Polymer Science, Series A最新文献

One of the main treatment methods for diabetes is the subcutaneous injection of insulin. However, frequent subcutaneous injections can lead to adverse reactions, such as swelling and inflammation at the injection site, resulting in poor patient compliance. In contrast, non-invasive insulin delivery methods, particularly oral administration, offer advantages in terms of improved patient compliance, convenience, and cost-effectiveness. Nevertheless, the multiple physiological barriers in the gastrointestinal tract pose significant challenges to the oral delivery of protein or peptide drugs. Biodegradable polymer materials are now widely used in the research of oral insulin delivery due to their excellent properties, including good biocompatibility, biodegradability, and low toxicity. These materials are capable of protecting insulin from degradation in the harsh environments of the stomach and intestinal lumen, thus enhancing the oral bioavailability of insulin. This paper has described the various physiological barriers of oral insulin delivery and summarized the types and properties of biodegradable polymeric materials that have been used for oral insulin delivery in recent years.

A polymer composite material for medical applications based on acrylic hydrogels and detonation nanodiamonds containing the medicinal substance metronidazole has been synthesized. The kinetics of gel swelling in media of different ionic strengths and pH values and the kinetics of metronidazole release from it have been studied. It has been shown that detonation nanodiamonds affect the completeness of metronidazole release. Mathematical models that best describe the process of metronidazole desorption and swelling kinetics have been proposed. The mechanical properties of the hydrogels and the frequency dependences of their dynamic moduli have been studied using oscillation rheometry methods. The effect of detonation nanodiamonds and metronidazole on the dynamic moduli, the mechanical loss tangent, and the parameters of the polymer matrix network has been shown.

ABA–type amphiphilic poly(N-isopropylacrylamide)-block-poly(L-lactide)-block-poly(N-isopropylacrylamide) (PNIPAM-b-PLLA-b-PNIPAM) was synthesized via combination of ring opening polymerization (ROP) and atom transfer radical polymerization (ATRP) using the novel bifunctional PLLA–based ATRP macroinitiator bearing 1,2-bis[(3-oxapropyl)oxa]benzene core. For this purpose, at first bifunctional diol initiator, o-bis[(3-hydroxypropyl)oxy]benzene (1), was synthesized by the reaction of catechol and 3-chloro-1-propanol in the presence of sodium hydroxide (NaOH) in ethanol. Secondly, PLLA-diol (HO-PLLA-OH) was prepared by Sn(Oct)₂ -catalyzed (ROP) of (L-LA) at 120°C using (1) as initiator in toluene. Thirdly, dibromoester end-functionalized PLLA-based ATRP macroinitiator (Br-PLLA-Br) was synthesized by esterification of hydroxyl end groups of PLLA-diol. Finally ABA-type block copolymer, (PNIPAM-b-PLLA-b-PNIPAM), was synthesized by (ATRP) of NIPAM as monomer using PLLA-based ATRP macroinitiator in presence of copper(I) chloride/tris[2-(dimethylamino)ethyl]amine (CuCl/Me₆TREN) as catalyst system in DMF/water at 25°C. Characterization of the molecular structures for synthesized novel macroinitiator and the block copolymer were made by spectroscopic (FTIR and ¹H NMR) and chromatographic (GPC) methods. In the application phase of this study, the effectiveness of polymers was examined on cancer cells. Cytotoxicity and metastatic effects were evaluated in vitro on MDA-MB-231 cell lines. As a result, novel ABA-Type PNIPAM-b-PLLA-b-PNIPAM amphiphilic block copolymer, which has been successfully developed, characterized and determined to be non-toxic, can be used as a promising drug delivery system in many areas such as tumor treatments.

For the first time, a laboratory technology has been developed for preparing poly(naphthoylene benzimidazole) incombustible nonwoven material by electrospinning from a solution of the precursor polymer, polyaminonaphthoyleneimide, through the thermal transformation stage. The influence of polymer concentration in solution and the voltage applied to the injection nozzle and collecting device on the properties of the resulting material was studied. The morphology of the new material was investigated, its mechanical, thermal, and thermomechanical characteristics were examined, and the limiting oxygen index was assessed. The optimal key operational parameters for electrospinning were determined, which constitute the essence of the laboratory technology for producing the new material.

In this study, polysiloxane microspheres were prepared by silane hydrolysis condensation method, and polysiloxane microspheres with fluorescent properties were obtained after calcination. SiO₂ nanoparticles were synthesized by the template method and composited with fluorescent polysiloxane microspheres through surface modification, and superhydrophobic composite microspheres with fluorescent properties were successfully prepared. The composites constructed multi-scale micro-nanostructures with morphology and structure similar to mosquito compound eyes. The structure and properties of the composite microspheres were investigated using characterization tools such as Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and contact angle tester. The results showed that the SiO₂ nanoparticles were successfully compounded with polysiloxane microspheres and formed a stable structure; the surface of the composite microspheres showed superhydrophobicity while retaining the fluorescent properties of the polysiloxane matrix. This fluorescent superhydrophobic composite with a bionic compound eye structure has broad application prospects in the fields of optical devices and functional coatings, etc.

Conjugated conductive organic polymers, such as polyacetylene, polythiophene, polypyrrole, and polyaniline, are among the most widely studied materials due to their unique properties and diverse applications. To explore their potential for advanced technologies, poly(meta-aminophenol) was synthesized and characterized using FTIR, XRD, UV–Vis spectroscopy, TGA, and electrical measurements. The optical properties of the doped polymer were investigated through oxidation-reduction reactions using FeCl₃ and I₂ to analyze its redox behavior. Upon doping, the energy gap of the polymers decreased, influenced by the oxidation potential of the dopants. The undoped polymer exhibited an energy gap of 3.4 eV, which reduced to 1.8 eV for the I₂-doped polymer and 2.05 eV for the FeCl₃-doped polymer. This reduction in energy gap correlated with an increase in electrical conductivity, from 8.85 × 10⁻⁴ S/m for the undoped polymer to 7.28 × 10^–3 S/m for the I₂-doped polymer and 4.22 × 10⁻³ S/m for the FeCl₃-doped polymer.

The work is devoted to the analysis of solutions of some polymers in order to optimize the concentration, which ensures the production of protective film materials with the necessary characteristics. The polysaccharides such as pectin, chitosan, the sodium salt of chitosan succinyl and the sodium salt of carboxymethylcellulose were used as the basis for the creation of materials in this work. The conducted rheological studies suggest that solutions of polysaccharides, depending on the polymer concentrations, have different degrees of structure and fluidity. Solutions with concentrations up to C_e behave like Newtonian liquids. Solutions with concentrations between C_e and C_gel are like pseudoplastic liquids. Solutions with higher concentrations behave like elastic-viscous gels. The polymer concentration in solution used in the process of forming a film coating fundamentally affects a number of physicochemical and physicomechanical characteristics of films. In order for film coatings to be characterized by maximum strength and elasticity, good sorption capacity and controlled drug yield, they must be formed from a semi-diluted solution with a concentration of С_е < С < С_gel.

Correlations between filling amount and effects in FKM of two fillers, BaSO₄ and CaF₂, were investigated to clarify differences in dispersion, binding, and reinforcement. Rheological behaviors of FKM mixtures were first explored via LAOS tests, indicating that the increase in filling content of BaSO₄ had relatively monotonous impacts on the non-linear viscoelasticity responses, while those of CaF₂ presented a complex three-stage alteration pattern. It was hypothesized that an approximate CaF₂-FKM “mesophase” was formed with filler content up to the 25–30 phr range due to the specific binding properties of CaF₂ to the FKM matrix. Next, investigations on FKM vulcanizate corroborated the conjecture provided by the LAOS test, where differences in filler aggregation morphology under SEM images and G  ' from DMA measurements were observed. Engineering tests were then conducted for FKM vulcanizates, with which the discrepancies of BaSO₄ and CaF₂ in the filling effects on FKM were further discussed. Results illustrated that BaSO₄ had poor dispersion and binding in FKM, while CaF₂ possessed more significant reinforcing effects due to its good wetting and dispersion, and the difference in performances of vulcanizate with two types of filler was most prominent in the filling range of 20–30 phr.

Polyolefin elastomer (POE) is widely used in automotive components, footwear materials, and other applications due to its excellent elasticity and thermoplastic processability. However, POE foams prepared via supercritical carbon dioxide (scCO₂) foaming often face significant shrinkage issues, severely limiting their practical applications. Enhancing the rigidity of cell walls through irreversible chemical crosslinking is the prevailing strategy for suppressing shrinkage. However, this compromises recyclability. Balancing anti-shrinkage, high foaming ratio and recyclability remains a critical challenge. In this study, we propose a novel approach to fabricate POE/FKM (fluoroelastomer) foams with high open-cell content by introducing FKM as a modifier. The results show that with 10 wt % FKM, the foams attain an open-cell content of 95.1% and a foaming ratio of 27.5 times, while the shrinkage ratio is significantly reduced from 64.6% (for pure POE foams) to 12.1%. These performance improvements are attributed to the high CO₂ affinity and heterogeneous nucleation effect of FKM, which promote the uniform cell refinement and the formation of a highly open-cell structure. This structure effectively reduces the negative pressure within the cells, thereby improving dimensional stability. This study proposes a high-performance POE/FKM foam, offering a feasible approach for developing polyolefin foams with excellent anti-shrinkage properties, recyclability, and outstanding mechanical performance.

Thermoplastic vulcanizates (TPVs) based on ethylene-vinyl acetate copolymer (EVA)/nitrile butadiene rubber (NBR)/liquid nitrile rubber (LNBR) were prepared using a dynamic vulcanization method with a copper sulfate (CuSO₄) coordination cross-linking system. The microstructures of EVA/NBR TPV and EVA/NBR/LNBR TPV were analyzed using field emission scanning electron microscopy (FE-SEM). The mechanical properties and non-isothermal crystallization kinetics of EVA/NBR/LNBR TPV, EVA/NBR TPV and pure EVA were investigated using a universal testing machine and differential scanning calorimetry (DSC), respectively. The experimental results demonstrated that the incorporation of LNBR enhanced the mechanical properties of the EVA/NBR TPV significantly. The size of the crosslinked NBR particles were refined with the incorporation of LNBR in TPV, which influenced the non-isothermal crystallization behavior of the EVA phase. Data analysis revealed that the crystallization behavior could be characterized by the Jeziorny and Mo methods effectively. The NBR phase was found to promote nucleation of the EVA matrix while simultaneously inhibiting the growth of EVA crystals. The existence of LNBR in TPV further enhanced the nucleation-promoting effect, while the influence on weakening the inhibition of crystal growth was limited.