Polymer International最新文献

Polypropylene (PP) is an unflinching element of biomaterials for human healthcare, leading to enormous possibilities for their functional development within a broad range of biocompatible and bioreceptive materials. Plasma grafting of itaconic acid was carried out on a PP surface by oxygen plasma activation. The variation of grafting parameters, such as monomer concentration, reaction temperature and reaction time, as a function of the degree of grafting was investigated. The graft distribution and surface homogeneity of the PP surfaces were evaluated using confocal microscopy, field emission scanning electron microscopy and atomic force microscopy. These surface characterizations led to information about the impact of grafts on the material surface. © 2023 Society of Industrial Chemistry.

Characterization of synthetic and natural melanin nanoparticles (MNPs) has been challenging due to the variability of properties and chemical bonding. Although eumelanin was the first to be discovered, four additional subcategories of melanin now exist including pheomelanin, neuromelanin, allomelanin and pyomelanin. Mass spectrometry (MS) methods have provided crucial insights into the bonding, structure, and mechanism regarding MNP formation, but inconsistent findings in the literature have caused further confusion in the analysis and structure of MNPs. This mini-review will focus on the types of MS experiments that have been used to analyze MNPs and what kind of information can be gained from different ionization sources, collisional activation experiments, and reaction monitoring quantitative methods when analyzing different subcategories of MNPs. Additionally, future directions regarding alternative applications of MNPs in MS experiments, mass defect analyses of complex mixtures, and a standardized nomenclature for isomeric redox states will all be addressed. © 2023 The Authors. Polymer International published by John Wiley & Sons Ltd on behalf of Society of Industrial Chemistry.

Piezoelectricity refers to the ability of certain materials to generate electric charges when subjected to mechanical stress or strain, and vice versa. This phenomenon has been widely studied in inorganic materials, such as quartz and ceramics, and has found numerous applications in sensing, actuation, and energy harvesting. There has been a growing interest in piezoelectricity for polymeric materials that are lightweight, flexible, and highly processable for a wide range of applications, including sensors for environmental and biomedical monitoring, energy conversion from mechanical vibrations, and actuation in soft robotics. However, characterizing the piezoelectric tendency of polymeric materials tends to be a complex and challenging process, as the effect is often weak and dependent upon various factors including material structure, processing conditions, and measurement setup. While many past and current review articles have covered theories and principles associated with piezoelectric polymers to some extent, detailed information on the corresponding experimental techniques used to measure their piezoelectric properties remains limited. This mini-review paper aims to consolidate and summarize various approaches, including quasi-static methods, optical interferometry, dielectric spectroscopy, and piezoelectric force microscopy, and to provide insights into the principles, advantages, limitations, and challenges associated with these techniques. © 2023 Society of Industrial Chemistry.

The derivatization of pillar[n]arenes is a prerequisite for endowing them with functions, as well as enriching the application of pillar[n]arene materials in advanced material science. Herein, we report the self-assembly of amphiphilic rim-differentiated pillar[5]arene (H₁). One side of the pillar[5]arene is composed of hydrophilic poly(ethylene oxide) chains, benzene and azobenzene groups connected with ether bonds, and the other side is composed of ethoxy groups. In CHCl₃ solvent, the amphiphile H₁ self-assembled into spherical micelles, while in H₂O/THF mixed solvent H₁ self-assembled into nanorod-like assemblies. Interestingly, addition of a guest molecule composed of tetraphenylethene and hexanenitrile groups (G₁) to the CHCl₃ solution of H₁ produces large sheet aggregates via the strong π–π stacking of rod segments. The reversible transformation between the nanosheet assemblies of host–guest complexes and nanoparticles is achieved by addition of the guest molecule 1,4-butylamine (G₂) and pillar[5]arene with ethoxy groups as competitive molecules. Notably, worm-like and nanorod micelles of H₁ were constructed in H₂O/THF solution triggered by light irradiation, which assemblies can be used as photosensitive erasable writing materials. © 2023 Society of Industrial Chemistry.

This article reports the preparation of new mesoporous triazine-based organic polymers and their characterization. The polymers were synthesized via a nucleophilic condensation reaction between cyanuric chloride and bisphenols or aromatic diamine linkers. As a result, two types of triazine-based polymers were prepared: triazine-ether and triazine-amine polymers. The polymers reveal a mesoporous nature with surface area values ranging between 345 and 1275 m² g⁻¹ and mesopore volume between 0.273 and 1.03 cm³ g⁻¹. These values were determined from argon gas isotherms at 87 K. The pore size distribution also confirmed the micro–mesoporosity, which reached up to 3.0 nm for all polymers. The triazine-amine polymer shows good thermal oxidative stability up to 450 °C. Motivated by the mesopore size, the new polymers were also employed as palladium nanoparticle supports. The X-ray diffraction technique indicated the successful incorporation of palladium nanoparticles, and Fourier transform infrared measurements proved that the framework of the polymers was retained after forming palladium supports. To ensure the catalytic reactivity of palladium nanoparticles, we employed one example as a catalyst in a Suzuki coupling reaction. The catalyst exhibited remarkable recyclability, maintaining catalytic efficiency through seven cycles, thereby enabling the use of palladium-loaded triazine-based polymeric catalysts in a variety of organic reactions in future. © 2023 Society of Industrial Chemistry.

1,3-Dienes/styrene sequence-controlled copolymers are widely used as thermoplastic elastomers, transparent impact resin and synthetic rubber and other materials. In this work, the binary anionic copolymerization of styrene (S) and C5-dienes including 1,3-pentadiene (P, E/Z = 65/35) and isoprene (I) were studied in cyclopentyl methyl ether (CPME) ‘green’ solvent using n-BuLi as initiator, and the effects of copolymerization monomer ratio and polar additive (PA) on the copolymerization kinetics and monomer sequence distributions were investigated. The kinetic analysis results showed that all copolymerization systems were the first-order reaction and the C5-dienes/S could be quantitatively consumed. The addition of S or I was conducive to the efficient conversion of P. Although the addition of PAs had little effect on the polymerization rate, it had a great influence on the microstructure and sequence distribution of the copolymer. ¹H NMR tracking analysis showed that, for S/P copolymerization with different feeding ratios 1/3 < f_P < 2/3, the instant composition F_P in the copolymer remained relatively constant at 15% < F_P < 35% when the monomer conversion rate was below 60%, and thus the inevitable formation of P microblocks in subsequent polymerization sequences was observed. Additionally, similar sequence distributions were obtained in the case of I/P copolymerization systems. By contrast, S/I copolymerization conformed to the typical random copolymerization pattern, and the copolymerization activity of S was slightly higher than that of the I in CPME. The use of strong PAs such as 2,2-di(2-tetrahydrofuran)propane directly resulted in a change of monomer sequence from a random pattern to a gradual block pattern. Moreover, the 3,4-isoprene branch units were much more sensitive to solvent and PA than 1,2-pentadiene units for C5-dienes; also Fourier transform infrared and DSC analysis verified the microstructure and sequence analysis results mentioned above. In addition, the results of gel permeation chromatography showed that the copolymerization process in CPME had excellent controllable characteristics. © 2023 Society of Industrial Chemistry.

A strong and tough indole-based epoxy film driven by cation–π interaction is designed, evading the trade-off between stiffness and extensibility in epoxy resins. The film with high strength, toughness and effective anti-counterfeiting properties induced by cation–π interaction is promising in the development of the fields of aerospace and electronic devices. © 2023 Society of Industrial Chemistry.

Pressure-sensitive adhesives (PSAs) are essential components of a large number of commercial products. The immense range of substrates that are required to be bonded, coupled with the challenging adhesive properties that are required in many applications, requires the development of PSAs with controllable structure. In this review, the development of acrylic latexes for use in PSA applications is discussed, with a particular emphasis on how to adjust the synthetic process to control adhesive properties. Following a general introduction to PSAs, a brief overview of the fundamental rheological properties that control adhesive behavior is given. Subsequently, routes to improve PSA performance through controlling the polymerization process are described. Finally, more complex systems that involve structured latexes and multiphase hybrids are detailed. The review concludes with a summary of future challenges for the field. © 2023 Society of Industrial Chemistry.

The design and synthesis of catalysts loaded with active components has attracted considerable attention in current research owing to their exceptional catalytic performance. In this study, the focus was on the utilization of tin-loaded ZA molecular sieves, possessing remarkable adsorption properties, alongside the catalytic activity of tin. These catalysts were successfully prepared and employed for the synthesis of poly(lactic acid) (PLA) from lactic acid derived from non-food biomass. By modifying the treatment of ZA molecular sieves, the properties of tin-loaded ZA molecular sieves were adjusted. The resulting catalysts exhibited a high tin capacity ranging from 2.29% to 2.81% and featured abundant mesoporous structures, providing a surface area of up to 341.2 m² g⁻¹. Regarding the preparation of PLA, our findings demonstrated that ZA-III-Sn²⁺ as a catalyst yielded PLA with a higher weight-average molecular weight (M_w) up to 2.57 × 10⁴ g mol⁻¹ and a higher yield of 65.3% compared to other catalysts. Moreover, the most optimal catalytic effect was achieved by adding the catalyst in three separate stages. Moreover, the amount of catalyst, reaction temperature and reaction time were found to influence both the molecular weight and yield of PLA. This study not only provides a valuable strategy for the preparation of loaded catalysts for PLA production but also offers new insights into the overall preparation process of PLA. © 2023 Society of Industrial Chemistry.

Biobased epoxy resins are gaining attention as a renewable alternative to petroleum-based resins. However, their inherent flammability requires flame-retardant treatment. In this study, hexaphenoxycyclotriphosphazene (HPCP) and various synergists were utilized to improve the flame retardancy of lignin-based epoxy resin (EP-L). Results showed that (3-aminopropyl)triethoxysilane (APTES) had the most effective synergistic effect for HPCP to form a P/N/Si-containing system, resulting in a compact crosslinked char layer. Upon the incorporation of HPCP and APTES (6∶1, 12 wt% of EP mass) into EP, a V-0 classification was achieved in the UL-94 vertical burning assessment, with a limiting oxygen index of 33.6% and a 47.77% decrease in the peak of heat release rate. This system minimally influenced the tensile strength of the composite (a 16.51% reduction), and maximumly increased its initial degradation temperature by 83 °C, compared with EP-L. © 2023 Society of Industrial Chemistry.