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Acteoside (ACT) is an important medicinal component, but its content is scarce. To obtain higher purity of ACT, the adsorption method was used to purify it. In this study, a broad-pore-domain hyper-crosslinked polymer (BHP-Kae) was prepared to adsorb ACT from Cistanche tubulosa, which is a medicinal plant. BHP-Kae-3 possessed a unique broad-pore-domain structure. This structure reduced the transfer resistance of ACT and facilitated the rapid diffusion of ACT into BHP-Kae-3, increasing the adsorption capacity. In addition, the surface and pore channels of BHP-Kae-3 contained abundant functional groups (-OH, C=O), which provided a large number of adsorption sites and facilitated ACT adsorption, thereby improving selectivity. The experimental results showed that BHP-Kae-3 exhibited a good adsorption capacity for ACT; the adsorption capacity was 105.12 mg/g, and the selectivity was 3.41. This study demonstrates the potential for efficient separation of natural products using broad-pore-domain adsorbents.

In the original publication [...]

[This corrects the article DOI: 10.1371/journal.pone.0294121.].

The nanocomposites of polythiourethane (PTU) with Fe.sub.3O.sub.4 were fabricated via an isocyanate-free approach. The nanocomposites simultaneously had the reprocessing, shape memory and photothermal properties. First, a linear PTU carrying a plethora of thiol groups was synthesized via the ring opening polyaddition between a bicyclic trithiocarbonate and a poly (propylene oxide) diamine. In the meantime, the surfaces of Fe.sub.3O.sub.4 nanoparticles were functionalized with thiol groups. Second, the co-crosslinking between the linear PTU and the thiol-functionalized Fe.sub.3O.sub.4 was performed via the coupling of thiol radicals with a radical initiator. Notably, the nanocomposites of PTU with Fe.sub.3O.sub.4 were successfully obtained with the fine dispersion of Fe.sub.3O.sub.4 nanoparticle in PTU matrix. Compared to control PTU, the nanocomposites displayed the improved thermomechanical properties. More importantly, the nanocomposites had reprocessing properties. The dynamic exchange of disulfide bonds is responsible for the reprocessing behavior. Owing to the crosslinking with disulfide bonds, PTU had shape memory properties. Notably, the incorporation of Fe.sub.3O.sub.4 nanoparticles was capable of improving the shape memory properties. In addition, the nanocomposites displayed the photothermal properties with the incorporation of Fe.sub.3O.sub.4 nanoparticles. The photothermal conversion behavior can be utilized to trigger the shape recovery of the nanocomposites under near-infrared light irradiation and in a non-contact fashion.

Bacteria pose significant threats to human health, industrial production, and daily life, with widespread microbial contamination remaining a critical challenge for global public health. Conventional porous materials often suffer from insufficient antibacterial efficacy, necessitating the development of advanced antimicrobial systems. Herein, we report a synthetic strategy for fabricating chloride-regenerable porous tubular polymers (HCP-DMH-Cl) via a combination of Friedel–Crafts alkylation and nucleophilic substitution reactions. HCP was initially prepared through a crosslinking reaction via Friedel–Crafts alkylation using FeCl3 as the catalyst and benzyl alcohol as the monomer. SEM characterization was performed to validate the tubular architectural morphology of HCP. The polymeric N-halamine precursor, HCP-DMH, was subsequently obtained through stepwise bromomethylation and nucleophilic substitution modifications. Upon chlorination, HCP-DMH-Cl exhibited good antibacterial efficacy against both E. coli and S. aureus, coupled with favorable regenerability of its oxidative chlorine content. This approach paves the way for designing next-generation porous media with tailored antibacterial functionality and sustainable chlorine-release capabilities.

The synthesis of efficient and sustainable heterogeneous Pd-based catalysts has been an active field of research due to their crucial role in carbon–carbon coupling reactions. In this study, we developed a facile and eco-friendly in situ assembly technique to produce a PdFe bimetallic hyper-crosslinked polymer (HCP@Pd/Fe) to use as a highly active and durable catalyst in the Ullmann reaction. The HCP@Pd/Fe catalyst exhibits a hierarchical pore structure, high specific surface area, and uniform distribution of active sites, which promote catalytic activity and stability. Under mild conditions, the HCP@Pd/Fe catalyst is capable of efficiently catalyzing the Ullmann reaction of aryl chlorides in aqueous media. The exceptional catalytic performance of HCP@Pd/Fe is attributed to its robust absorption capability, high dispersion, and strong interaction between Fe and Pd, as confirmed by various material characterizations and control experiments. Furthermore, the coated structure of a hyper-crosslinked polymer enables easy recycling and reuse of the catalyst for at least 10 cycles without any significant loss of activity.

The paper analyses the effect of the solvent amount and nature on the structure and mechanical properties of hydrogels based on copolymers of 2-hydroxyethylmethacrylate (HEMA) with polyvinylpyrrolidone (PVP). The synthesis of pHEMA-gr-PVP copolymers was carried out by the copolymerization method in the presence of metal ions of variable oxidation states in solvents with various nature: water, dimethyl sulfoxide (DMSO), diethylene glycol (DEG), and cyclohexanol (HOCy). The structure of the copolymers was evaluated by the PVP grafting efficiency, its actual content in the copolymer, and the molecular weight between crosslinks (MC). Taking the example of water, an increase in the solvent content up to 50 mass parts causes an increase in the efficiency of PVP grafting, which occurs due to enhanced macromolecule mobility through the dilution of the starting composition, hence the decrease in its viscosity. It was established that the nature of the solvent significantly affects the crosslinking density of the polymer network in the series H2O, DEG, DMSO, HOCy, an increase in the MC is observed causing a decrease in the hardness and elasticity of hydrogels and an increase in their water-retention capacity and swelling coefficient. The obtained results prove the possibility of targeted regulation within wide limits of the structure and properties of hydrogels based on pHEMA-gr-PVP copolymers through control of polymerization conditions (selection of the type and concentration of solvent).

The gelation kinetics of agar aqueous solutions were studied by means of the viscosity flow curves using a coaxial Couette cylinder viscometer. The viscosity curves show an unusual sigmoidal trend or an exponential decay to a viscous steady state. An original theory of gelation kinetics was developed considering the coarsening of increasingly larger and more stable clusters due to Ostwald ripening and the breakup of clusters that were too large due to the instability of rotating large particles induced by the shear rate. The developed Bounded Ripening Growth model takes into account the trend of the viscosity curves by means of an autocatalytic process with negative feedback on aggregation according to the logistic kinetic equation, in which the constants k[sub.1](γ) and k[sub.−](ν) are governed by the surface tension and shear rate, respectively. A dimensionless equation based on the difference between the Weber number and the ratio of the inverse kinetic constant to forward constant, accounts for the behavior of the dispersed phase in equilibrium conditions or far from the hydrostatic equilibrium.

Carbon fiber-reinforced polyimide composites are critical for aerospace applications in high-temperature environments of 300–500 °C. However, conventional PMR-15- and PEPA-terminated polyimides are limited by their insufficient glass transition temperatures (T[sub.g]) and low crosslinking densities. This study proposes a reactive backbone construction strategy by employing 4,4′-(ethyne-1,2-diyl)diphthalic anhydride (EBPA) as a difunctional monomer copolymerized with asymmetric 2,3,3′,4′-biphenyl tetracarboxylic dianhydride (α-BPDA) and 4,4′-oxydianiline to synthesize polyimide resins containing both backbone ethynyl and terminal phenylethynyl groups. The effects of EBPA content on the curing behavior, thermomechanical properties, and elevated temperature mechanical performance were systematically investigated. The incorporation of EBPA significantly elevated T[sub.g] from 378 °C to 486 °C. Compared to the EBPA-0 control, the optimized EBPA-2 composite exhibited 7.3% and 3.6% improvements in room temperature flexural strength and modulus, respectively. Notably, at 400 °C, EBPA-2 demonstrated retention rates of 69.9%, 93.7%, and 61.6% for flexural strength, flexural modulus, and interlaminar shear strength, exceeding EBPA-0 by 16.9, 8.9, and 18.6 percentage points. SEM analysis confirmed the effective suppression of interfacial debonding at elevated temperatures. These findings elucidate the structure–property relationships between molecular structure, T[sub.g], and short-term high-temperature mechanical retention, providing a promising resin matrix for advanced aerospace carbon fiber composites.

In this contribution, we reported the synthesis of the nanocomposites of poly(n-butyl acrylate) with Fe[sub.3]O[sub.4] nanoparticles (NPs) via dynamic crosslinking of poly(n-butyl acrylate)-grafted Fe[sub.3]O[sub.4] NPs with hindered urea bonds (HUBs). Towards this end, the surfaces of Fe[sub.3]O[sub.4] NPs were grafted with poly(n-butyl acrylate-ran-2-(3-tert-butyl-3-ethylureido)ethyl acrylate) chains [denoted as Fe[sub.3]O[sub.4]-g-P(BA-r-TBEA)] via living radical polymerization. Thereafter, 1,2-bis(tert-butyl)ethylenediamine was used as a crosslinker to afford the organic–inorganic networks with variable contents of Fe[sub.3]O[sub.4] NPs and crosslinking densities. It was found that the fine dispersion of Fe[sub.3]O[sub.4] NPs in the matrix of poly(n-butyl acrylate) was achieved. The nanocomposites exhibited excellent reprocessing properties, attributed to the introduction of HUBs. Owing to the crosslinking, the nanocomposites displayed excellent shape memory properties. Further, the nanocomposites possessed photo- and magnetic–thermal properties, which were inherited from Fe[sub.3]O[sub.4] NPs. These functional properties allow triggering the shape shifting of the nanocomposites in an uncontacted fashion.