Macromolecular Rapid Communications最新文献

Herein, a new synthetic access to poly(arylene-1,2-diarylvinylene) (PAV-DA) derivatives is presented by a novel polyolefination of bifunctional N-tosylhydrazones using base-activated elemental sulfur. PAV-DAs are particularly interesting due to their aggregation-induced emission (AIE) properties, resulting in high solid-state photoluminescence quantum yields. The presented procedure allows the successful synthesis of eight homopolymers and two copolymers with different arylene backbones and aryl side chains from easily accessible monomers, not requiring the use of expensive or highly hazardous materials. The polymers are obtained in good yields and number average molecular weights up to 26.9 kDa. Thermal analysis reveals exceptionally high thermal stability with degradation temperatures as high as 541 °C and glass transition temperatures of up to 263 °C. Furthermore, it is found that the polymer properties are easily adjustable via copolymerization.

A series of cellulose networks are designed by reversibly crosslinking amino-functionalized 2-hydroxyethyl cellulose (HEC-NH₂) with different amounts of vanillin dimer (VA-CHO). The Schiff base reaction between amino-and aldehyde groups creates networks (SBHEC) bridged with crosslinks containing dynamic imine groups. These SBHEC networks can be hot pressed to flexible films with good thermal stability and solvent resistance, including notable stability in water, opposite to water-soluble HEC and HEC-NH₂. Compared to HEC-NH₂, the cross-linked SBHEC networks exhibit higher glass transition temperatures, elastic modulus, and tensile stress at break, and slightly reduced tensile strain at break. Reprocessing of the SBHEC networks is achieved through hot pressing under facile conditions, leading to good recovery of mechanical properties. Furthermore, the materials can be chemically recycled in a closed-loop by imine-hydrolysis under acidic conditions at room temperature. This releases the original building blocks HEC-NH₂ and VA-CHO, which can be recured to produce new SBHEC. This work highlights the potential of dynamic covalent cellulose networks as mechanically and chemically recyclable materials, contributing to the development of closed-loop recycling systems.

Considering the growth and applicability of the polymer industry over the years, alternative polymerization methods can be developed to facilitate simpler, rapid, and efficient polymer synthesis. This can be done via the utilization of radicals from microplasma interactions, proposing a simple initiator-free approach for both polymer and nanocomposite synthesis. In this study, microplasma-assisted synthesis of poly(2-Acrylamido-2-methylpropane sulfonic acid) (PAMPS_M) and poly(2-hydroxyethyl methacrylate) (PHEMA_M) is achieved under ambient conditions through radicals from the plasma interactions. This rapid polymerization method leads to high polymerization yield in short duration (PAMPS_M: 77.57% in 1 h; PHEMA_M 20.74% in 20 min) and long chain polymer formation (Mn: 2.23×10⁶ Da (PAMPS_M); 7.12×10⁴ Da (PHEMA_M)). The remarkable result in microplasma-assisted polymer synthesis is followed by formation of microplasma-synthesized PAMPS/Nitrogen-doped Graphene Quantum Dots (PAMPS/NGQDs_M) and PHEMA/NGQDs_M nanocomposites in one-pot two-step method. NGQDs addition contributes to luminescence properties of both nanocomposites (Photoluminescence emission/excitation: 540/460 nm (PAMPS/NGQDs_M); 505/410 nm (PHEMA/NGQDs_M)) and enhancement in mechanical properties by the formation of the covalent complex structure of polymer-nanomaterial. By unveiling a rapid, facile, and efficient method to radically polymerize water-based polymer and nanocomposite via microplasma, the present study will stimulate and advance further research on the preparation of rubber-based sol-gel via eco-friendly methods.

Rapid gelation hydrogels have garnered significant attention due to their simple synthesis, high efficiency, low cost, and environmental sustainability, which enable to meet critical demands for scalability and green chemistry for unlocking opportunities across diverse application fields. This review synthesizes current advancements in the mechanisms driving rapid gelation, encompassing self-assembly processes, MXene-triggered gelation, redox-driven reactions, coordination chemistry, Schiff base reactions, and other innovative strategies. The discussion extends to their far-reaching applications, from advanced therapeutic platforms and high-performance energy devices to precision sensors and adaptive soft actuators. By critically evaluating recent progress and addressing existing challenges, this review not only deepens the understanding of rapid gelation mechanisms, but also provides scientific insights and practical guidance to foster interdisciplinary integration and drive material innovation in green synthesis technologies.

As the Internet of Things and artificial intelligence technologies have advanced, wearable technology has attracted significant attention from academia and industry. Hydrogel has already received much attention as an emerging candidate material for wearable devices due to its unique 3D network structure, excellent biocompatibility, and soft stretchability. It is aimed here to provide a comprehensive overview of the development of hydrogels for wearable applications. Here, the synthetic methods currently employed in wearable hydrogels are reviewed first, including physical crosslinking, chemical crosslinking, and multiple crosslinking. Then, strategies for optimizing the performance of wearable hydrogels are summarized from the perspectives of mechanical properties, electrical properties, thermal properties, and other characteristics such as biocompatibility, self-healing, and self-adhesion. The final section discusses the latest advances in the application of wearable hydrogels in personal protection, and the current shortcomings and challenges. Here, it is aimed to provide innovative insights for further development in this field by summarizing the current research hotspots and cutting-edge issues in wearable hydrogels.

This work introduces a vitrimeric shape-memory polymer (SMP) with inherent flame retardancy and self-healing capability. The multifunctional system is achieved by crafting a dynamic network through the strategic imination and methacrylation of a polyether diamine (PED). This strengthens PED with, both, dynamic imine bonds for reshaping and functional methacrylate groups for network formation. Further reaction with phosphorus-based acrylate allows precise tailoring of the network's mechanical and thermal properties along with flame retardancy. The key lies in the dynamic imine bonds, enabling SMP to exhibit remarkable vitrimeric behavior and self-healing functionality. The networks are deformed at high temperature (≈150 °C) for permanent shape change, providing exceptional reprogrammability. The inherent flame retardancy stems from the high phosphorus content, achieving an impressive limiting oxygen index (LOI) of 29% and a V-1 rating in the UL 94 vertical burning test. This groundbreaking research paves the way for a new generation of sustainable materials with exceptional multi-functionalities like flame retardancy, self-healing, and shape-memory.

Absolute helix-sense-selective polymerization of an achiral acetylene monomer (1) in one-handed helical channels created with helix-sense-selective decomposition of (±)-poly1 using circularly polarized light is realized with no chiral compounds. In addition, the relative optical yield (%ee) of the formed oligomers is controlled by those of the one-handed helical channels.

The emergence of dinuclear catalysts marks a significant milestone in the advancement of high-performance polyolefin materials. Featuring two active sites, these dinuclear catalysts dramatically enhance catalytic performances and the resultant properties of polyolefins when compared to their mononuclear alternatives. Such differences arise from pronounced cooperative effects, which include steric hindrance, influences from heteroatoms, agostic interactions, and the spatial arrangement of metal centres within dinuclear catalysts. This review summarizes the progress made in the design of dinuclear metal catalysts specifically for olefin polymerization over the past decade. It further delves into the mechanisms underlying these cooperative effects by drawing comparisons with mononuclear analogues, thereby illuminating how these interactions drive distinctive catalytic behaviors. The insights presented herein are intended to inform the future development of dinuclear metal catalysts, proposing practical strategies for their optimisation and application. Additionally, this review addresses the challenges associated with the development of dinuclear catalysts for olefin polymerization, highlighting areas for further exploration.

Stable carbonized microspheres can readily be obtained with highly efficient char yields of close to 60% from photopolymers based on photo-induced Diels-Alder step growth polymerizations of α-methoxy benzaldehyde and bismaleimide precursors. The current study carefully elucidates the chemical decomposition pathways during the pyrolysis of the microspheres that yield excellent char yields via thermogravimetric analysis (TGA) and infrared (IR) spectroscopy. The high char yield and low shrinkage of close to 33% make Diels-Alder-type photopolymers a promising system for the next generation of additively manufactured carbon (AMcarbon) precursors.

High thermal conductivity liquid crystal epoxy resins (LCERs) and their composites are essential for efficient thermal management in electronic devices. The production of LCERs currently depends on combining epoxy monomers and hardeners or catalysts. However, these curing agents or catalysts destroy the liquid crystal phase in the crosslinked network, thereby limiting the thermal conductivity of LCERs. Here, a novel self-curing strategy is developed by incorporating a Schiff base into liquid crystal epoxy monomers, enabling the curing of monomers without additional agents or catalysts. This self-curing method effectively retains the ordered liquid crystal phase in the LCERs. Therefore, the self-cured LCEP-SC resin achieves a thermal conductivity of 0.36 W mK^-1, 133% higher than amine-cured LCEP-DDM, ≈1.8 times higher than that of general bisphenol A epoxy resin (E51-DDM, 0.2 W mK^-1). LCEP-SC-BN composites with 10 wt.% BN further exhibit a thermal conductivity of 0.61 W mK^-1, surpassing LCEP-DDM-BN composites by 42%. Additionally, the dynamic Schiff base structure allows LCERs degradation in acidic DMF/water solutions, enabling efficient recovery of BN fillers. This self-curing strategy provides a sustainable pathway for developing high thermal conductivity LCERs and their composites, offering enhanced thermal conductivity and recyclability for advanced electronic applications.