Macromolecular Chemistry and Physics最新文献

Benzocyclobutene (BCB) stands out as a compound of remarkable structural distinction, featuring a thermodynamically stable benzene ring coupled with a kinetically dynamic four-membered ring. This unique structure allows for ring-opening reactions under specific conditions, leading to the formation of crosslinking products. The primary initiation for the ring-opening of the four-membered ring in BCB is heat, although mechanical stress and light exposure can also trigger this transformation. This ability has catapulted it to prominence in the field of polymer material development. It has spurred the creation of a vast array of polymers that incorporate BCB groups either in their main chains or side chains, showcasing BCB's extensive applicability as a crosslinking agent. Additionally, BCB-based polymers (BCB polymer) exhibit a suite of desirable properties, such as exceptional dielectric characteristics, chemical and thermal resilience, minimal thermal expansion, and low moisture uptake. These attributes render them particularly suitable for a range of applications, including electronic packaging, silicon-based photonic integration, flat panel display technology, biomedical devices, and beyond. This paper delves into the various methods of inducing ring-opening crosslinking in BCB, summarizes the recent advancements in performance enhancement of BCB polymer materials, and examines their wide applications in different fields.

One possible way to store the excess CO₂ present in atmosphere is to use it as a reagent for the synthesis of commodities. In particular, CO₂ and epoxides can be copolymerized to produce a large variety of polycarbonates which appear very promising in various application fields. Further, the addition of an appropriate transfer agent in the reaction mixture promotes the formation of telechelic polycarbonates which can be used where specific functional polymers are necessary. In this work, (hydroxyethyl) methacrylate and 2-hydroxyethyl-2-bromoisobutyrate species are exploited as transfer agents in the copolymerization of CO₂ and cyclohexene oxide, in the presence of a macrocyclic phenolate dimagnesium catalyst. The effect of the transfer agent concentration on the polycarbonate characteristics is evaluated. Finally, the obtained telechelic polycarbonates are used as macromonomers and macroinitiators in the synthesis of statistical and block copolymers.

The relentless increase in global energy consumption, coupled with the detrimental effects of over-reliance on non-renewable fossil fuels, has necessitated a paradigm shift in the energy industry towards sustainable energy sources. Thermoelectric materials have emerged as a promising avenue for harnessing waste heat, offering a viable solution to the dual challenges of energy scarcity and environmental pollution. Compared with traditional electronic thermoelectric materials, ionic thermoelectric (i-TE) materials have received increasing attention. This review provides an overview of the recent advancements in i-TE materials based on the thermodiffusion effect, including an in-depth analysis of the fundamental principle, material design, and potential applications. The significance of material selection is highlighted, with types of i-TE materials ranging from liquid to quasi-solid and solid states, each presenting unique advantages and challenges. The innovative microstructural engineering and regulating interactions are identified as key strategies to enhance the thermoelectric performance of i-TE materials. Furthermore, the applications in capacitors and generators and sensing devices are summarized, demonstrating their potentials in varieties of scenarios. Encouraged by the recent rapid progresses, it is believed that the ionic i-TE materials and related technology are expected to generate practical impacts in the future solutions for sustainable energy.

With the development of new energy vehicles, there is a growing demand for automotive interior materials that meet higher standards. In this case, thermoplastic elastomer (TPE), being a completely recyclable environment-friendly polymer material, possesses advantages such as plasticizers and solvents free, excellent mechanical properties, less volatile organic compounds (VOC) release and low processing cost compared with polyvinyl chloride (PVC), polyurethane (PU), and thermoplastic polyolefin (TPO) skins, become a desirable choice for automotive injection molding automotive skin. Hence, this work investigates the influence of hydrogenated styrene-butadiene-styrene block copolymer (SEBS) molecular weight, chemical structure, and polypropylene (PP) doping amount on thermodynamic, crystallinity, rheological, and mechanical properties of TPE, which provides a scientific basis for guiding the material selection of TPE injection molding skin.

The new halogen-free donor polymer PCN6 is constructed using 2-ethylhexyl-4,6-dibromo-3-cyano-thieno[3,4-b]thiophene as acceptor (A) block, and is compared in detail with the commercially available PTB7-Th. It is found that PCN6 has a wider film absorption (300–700 nm) and lower highest occupied molecular orbital (HOMO) energy levels (−5.52 eV) than PTB7-Th (−5.34 eV), suggesting a great advantage of the monocyano-functionalized modification strategy in terms of molecular absorption and energy level tuning. The performance difference between PCN6:Y6- and PTB7-Th:Y6-based organic solar cells (OSCs) is compared by a series of studies including light intensity dependence, carrier mobility, AFM, TEM, and GIWAXS. The results show that PCN6:Y6-based OSCs have stronger crystallinity, better charge transport, higher and more balanced carrier mobility, and less exciton complex loss. Therefore, the power conversion efficiency (PCE) of PCN6:Y6-based OSCs reaches 11.34%, while the PCE of PTB7-Th:Y6-based OSCs is only 9.02%. These results suggest that 2-ethylhexyl-4,6-dibromo-3-cyano-thieno[3,4-b]thiophene is an excellent A block for the construction of halogen-free donor polymers with low HOMO energy levels, and also demonstrate that the introduction of cyano in the conjugated backbone of polymers is a good strategy to achieve high-performance OSCs.

This study investigates the surface functionalization of plastic substrates through dip-coating in azide-functionalized polymer solutions, followed by a click reaction (i.e., strain-promoted azide–alkyne cycloaddition). Acrylic, poly(ethylene terephthalate) (PET), and nylon substrates are dip-coated with a series of polymers containing various azide groups grafted onto the poly(methyl methacrylate-co-hydroxyethyl methacrylate) backbone to examine structural effects on the surface density of clickable azide groups. X-ray photoelectron spectroscopy and fluorescence spectroscopy confirm the subsequent click-immobilization of cycloalkyne-tagged fluorescein, which is quantified to calculate the surface density of clickable azide groups. Further investigations demonstrate that the surface density of azide groups can be controlled by manipulating the polymer ratio during dip-coating, thus enabling the preparation of a linear surface gradient in terms of azide group density. Finally, the microcontact printing (µCP) method is employed to pattern the functionalized surfaces and quantify the functional molecules immobilized on the surface by µCP. This study highlights the adaptability of click chemistry and polymer coating techniques for the advanced functionalization of plastic surfaces for materials science and engineering applications.

Polyimide (PI) is one of the most important engineering plastics, but its stability in aqueous environments is insufficient, which limits its anti-corrosion efficiency. In this study, a novel P(VDF-HFP)/SMT-RS@BNNSs/PI composite coating is prepared by incorporating poly(vinylidene fluoride-hexafluoropropylene) (P(VDF-HFP)) and the exfoliated boron nitride nanosheets (BNNSs) which were highly co-functionalized with two kinds of materials of the rosin and the soy-maleic anhydride-tannic acid adhesive molecules (SMT-RS@BNNSs). The coatings are characterized in detail by using the XRD, FT-IR, XPS, and SEM technologies. Electrochemical impedance spectroscopy (EIS) and polarization curve tests further evaluated the corrosion resistance of the coating. As results, the obtained P(VDF-HFP)/SMT-RS@BNNSs/PI coating with good adhesion (grade 1) to the low-carbon steel plate displays a larger water contact angle of 93.10° compared to blank PI (75.5°) and SMT-RS@BNNSs/PI (83.2°). The dispersed distribution and interaction of SMT-RS@BNNSs can effectively reduce the phase separation between P(VDF-HFP) and PI. Even after soaking in electrolyte for 15 days, the impedance modulus, corrosion current, and corrosion voltage of the P(VDF-HFP)/SMT-RS@BNNSs/PI coating are 1.568 × 10¹⁰ Ω cm², 4.612 × 10⁻¹² A cm⁻², and 0.325 V, respectively. These properties are superior to those of the PI and SMT-RS@BNNSs/PI coatings. It is believed that the excellent anti-corrosive performance of this PI-based composite will broaden the application fields of PI materials.