Polymer International最新文献

Microbial polyhydroxyalkanoates (PHAs) are biocompatible and biodegradable polyesters synthesized from biomass resources by various microbes in appropriate growth conditions as intracellular energy storage. PHAs have great biocompatibility, low immunological response, bioresorption, non-toxic degradation products and possibly resilient cell adhesion properties. Their mechanical characteristics can be modified to fit numerous tissues ranging from very soft (skin) to hard (bone). Multiple approaches have been used to create well-defined architectures with the best characteristics for processing as medical devices and biomedical application tools. The implementation of PHAs into medical devices as new functional materials with advanced 3D printing techniques has been described. Additionally, new challenges in improving PHA-based bioinks for creating scaffolds with enhanced biodegradation control suitable for tissue regeneration are also elucidated in this review. © 2024 Society of Chemical Industry.

Starch phosphate carbamate was synthesized via a one-pot method using phosphoric acid, urea and starch, and it was added into polyurethane (PU) to replace some polyol. The fire retardancy and thermal stability of the resulting PU system were evaluated by the results of vertical burning test (UL-94), limiting oxygen index (LOI), cone calorimeter (CONE) test and thermogravimetric analysis. Raman spectroscopy and X-ray photoelectron spectroscopy were used to analyze the char layer after the CONE test, and the thermogravimetric–infrared test was used to analyze the gas products at the maximum rate of thermal decomposition. The introduction of 13.7 wt% starch phosphate carbamate (PU-15) in PU enables the system to pass the V-0 rating, with LOI reaching 22.8%. The peak heat release rate of PU-15 decreased by 36.54% compared to PU, and the total heat release of PU-15 was only 27.87 MJ m⁻². Starch phosphate carbamate reduces the generation of combustible small molecules during the combustion of the system, producing a more protective char layer. Raman results indicate that starch phosphate carbamate can increase the stability of the char layer. Integrating the results from various tests, the combustion mechanism of PU with starch phosphate carbamate was explored. Starch phosphate carbamate provides a new approach for preparing high-performance PU. © 2024 Society of Chemical Industry.

This study investigates the synthesis, nucleation and modification of biodegradable poly(sodium sulfonated butylene fumarate-co-acrylic acid)/hydroxyapatite nanocomposite scaffolds for bone tissue engineering, with a focus on the effects of incorporating hydrophilic sulfonate and carboxylic acid groups. Poly(butylene fumarate) was sulfonated at varying degrees and used to form nanocomposites through in situ nucleation of nanohydroxyapatite (nHA) in a simulated body fluid solution. Critical parameters such as water absorption, swelling behavior, mechanical properties, nanoparticle dispersion and biocompatibility were evaluated. Water uptake ratios ranged from 2.72 to 6.88 g g⁻¹, while compressive modulus values increased up to 25.9 times compared with the corresponding homopolymers, demonstrating improved mechanical stability. Despite the formation of over 80% nanoparticles, well-distributed nHA, with sizes averaging 39 ± 13 nm, was achieved through the incorporation of sulfonated groups, preventing nanoparticle agglomeration within the scaffold matrix. Additionally, the scaffolds supported human dermal fibroblast adhesion and proliferation, with cell viability remaining high throughout the culture period. These results suggest that the developed nanocomposite scaffolds offer enhanced biocompatibility, mechanical strength and osteogenic potential, making them promising candidates for bone tissue regeneration applications. © 2024 Society of Chemical Industry.

A novel approach is developed for the preparation of a membrane electrode assembly with low methanol crossover, designed for application in direct methanol fuel cells. This method involves a two-step process starting with the modification of a Nafion membrane through chemical oxidative polymerization of pyrrole, using FeCl₃ as an oxidant. Subsequently, galvanostatic electrodeposition of several metals (copper, nickel and silver) was performed on the previously prepared composite membrane (polypyrrole–Nafion). Scanning electron microscopy was conducted to examine the growth evolution, morphology and distribution of the deposited polypyrrole and metals. Additionally, X-ray photoelectron analysis enabled for the identification of elemental composition and chemical states within the coating to confirm the growth evolution, morphology and oxide phases present in the coatings, as well as their structural characteristics. © 2024 Society of Chemical Industry.

Wound management is a complex clinical challenge that needs advanced materials and techniques for satisfactory results. Electrospun nanofiber mats have emerged as an innovative alternative for wound healing purposes due to their porous architecture, greater surface area, ease of water absorption, mimicry of the extracellular matrix of natural tissues and tunable mechanical properties. This paper sheds light on recent advances in the fabrication techniques, properties, structural features and application of electrospun polymeric nanofiber mats for wound healing purposes emphasizing the importance of polymer selection and processing parameters in tailoring their physicochemical properties. Furthermore, the review explores the underlying principles of the wound healing process and various approaches to incorporating bioactive agents into nanofiber mats to enhance their biological performance and wound healing potential. The possibility of embedding stimuli-responsive sensors into the nanofiber mats to develop smart mats is also briefly explored. © 2024 Society of Chemical Industry.

Transport phenomena of chemical species in polymers underpin many applications. This mini-review discusses several key transport scenarios in polymer gels, melts and crosslinked polymer networks. Transport mechanisms of a wide variety of penetrant and polymer chemistries are discussed via activated hopping theory and cover across the rubbery, intermediate/deeply supercooled and glassy states of polymers. Moreover, we also discuss the ionic conductivity in polymer electrolytes, emphasizing the relationship between ion diffusion and the segmental relaxation of polymers and highlighting current challenges in the community. Finally, potential research directions are suggested concerning how external fields, such as mechanical force fields, active matter and self-propelling particles, affect the particle transport in polymers. This mini-review offers a general overview of motivations for studying penetrant transports in polymers and diverse mechanisms involved. © 2024 Society of Chemical Industry.

In recent decades, lithium-ion batteries have become the leading energy storage solution due to their rechargeability, long lifespan, high energy density and lightweight design, although the conventional liquid electrolytes used raise performance and safety concerns, particularly regarding volatility and flammability at high temperatures. This study explores the incorporation of nanocellulose (NC) derived from cassava peels into polymer electrolyte membranes based on poly(ethylene oxide) (PEO). NC serves as a reinforcing agent, enhancing the mechanical properties of the membranes, such as tensile strength, while its natural abundance and biocompatibility offer a sustainable alternative for electrolyte materials. The membranes were prepared via the solution casting method utilising water as the solvent and subsequently characterised using Fourier transform infrared spectroscopy, XRD, a tensile tester, SEM and TGA/differential thermal analysis/DSC. Incorporating NC into the PEO matrix resulted in enhanced tensile strength and reduced strain at break, while negligibly impacting the ionic conductivity of the membrane. The most effective membrane composition was achieved at a PEO to NC ratio of 80:20, with the optimum ionic conductivity of the polymer electrolyte being 1.54 × 10⁻⁴ S cm⁻¹, a tensile strength of 34.87 MPa and an elongation at break of 65.6%. This research sheds light on the potential of utilising NC from cassava peels to improve the performance and safety of polymer electrolyte membranes for lithium-ion batteries. © 2024 Society of Chemical Industry.

In the present study, the macromolecular chain composition of copolymers prepared by the reactive blending of poly(ethylene terephthalate) (PET) and bisphenol A polycarbonate (PC) in the presence of Ti(OBu)₄ catalyst was tested using ¹H and ¹³C NMR spectroscopy. The NMR spectra were meticulously analyzed across all regions, revealing unexpected results that provide new insights into the transreaction mechanism occurring between these two polymers in the melt phase. It was found that only two primary reactions occurred: the formation of a bisphenol A terephthalate bond accompanied by the release of ethylene carbonate and the formation of an aliphatic–aromatic ether bond with the release of CO₂. The release of ethylene carbonate during the PET-PC blending led to a loss of ethylene glycol (EG). The kinetics of EG loss and ether bond formation were examined. A new transreaction mechanism for PET-PC reactive blending is proposed. © 2024 Society of Chemical Industry.