting that H-shaped block copolymers perform more effectively as compatibilizers in blends characterized by shorter homopolymer chain lengths. These findings elucidate the associations between the efficacy of H-shaped block copolymer compatibilizers and their specific molecular characteristics.

Engineering Shape to Overcome Contraction: The Role of Polymer-Collagen Hybrids in Advanced Dermal Substitutes.

Collagen gels are the standard dermal equivalents par excellence, however the problem of rapid cell-mediated contraction remains unresolved. Therefore, the development of hybrid constructs (HCs) based on collagen and polymeric scaffolds is proposed to address the mechanical instability that usually limits the formation of new, functional tissue. Equally important, these synthetic structures should be temporary (degradable) while ensuring that cells are well-adapted to the new extracellular environment. In this study, we screened a library of scaffolds made of various polymers, including homopolymers of polycaprolactone (PCL) and poly D,L-lactide (PLA50), their blends (PCL/PLA50), and copolymers (poly(D,L-lactide-co-caprolactone), PCLLA50) to prepare HCs in a layer-by-layer fashion. The properties of polymers and copolymers along with their processability by electrospinning and 3D-printing were evaluated. Then, we assessed the HCs resistance toward cell-mediated contraction as well as the degradation of the polymeric scaffolds. Our results indicate that scaffolds with higher PLA50 content (e.g., PLA50 100%, PCL/PLA50 or PCLLA50, both at 50/50 caprolactone-to-D,L-lactide molar ratio) presented more drawbacks in terms of handleability and processing, while those with greater PCL presence showed structural steadiness and ease to use. All the scaffolds integrated well with the collagen gel to form the corresponding HCs. With few exceptions, the HCs demonstrated good resistance to cell-derived contraction over 3 weeks. Notably, HCs based on PCLLA50 90/10 (both versions, electrospun or 3D-printed) performed best, showing only a 5%-17% area reduction compared to the 93% observed in collagen-only gels. This copolymer displayed hydrolytic degradation depending on its shape, with up to 45% and 65% loss of molecular weight for the electrospun and 3D-printed forms, respectively, correlating with their progressive change in mechanical features. HCs containing PCLLA50 90/10 also exhibited a better fibroblast distribution, enhanced myofibroblastic differentiation, and a three-fold increase in cell proliferation (when the electrospun type was used) compared to collagen controls. These findings were instrumental in selecting a potential HC that might be used for future experiments in vivo.

Synthesis and characteristics properties of lignified PVA copolymer with enhanced UV-blocking performance and water solubility

The increasing environmental concerns have heightened the pursuit of sustainable materials, with a particular emphasis on biodegradable polymers. Polyvinyl alcohol (PVA), a recognized biodegradable synthetic polymer, faces challenges such as cost, slow biodegradation, and limited UV resistance. This study explores lignin, an abundant and eco-friendly biopolymer, as a cost-effective additive to enhance PVA properties via the copolymerization technique. The Mannich reaction was utilized to effectively alkylate lignin with allylthiourea, leading to the synthesis of a lignin-based macromonomer (LATU). Subsequently, the LATU macromonomer was copolymerized with vinyl acetate, producing Poly(VAc-Co-LATU) copolymer in a reaction conducted at 70 °C for 6 h. Finally, the copolymers were hydrolyzed (saponification) with potassium hydroxide to obtain Poly(VA-Co-LATU) copolymers. Extensive investigations, including FTIR, XPS, XRD, and 1H NMR, effectively validated the synthesis of the copolymers. The high monomer conversion rate above 89 % emphasizes the effectiveness of the synthesis method. The addition of LATU has a direct impact on the crystalline structure of the copolymer. X-ray diffraction patterns indicate a reduction in crystallinity, which in turn affects the other properties of the synthesized copolymers. Consequently, the lignified copolymer, Poly(VA-co-LATU), exhibited slight decrease in molecular weight (Mw), improved UV-blocking effectiveness, and greater solubility in water as comparison to PVA. This study demonstrates the feasibility of using lignin as a monomer to create novel bio-based polymeric materials that exhibit the necessary properties for certain applications.

Dynamic Surface Properties of Copolymers of Styrene and Hydrophobized 4-Vinylbenzyl Chloride at an Air–Water Interface

Dynamic Surface Properties of Copolymers of Styrene and Hydrophobized 4-Vinylbenzyl Chloride at an Air–Water Interface

Fully biobased poly(butylene furanoate) copolyesters from renewable 2,3-butanediol: Much more than just strengthening and toughening

Making full use of renewable biomass resources to develop biobased polyester plastics with balanced performance is an important part of achieving a low-carbon circular economy. As a representative variety of biobased furan polyesters, the insufficient mechanical properties limit the application of poly(butylene furanoate) (PBF) toward sustainable film materials. This study proposes a trade-off strategy by inserting the rigid biobased 2,3-butanediol (2,3-BDO) unit into the PBF molecular chain. The results show that inserting a small amount of 2,3-BDO can simultaneously realize the strengthening and toughening of PBF. When the content of 2,3-BDO reaches only 4 mol%, the copolymer possesses the tensile strength of 67.0 MPa with the elongation at break of 556.2 %. More appealingly, the crystallizability and barrier properties of copolymers can still be maintained to a certain extent. In general, by inserting a small amount of rigid 2,3-BDO unit, the fully biobased copolyesters can achieve a good balance in terms of crystallization, mechanical, and barrier properties, guaranteeing them to meet the requirements where high strength and toughness are needed.

Surface Thermodynamic Properties of Styrene–Divinylbenzene Copolymer Modified by Supramolecular Structure of Melamine Using Inverse Gas Chromatography

The surface thermodynamic properties of polymers and copolymers modified by supramolecular structures are used in several industrial processes, such as selective adsorption, paints, coatings, colloids, and adhesion applications. Background: Inverse gas chromatography at infinite dilution was proved to be the best technique to determine the surface properties of solid surfaces by studying the adsorption of some model polar and non-polar organic molecules adsorbed on solid surfaces at different temperatures. Methods: The retention volume of adsorbed solvents is a valuable parameter that was used to obtain the London dispersive and polar free energies and the London dispersive surface energy of styrene–divinylbenzene copolymer modified by supramolecular structure of melamine using both the Hamieh thermal model and our new methodology consisting of the separation of the two polar molecules and the dispersive free energy of their interaction. This led to the determination of the polar acid and base surface energy, and the Lewis acid–base constants of the various solid materials. Results: Following our new methodology, all surface energetic properties of styrene–divinylbenzene copolymer modified by melamine at different percentages were determined as a function of temperature. Conclusions: It was observed that the styrene–divinylbenzene copolymer exhibited the highest London dispersive surface energy, which decreased when the melamine percentage increased. All materials presented higher Lewis basicity and this Lewis basicity increased with the percentage of melamine.

Modeling and analysis of polypropylene copolymer properties and pressure stability for integrated tubular loop reactor and MZCR

In the context of the emerging multizone circulating reactor (MZCR) operating with gas–solid phases, maintaining pressure balance is crucial for both reactor stability and achieving intended product quality. In this study, the method of moments, reactor model and pressure balance model are coupled to model and analyze an entire process flow for propylene (co)polymerization, which integrates a pre-polymerization tubular loop reactor (TLR) with a main polymerization MZCR. The modeling results unveil the relevance of pre-polymerization in the entire MZC process flow. Additionally, the influence of typical operating parameters on both the pressure stability and copolymer properties is investigated. To further visually identify the pressure-stable boundary of the MZCR, a method based on analyzing the pressure balance loop is proposed. The current study has illustrated the variation trends of pressure drops and product properties under typical operating conditions, identifying an operational range essential for reactor safety.

Synthesis and properties of AM/AMPS/MMA and cationic monomer copolymer flooding agent

Abstract A novel hydrophobic association copolymer (PAMA) was synthesized by incorporating acrylamide (AM), 2-acrylamide-2-methylpropanesulfonic acid (AMPS), cationic monomer (MEDDA), and methyl methacrylate (MMA). The properties of MMA copolymers with varying contents were analyzed using infrared spectroscopy, nuclear magnetic resonance spectroscopy, and scanning electron microscopy. Optimal overall performance of the solution was achieved when the MMA content reached 1.4 % w/w. Compared to pure PAAM (without MMA), the PAMA-1.4 % polymer exhibited superior viscoelasticity, temperature resistance, and shear resistance. This enhancement in PAMA performance can be attributed to the significant inhibition of intermolecular water film formation within the polymer matrix by MMA, effectively improving and regulating solution solubility while strengthening molecular chain interactions and enhancing the structural network strength of PAMA polymers. Additionally, the inclusion of MMA transformed rock surfaces from non-wetting to wetting conditions, thereby greatly improving oil displacement efficiency. In displacement experiments, PAMA-1.4 % performed better in terms of enhanced oil recovery, the recovery rate of 0.1 % w/w PAMA-2.4 % solution is only 7.78 %, while the recovery rate of 0.1 % w/w PAMA-1.4 % solution is 13.06 %.

Synthesis and properties of chiral liquid crystal copolymers with tunable circularly polarized luminescence

Chiral liquid crystals have received widespread attention due to their unique advantages in improving circularly polarized luminescence (CPL) properties. However, how to achieve the emission and modulation of CPL for chiral liquid crystals within intrinsic polymer-based materials through a simple strategy remains a challenge. This article proposes a simple and feasible method to synthesize CPL chiral liquid crystals and manipulate their properties by copolymerizing chiral liquid crystal monomer with luminescent monomer. A series of intrinsic chiral luminescent liquid crystal copolymers C*(x)-Py(y) with tunable CPL performance were synthesized by copolymerizing chiral liquid crystal monomer MA6C* with pyrene-based luminescent monomer MC6Py in varying ratios. The effective control of the chiral liquid crystal phase structure and CPL performance of the copolymers C*(x)-Py(y) can be achieved by altering the composition of copolymers. In the copolymers, the CPL signal is generated due to the helix induction of pyrene chromophores by the chiral liquid crystals, and the CPL signal can be inverted and amplified by the unique selective reflection properties of chiral liquid crystals. For copolymer C*(0.75)-Py(0.25), the luminescence dissymmetry factor value and solid-state fluorescence quantum yield can reach −0.052 and 43.12%, respectively.

Molecular Dynamics Study of Adhesion-Related Structural Properties for PVDF-HFP Polymer Binders

The current lithium-ion battery (LIB) market is expanding rapidly. Binders are essential to maintaining the high capacity and longevity of batteries. These binders can be classified into organic binders used for cathodes and aqueous binders used for anodes. Among them, Poly(vinylidene fluoride) (PVDF) binder is a representative organic binder that offers excellent electrochemical stability. To solve low adhesive force and weak mechanical strength of conventional PVDF binders, hexafluoropropylene (HFP) is added to improve these properties. However, the present poly(vinylidene fluoride-hexafluoropropylene) (PVDF-HFP) binders still show lower adhesive force than other polymeric binders, and therefore further research works are necessary.In this study, we employ classical molecular dynamics (MD) simulations to investigate the structural properties of the PVDF-HFP copolymers. To create realistic disordered PVDF-HFP polymers, we develop a computational scheme that can randomly arrange the angles and sequences of the constituent polymer chains. By varying the ratio of randomly arranged PVDF-HFP copolymers to 0/100, 5/95, 10/90, 15/85, and 20/80, we build a solution model that mimics the HFP concentration of PVDF-HFP (0–20%, Sigma Aldrich) used in the actual experiments. N-methyl-2-pyrrolidone (NMP) used as solvents. To create a large-scale model, we utilize the Large-scale Atomic/Molecular Massively Parallel Simulator (LAMMPS) and set parameters by using OPLS force field. This allows us to build a simulation model containing approximately 40,000 atoms consisting of 10 PVDF-HFP polymers and 1500 NMP monomers.After creating the simulation model, approximately eight steps of molecular dynamics simulation are performed by referring to the process of making the actual polymer film. In this process, NMP molecules are evaporated to produce a polymer film consisting only of PVDF-HFP polymers. Then we perform the adhesion analysis by applying forces to five polymer film models with different composition ratios in various conditions. Throughout these processes, we find the characteristic changes depending on the composition ratio. Finally, we will present the possible routes that can lead to the enhanced adhesive properties of PVDF-HFP, which is a key requirement to the development of high performance binders.

Role of Annealing with Electric Field Toward Improvement of Ferroelectric and Electroactive Properties of PVDF Copolymer and Terpolymer Thin Films.

The present study elucidates the role of annealing with electric field on lamellar crystalline structure and molecular orientation of polymer chains in ferroelectric copolymer (P(VDF-TrFE)) and ferroelectric terpolymer (P(VDF-TrFE-CFE)) spin-coated thin films. The ferroelectric polymer thin films annealed under an electric field support the growth of nanostructure with an "edge-on" lamellar crystalline structure having in-plane molecular chain orientation. The poled P(VDF-TrFE) thin films have higher remnant polarization (Pr) ≈6.2µCcm-2 and saturation polarization (Ps) ≈8.2µCcm-2 at an applied electric field of 250 MV/m compared to unpoled thin films having Pr ≈4.7 and Ps ≈6.2µCcm-2. Also, poled P(VDF-TrFE) thin films show lower coercive field (Ec) ≈94 MV/m compared to an unpoled thin film having Ec ≈105 MV/m. Similarly, poled PVDF-TrFE-CFE thin film shows better ferroelectric properties having Pr ≈0.4 and Ps ≈5.7µCcm-2 at an applied electric field of 200 MVm-1 compared to unpoled thin films having Pr ≈0.4 and Ps ≈4.1µCcm-2. The storage energy efficiency of unpoled and poled P(VDF-TrFE-CFE) thin films is measured to be ≈75% and 80%. Annealing of ferroelectric P(VDF-TrFE) polymer thin films under an electric field demonstrates improved ferroelectric and electroactive properties.

Synthesis and Properties of Mesogen-Jacketed Liquid Crystal Copolymers with Long-Lived Circularly Polarized Room-Temperature Phosphorescence

Synthesis and Properties of Mesogen-Jacketed Liquid Crystal Copolymers with Long-Lived Circularly Polarized Room-Temperature Phosphorescence

Potential of caffeic acid as an effective natural antioxidant for polypropylene-polyethylene copolymers: A DFT and experimental study

Caffeic acid (CAF) i is a polyphenolic compound commonly found in plants, valued for its ability to act as an antioxidant. This study focused on investigating the impact of a natural antioxidant, specifically caffeic acid (CAF), compared to two synthetic antioxidants, butylated hydroxyanisole (BHA) and butylated hydroxytoluene (BHT), on the thermal stability of propylene/ethylene copolymer (C-PP/PE), Aiming to establish a theoretical framework for the advancement of novel polymeric antioxidant compounds. Theoretical calculations were conducted to determine each compound's thermodynamic properties and antioxidant activity. The phenolic hydroxyl bond dissociation enthalpy (BDE) values revealed that BHA had the lowest value (325.6 kJ mol−1), trailed by CAF (328.2 kJ mol−1) and BHT (341.3 kJ mol−1), indicating a higher electron-donating capacity of BHA. Transition energy (TS) calculations indicated that BHA had the lowest TS energy (49.29 kJ mol−1), succeeded by CAF (57.61 kJ mol−1) and then BHT (75.57 kJ mol−1), suggesting greater efficiency in radical scavenging. Additionally, the obtained rate constants showed that CAF had the highest hydrogen abstraction rate (k = 1.05 × 10⁵ M⁻1 s⁻1), followed by BHA (k = 1.17 × 10⁴ M⁻1 s⁻1), and then BHT (k = 4.2 × 10³ M⁻1 s⁻1). These results support the effectiveness of CAF as a potentially more active antioxidant. In the experimental part of this study, it was observed that C-PP/PE with BHA showed a lower melt flow index (MFI) (8.51), indicating more excellent thermal stability. On the other hand, samples containing natural caffeic acid extracts exhibited a gradual decrease in MFI with increasing CAF concentration (MFI of 9.4, 8.82, 7.59, 6.44, and 5.98 for concentrations of 0.025, 0.05, 0.075, 0.1, and 0.125 ppm, respectively), suggesting a progressive improvement in the thermal stability of C-PP/PE with increasing natural antioxidant. In TGA analyses, decomposition was observed around 340 °C in samples without additives and those containing 0.1 ppm of BHA. In contrast, samples with different concentrations of CAF showed delayed degradation, observed in the temperature range of 380–400 °C. This delay in degradation indicates that CAF imparts more excellent thermal stability to C-PP/PE copolymer, as it reaches temperatures above 400 °C before starting its decomposition. These findings support the feasibility of using natural antioxidants such as CAF to improve the thermal properties of copolymers.

Fabrication of bacterial derived natural polysaccharide-based copolymer network hydrogels for use in drug delivery applications

Researchers are currently exploring polysaccharide gums extensively to develop materials for biomedical applications. Herein, the bacterial-derived natural polysaccharide xanthan gum (XG) was utilized to develop copolymer network hydrogels to use in drug delivery (DD) applications for sustainable development. These copolymers were synthesized by grafting METAC onto XG and characterized by FE-SEM, EDX, AFM, FTIR, XRD, 13C NMR, DSC, and TGA-DTG techniques. These hydrogels were encapsulated with the anticancer drug dacarbazine. The diffusion of dacarbazine from the hydrogels exhibited a non-Fickian diffusion mechanism, and the release profile was most appropriately explained by a zero-order kinetic model. In addition, network hydrogels illustrated their superabsorbent nature by absorbing about 15 g of fluid per gram of polymer sample. The materials revealed antioxidant activity in the DPPH scavenging method. Findings of the physicochemical, drug delivery, antioxidant and antibacterial properties of copolymers revealed their suitability for use in DD applications.