Polymer International最新文献

Plant oil-based acrylic monomers from hydrogenated sunflower (HFM), palm (PMM) and castor (CSM) oils were polymerized to investigate the effect of chemical composition on polymer phase transitions at temperatures relevant to physiological range. While HFM and PMM possess a highly differing content of saturated palmitic and stearic acids combined with unsaturated fatty acids, CSM contains primarily fragments based on monounsaturated ricinoleic hydroxy acid (up to 90%). Differential scanning calorimetry (DSC) measurements indicate that polymers from PMM and HFM are both semicrystalline (with T_m = −6 and −13 °C, respectively), while poly(CSM) appears to be amorphous (T_g = −49 °C). Considering the similarity in polymers' molar mass (M_n = 16 000–20 000 g mol⁻¹), the observed thermal transitions can be explained by the formation of ordered morphological domains due to the presence of saturated palmitic and stearic acid fractions in poly(PMM) and poly(HFM). For copolymers of CSM, PMM and HFM (80 wt% of monomer feed) with styrene, DSC data show two transitions corresponding to the mobility of long alkyl fatty acid side fragments and the macromolecular backbone. For copolymers of PMM and HFM, comparable values (−52.8 and −55.5 °C, respectively) were obtained, while the second transition for poly(CSM-co-styrene) appears at 35 °C. We attribute this higher value to the presence of hydroxyl groups in ricinoleic acid fragments of CSM serving as additional chain transfer sites and the formation of macromolecular fractions enriched with polystyrene fragments. We expect that the temperature transitions obtained can be relevant to the future use of these polymers for biomedical applications, including the synthesis of polymer brushes. © 2024 Society of Chemical Industry.

Thermoplastics based on polyolefins, including polypropylene, high-density polyethylene and low-density polyethylene, are extensively utilized across various packaging sectors. The selection of these materials for specific applications is influenced by multiple factors, such as the polymer's absorption characteristics and the impact on its mechanical properties when in contact with the packaged product. This study presents an experimental methodology designed to simulate the effects of absorption on the macroscopic and microscopic properties of high-density polyethylene bottles in contact with amyl acetate. Macroscopic degradation was evaluated by modeling mechanical damage using unified theory and the energy method. Analytical techniques such as gravimetric analysis, scanning electron microscopy and Fourier transform infrared spectrometry were employed. The findings of this research provide valuable insights for suppliers and industries to experimentally determine the usability and safety intervals of plastic packaging through comprehensive macroscopic and microscopic analyses within relatively short timescales. © 2024 Society of Chemical Industry.

Maleimides are remarkably versatile functional groups, capable of participating in homo- and copolymerizations, Diels–Alder and (photo)cycloadditions, Michael additions, and other reactions. Their reactivity has afforded materials ranging from polyimides with high upper service temperatures to hydrogels for regenerative medicine applications. Moreover, maleimides have proven to be an enabling chemistry for pharmaceutical development and bioconjugation via straightforward modification of cysteine residues. To exert spatiotemporal control over reactions with maleimides, multiple approaches have been developed to photocage nucleophiles, dienes, and dipoles. Additionally, further substitution of the maleimide alkene (e.g. monohalo-, dihalo-, thio-, amino- and methyl-maleimides, among other substituents) confers tunable reactivity and dynamicity, as well as responsive mechanical and optical properties. In this mini-review, we highlight the diverse functionality of maleimides, underscoring their notable impact in polymer science. This moiety and related heterocycles will play an important role in future innovations in chemistry, biomedical, and materials research. © 2024 The Author(s). Polymer International published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

In this study, a viable route to the development of a high-performance polyoxymethylene (POM)-based nanocomposite is proposed to overcome tribomechanical-related issues in high-precision sliding parts. Prior to melt-blending, graphene nanoplatelet (GNP) filler was processed via a series of liquid-phase exfoliation and surface modification with 3-aminopropyltriethoxysilane. Results indicate that GNP is successfully exfoliated with minimum defect ratio and improves interfacial bonding within the matrix. Uniform dispersion and stable load-transfer capability of POM/GNP with 0.5 wt% loading significantly enhanced flexural, tensile and impact strength by overall 26.4%, in contrast to unfilled POM. Dry friction tests against a steel ball also showed the lowest reduction in friction coefficient and wear rate by 22% and 40.6%, respectively, at the same amount of GNP loading due to the large specific surface coverage and lubricious transfer film chelation onto the steel counterface. Furthermore, dissipated energy accumulation by friction work was calculated in the sliding interfaces based on friction force–displacement hysteresis loop where the POM/GNP 0.5 wt% wear surface consumed ca 21.7% less energy in a dry frictional shearing process compared to neat POM. However, lack or excess loading of processed GNP exhibited insufficient or poor matrix–filler adhesion and led to deterioration of the composite properties due to particle agglomeration which can cause stress concentration and serve as a failure site. The adoption of the proposed methodology would demonstrate excellent material characteristics in thin-walled precision parts where both mechanical and tribological performances are the primary concern. © 2024 Society of Chemical Industry.

Additive manufacturing is a technology that promises to disrupt the conventional manufacturing industry due to its ability to create complex structures with improved macroscopic control not available with existing techniques like molding or milling. In addition to superior macroscopic structural control, photoprinting methods such as digital light projection can enable molecular-scale control over the fabrication process by taking advantage of the self-sorting or assembly properties of the monomers themselves. Polymerization-induced phase separation (PIPS) allows for the remarkable introduction of microscopic control into additive manufacturing, using polymer-rich and polymer-poor regions that rely on incompatibilities to phase separate during polymerization creating new complex materials not achieved by traditional methods. With the incorporation of porogens or filler materials, microporosity and/or surface functionalization can be introduced in a facile one-step printing process. This expands the potential applications of 3D printed materials, to include micro- and macroscale structural control. Using PIPS as a design strategy, polymeric materials with previously unprecedented capabilities can be produced with ease enabling 3D printing to grow into its full potential as a manufacturing tool. © 2024 Society of Chemical Industry.

The utilization of natural polymers in producing electrospun nanofibers has received significant attention due to their biocompatibility, sustainability and diverse range of applications. This research focuses on synthesizing electrospun nanofibers derived from taro starch isolated from tubers. The investigation utilized SEM to examine the structure and size of the electrospun nanofibers. Formic acid and dimethyl sulfoxide solvents were tested to determine the most efficient solvent system for synthesizing taro starch nanofibers. The results demonstrated that the taro starch nanofibers can be effectively synthesized when using formic acid as the primary solvent. The study also investigated the impact of altering the volumetric ratio of formic acid to water on nanofiber morphology and size, finding that a lower formic acid fraction produced smooth fibers while a higher fraction resulted in fused fibers. The electrospinnability was further evaluated by comparing the effects of different isolation agents—distilled water and sodium metabisulfite—during the isolation process. The isolation agent significantly affected the fiber diameter, with notable differences observed in the smoothness of taro starch nanofibers at starch solution concentrations of 13, 15 and 17 wt%. Overall, the results of the study showed that the formation of taro starch fibers was influenced by the type of solvent, the volume fraction of the solvent to water, and the starch isolation agent. Successful fabrication of nanofibers from taro starch and its optimization parameters can contribute to the development of environmentally friendly nanofiber materials and offer a variety of applications in biomedicine, food and environmental engineering, such as tissue engineering, wound dressing, drug delivery, functional food delivery and food packaging. © 2024 Society of Chemical Industry.

The distribution and conformational state of compatibilizer polymers at the interface between two phases are challenging to obtain in detail through experimental research due to spatial scale limitations. This paper employs dissipative particle dynamics simulation to statistically analyze the size variations of compatibilizer copolymers at the interface of a binary blend system. The study examines the impact of factors such as the chain length of blended homopolymers, the topological structure of the compatibilizer and component interactions on the size distribution of compatibilizer copolymers at the interface. The scaling exponent between the size of the compatibilizer copolymers and their chain length is determined and compared with theoretical values under melt conditions. The reasons for the variation in the scaling exponent are analyzed, providing theoretical supplementation for the distribution, size changes and compatibilization effects of compatibilizers during the blend modification process. The results reveal discrepancies between the scaling exponent of chain size and chain length at the interface and theoretical values, analyze the significant impact of compatibilizer copolymer topological structure on the scaling exponent and present the influence of the component interaction parameter α on the scaling exponent's variation pattern. The simulation outcomes offer theoretical support for the design and selection of compatibilizers in a blend system. © 2024 Society of Chemical Industry.

Polymers play a significant role in the modern world and have broad applications, particularly in medicine and pharmacology. However, polymer debris represents a significant environmental threat. Therefore, new materials with exceptional performance and environmental safety are needed. The circular economy has led to the development of ‘green polymers’ with enhanced renewability, biodegradability and compostability and properties similar to those of conventional polymers but with a significantly reduced carbon footprint. Green polymers have been extensively utilized in formulating diverse materials for medical purposes. Using green polymers for medical and pharmaceutical applications may improve outcomes for non-communicable diseases by providing safer and more effective drug delivery systems, reducing side effects with improved biocompatibility and enhancing targeted disease treatments. Green polymer-based materials can be engineered in various applications, making them particularly beneficial in managing chronic conditions like cancer, diabetes or cardiovascular diseases, where reliable and long-term treatments are vital. Therefore, this review highlights the importance of a comprehensive understanding of green polymers as novel material sources for improving the treatment and control of non-communicable diseases. © 2024 Society of Chemical Industry.

The present work generated hybrid composite sandwiches by incorporating 65% epoxy resin and 35% reinforcements derived from pineapple and glass fibres. The specimens were subjected to mechanical characterization by tensile, flexural and impact examinations. Among the untreated samples, the specimens containing untreated pineapple fibres (PF) with a composition of 17% PF, 18% glass fibres (three layers) and 65% epoxy by weight (17PF/TLGF) showed the most superior mechanical characteristics. Nevertheless, specimens containing fibres treated with NaOH exhibited exceptional characteristics, attaining a tensile strength of 88.121 MPa, a flexural strength of 94.213 MPa and an impact energy of 4.1 J. These data indicate a 20% enhancement in both tensile and flexural strength as well as a 63% improvement in impact strength compared to specimens containing 35% PF and lacking glass fibres (35PF/0GF). In comparison to 17PF/TLGF, the specimens treated with NaOH exhibited a 4.34% gain in tensile strength, a 4.24% increase in flexural strength and a 9% increase in impact strength. Experimental TGA was performed on the chemically treated fibre composite specimens, specifically identified as 35PF/0GF and 17PF/TLGF. Approximately 260 °C marked the beginning of decomposition for the 35PF/0GF sample, but the 17PF/TLGF sample decomposed at roughly 310°C. In addition, the fragmented surface of the 17PF/TLGF sample was analysed using SEM. © 2024 Society of Chemical Industry.

This research investigates the impact of sawdust fillers on Cucumis sativus fiber-reinforced polymer composites through a conventional hand layup process. The objective is to develop a novel material suitable for static applications that is both lightweight and environmentally sustainable. A range of analytical techniques including X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, mechanical testing, thermogravimetric analysis (TGA), scanning electron microscopy (SEM) and energy-dispersive X-ray (EDX) analysis were employed to thoroughly characterize the resulting composite material. By integrating Cucumis sativus fibers and sawdust fillers into a polymer matrix, the study demonstrates the potential to create materials with improved mechanical properties due to addition of sawdust filler, including tensile strength (27.61 MPa), flexural strength (32.84 MPa), impact resistance (14.7 J cm⁻²) and hardness (42). These enhancements, averaging at 16.2%, are attributed to the addition of sawdust filler, which opens new avenues for environmentally conscious engineering solutions. XRD analysis reveals the composite's crystalline structure, indicating a crystallinity index of 64.5% and the orientation of crystalline planes. FTIR spectroscopy identifies chemical bonding and CO and CO functional groups present in the material with major peaks at 2123 and 2438 cm⁻¹. TGA assesses the composite's thermal stability and decomposition behavior up to 380 °C. Additionally, SEM imaging elucidates the microstructural features and distribution of Cucumis sativus fibers and sawdust fillers within the epoxy matrix, while EDX analysis provides quantitative data on elemental composition. © 2024 Society of Chemical Industry.