Journal of Polymer Science最新文献

Anthraquinones have been used as the organophotoredox catalysts to catalyze metal-free atom transfer radical polymerization (ATRP) under visible light irradiation. Polymers with different molecular weight and molecular weight distribution were obtained under different reaction conditions. The “living”/controlled nature of the polymerization was confirmed by the kinetic study, light on/off experiment and the block copolymer synthesis. The anthraquinones are found to catalyze ATRP via redox mechanism via sequential absorption of visible light. Evidence supported by control experiments showed that the excited anthraquinone radical anion or semiquinone anion generated by photo-induced single electron reduction or subsequent protonation and further reduction were responsible for the initiation/activation of the polymerization.

To expand the application fields of epoxy resins, there has been a growing demand for thermal latent curing agents that combine a lower curing temperature with a long storage lifetime for a one-component epoxy formulation. Herein, we present the use of novel thermal latent curing agents for epoxy resins that are effective at lower curing temperatures compared to epoxy resins containing imidazoles as curing agents—they are based on 4-(methylamino)pyridine (4MAPy), with reactivity suppressed by different amide protecting groups. We revealed reaction mechanism of epoxy polymerization by the thermal latent 4MAPy, using Matrix-assisted laser desorption ionization–time-of-flight mass spectrometry, Fourier transform infrared spectroscopy (FT-IR), and ¹H NMR analyses of the model polymerization of phenyl glycidyl ether. The amide protecting groups decomposed to form the highly reactive 4MAPy by nucleophilic acyl substitution with the propagating alkoxide. Furthermore, FT-IR data and pencil hardness tests revealed that thermal latent 4MAPy derivatives, particularly those with electron-rich pyridine rings, can cure epoxy resins at lower curing temperatures, notably 90°C. The thermal latent 4MAPy derivatives with epoxy resin exhibited a storage lifetime of at least 6 days at 3°C, in contrast to 4MAPy with epoxy resin that cured within a day after mixing.

A colorless, transparent thiol-ene polymer network was developed that contains cyclic phosphazene units in the polymer chain. Hexakis (allyloxy) cyclotriphosphazene (HAP) was synthesized from the nucleophilic substitution reaction of phosphonitrilic chloride trimer and allyl alcohol. Thiol-ene polymers (HAP-SH) were successfully prepared without by-products or the use of solvents through photopolymerization of the HAP and multithiol monomers with various functional group and flexible structures (e.g., 1,4-butanedithiol (BDTH), 1,3,5-benzenetrithiol (BTTH), trimethylolpropane tris (3-mercaptopropionate) (TTMP) and pentaerythritol tetrakis (3-mercaptopropionate) (PTTH)). The prepared HAP-SH polymers showed sufficient thermal stability due to the high degree of cross-linking. In addition, the HAP-SH polymer films exhibited high optical transparency of over 90% in the visible region. The refractive indices of the HAP-SH polymers measured at 637 nm were in the range of 1.5530–1.6344, and the Abbe number was calculated to be in the range of 34.5–47.1. These results are attributed to the structure of the cyclophosphazine and the polymer main chain containing aliphatic linkers with sulfur atoms. Another significant result was the transparency of the HAP-SH polymer films in the mid-infrared (MWIR) region. The thermal stability and excellent optical properties of the HAP-SH polymers make them good candidates for application as a protective film for IR lenses, which are easily damaged by external factors.

The cover image is based on the Research Article Synthesis and chiroptical properties of β-1,2-linked glycopolymers prepared by click polymerization by Misaki Suzuki et al., https://doi.org/10.1002/pol.20230746

In the cover image, Yasuhito Koyama and coworkers show the design, synthesis, and folding behaviors of β-1,2-linked glycopolymers as a bioconjugate-based foldamer. The glycopolymers are synthesized via the click polymerization of alkyne-containing β-glycosyl azides. The galactose-based polymer adopts a helically folded structure in ClCH₂CH₂Cl or THF. It is indicated that the glucose-based polymer can possibly form the helical folded structure in ClCH₂CH₂Cl at a low temperature region and adopt a random coil structure at 50 °C. In THF, the glucose-based polymer does not fold the conformation at all in the observed temperature region.

A new family of water-degradable elastic polymers prepared by oxidative crosslinking of the parent polythionolactones shows promise in a broad range of applications, but the compositions of these materials elude conventional analytical methods. Here we use sulfur K-edge X-ray absorption spectroscopy to quantify the amounts of thioether, disulfide, sulfone, sulfate ester, and thionoester in each polymer and to rule out the presence of several other functional groups, including sulfonate, thiosulfonate, sulfate, and sulfoxide. We rationalize this speciation as a function of linker flexibility in the context of sulfinyl cycloaddition reactions and propose a mechanism of aggregation for the oxidized polymers. Our results correlate with swelling ratios but not with porosity nor crosslink density measurements, demonstrating the importance of pairing mechanical and chemical techniques when characterizing heterogeneous organic polymers. Finally, we take advantage of the proximity of the gold M_4,5-edges to the sulfur K-edge to analyze the binding and reactivity of Au(III) with the crosslinked polymers.

One of the major challenges in expanding the uses of polymer materials is the development of thermally driven, multifunctional, self-healing water polyurethanes with superior mechanical properties. By adding nano-inorganic fillers and incorporating phenol-carbamate bonds into the molecular chains, a self-healing waterborne polyurethane with strong mechanical properties as well as antibacterial, and antiseptic properties was created. Given that tannic acid (TA) can create an isocyanate-group-containing phenol-carbamate network, the resulting TA-based water polyurethane (TWPU) had great mechanical properties and superior thermal stability with tensile strength of 31.9 MPa and elongation at break of 1406.4%. The amount of dynamic phenol-urethane linkages in the polyurethane backbone can also be adjusted and controlled to achieve excellent self-healing efficiency. The coating's anti-corrosion properties were good when the waterborne polyurethane was added to ZnO modified GO. Furthermore, the coating exhibited strong antibacterial capabilities due to the incorporation of nano-zinc oxide. In this study, we create an environmentally friendly waterborne polyurethane that is antibacterial, antiseptic, and self-healing using a straightforward and efficient design approach.

Poly(silylene arylether arylacetylene) (PSEA) resin is a promising material for preparing an advanced wave-transparent composite because of excellent thermal stability and good dielectric properties. Herein, a novel poly(silylene arylether arylacetylene) resin with trifluoromethyl groups (PSEAF) was synthesized by Grignard coupling reaction, and the effects of the incorporation of trifluoromethyl groups on various properties of PSEAF resin and quartz fiber reinforced composites were investigated. Compared to PSEA, the PSEAF resin exhibits better solubility and processability, and lower apparent activation energy for curing reactions. After thermal curing reactions, the PSEAF resin converts to an amorphous crosslinked network with the temperature at 5% weight loss (T_d5) around 470 °C. The cured PSEAF resin possesses improved mechanical properties and dielectric properties. The flexural strength arrives at 64.4 MPa, and the dielectric constant (ε) and dielectric loss (tanδ) at 30 MHz are 2.75 and 4.3 × 10⁻³, respectively. Besides, the quartz fiber reinforced PSEAF composite simultaneously shows ε of 3.3, theoretical wave transmittance |T|² of 91.4% at 7 GHz, and flexural strength of 350 MPa.

In this study, Trametes trogii-loaded poly(2- hydroxyethyl methacrylate) cryogel (Tt-PHEMA) was prepared and used as a biosorbent to remove Congo Red (CR), from aqueous solutions. The biomass and Tt-PHEMA cryogel were characterized with scanning electron microscopy and Fourier Transform infrared spectroscopy. Macroporosity degree (%) and swelling ratio (%) of the Tt-PHEMA cryogel were determined as 78.3% and 61.04%, respectively. The effect of loaded biomass amount, pH, initial CR concentration, temperature, and contact time were investigated detailedly. The maximum biosorption capacity of Tt-PHEMA cryogel was 156.71 ± 1.22 mg g⁻¹ at pH 6.0 at 45°C. Biosorption capacity was increased from 125.92 ± 1.524 mg g⁻¹ to 156.71 ± 1.22 mg g⁻¹ with increasing temperature from 25 to 45°C, demonstrating that the biosorption process was endothermic. The biosorption data were well fitted to the Freundlich isotherm and pseudo-second-order kinetic models. The negative Gibbs free energy change values showed favorable biosorption. The Tt-PHEMA cryogel was easily regenerated with ethanol and used repeatedly five times without a significant change in the biosorption capacity. As a result, Trametes trogii-loaded PHEMA cryogel has an application potential for CR removal from wastewater, taking advantage of interconnected macroporous structure cryogels.