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Water‐soluble monomers are extensively used in the production of polymeric materials in aqueous media for various applications. Acrylic acid–polyethylene glycol 2‐methyl‐2‐propenyl ether (AA‐HPEG) copolymers belong to the class of comb‐like polycarboxylate ether (PCE) polymers, employed as superplasticizers for cementitious materials. Due to different reactivity ratios of AA and HPEG, semibatch operations with optimized monomer addition profiles are required to enhance the incorporation of HPEG into the copolymer. The kinetics of this system is complex and, like other water‐soluble monomers, depends on monomer concentration, pH, and ionic strength. Despite its high‐volume industrial usage, the kinetics of this system have received little attention in the literature. Furthermore, the presence of the HPEG, with 55 ethylene oxide (EO) units in the side chain, complicates the precise determination of individual monomer conversions. To address this, various characterization methods are evaluated, including proton nuclear magnetic resonance (1H‐NMR) and size‐exclusion chromatography (SEC). Results show that HPEG conversion is determined more accurately using 1H‐NMR signals from the polymer than unreacted monomer signals or SEC traces. Aqueous semibatch AA‐HPEG copolymerization experiments are conducted in acidic media to investigate the effects of comonomer feeding time, initiator and chain‐transfer agent concentrations on the copolymerization kinetics, HPEG incorporation, and molar mass. [ABSTRACT FROM AUTHOR]

In recent years, the design and synthesis of high-performing conjugated materials for the application in organic photovoltaics (OPVs) have achieved lab-scale devices with high power conversion efficiency. However, most of the high-performing materials are still synthesised using complex multistep procedures, resulting in high cost. For the upscaling of OPVs, it is also important to focus on conjugated polymers that can be made via fewer simple synthetic steps. Therefore, an easily synthesised amorphous thiophene−quinoxaline donor polymer, TQ1, has attracted our attention. An analogue, TQ-EH that has the same polymer backbone as TQ1 but with short branched side-chains, was previously reported as a donor polymer with increased crystallinity. We have synthesised copolymers with varied ratios between octyloxy and branched (2-ethylhexyl)oxy-substituted quinoxaline units having the same polymer backbone, with the aim to control the aggregation/crystallisation behaviour of the resulting copolymers. The optical properties, glass transition temperatures and degree of crystallinity of the new copolymers were systematically examined in relation to their copolymer composition, revealing that the composition can be used to fine-tune these properties of conjugated polymers. In addition, multiple sub-Tg transitions were found from some of the polymers, which are not commonly or clearly seen in other conjugated polymers. The new copolymers were tested in photovoltaic devices with a fullerene derivative as the acceptor, achieving slightly higher performances compared to the homopolymers. This work demonstrates that side-chain modification by copolymerisation can fine-tune the properties of conjugated polymers without requiring complex organic synthesis, thereby expanding the number of easily synthesised polymers for future upscaling of OPVs. [ABSTRACT FROM AUTHOR]

Dipropargyl ether of bisphenol A (DPEBA) was used to copolymerize with 1, 3-diethynylbenzen (m-DEB) through dimethylsilane linkage in one-pot way to obtain the silicon-containing poly(diethynylbenzene-co-dipropargyl ether of bisphenol A)s (PSAPEs) by Grignard reagents. The reactivity of alkynyl hydrogens in DPEBA and m-DEB were calculated. The reactivity of DPEBA and m-DEB are so similar that they can easily copolymerize with each other to obtain a random copolymer. The content of copolymer segments in the copolymer is larger than that of homopolymer segments in the copolymer when the molar ration of DPEBA in the comonomer composition is less than 50%. With increase of DPEBA content in comonomer composition, the meltability of PSAPEs can be improved, but the curing temperature of PSAPEs increase, and the thermal stability of the cured PSAPEs decrease clearly. The flexural and interlaminar shear strength of the T300 carbon cloth reinforced PSAPEs composites (T300CF/PSAPEs) increase with incorporation of DPEBA in the copolymer matrix. The glass transition temperature of the composites can be over 400 °C. A T300CF/PSAPE-70 composite with 70% of DPEBA as comonomer of the matrix resin displays the flexural strength of 374 MPa at room temperature, and can retain over 88% at 300 °C in 30 min. [ABSTRACT FROM AUTHOR]

Thermally-assisted hydrolysis and methylation-gas chromatography-mass spectrometry (THM-GC-MS) using tetramethylammonium hydroxide (TMAH) is an effective approach for the characterization of condensation polymers with ester linkages such as ultraviolet (UV)-cured acrylate resins. However, for intractably cured acrylic resins, reliable structural characterization is often difficult by conventional THM-GC-MS owing to insufficient THM reactions. In this study, a pretreatment to effectively improve THM efficiency was proposed, in which the resin sample was preliminarily soaked and dissolved in a TMAH-methanol solution in a microtube. An aliquot of the TMAH solution was then introduced into the pyrolyzer at 400 °C to produce THM-GC-MS. The effectiveness of the proposed pretreatment was demonstrated using a UV-cured acrylate copolymer consisting of bulky and high-molecular weight bifunctional acrylate (9,9-Bis[4-(2-acryloyloxy ethoxy) phenyl]fluorene) and monofunctional acylate (2-(9 H-Carbazol-9-yl)ethyl acrylate) monomers, for which THM reactions did not proceed efficiently in conventional THM-GC-MS. Conversely, by the modified THM-GC-MS process with a pretreatment involving immersion at room temperature for 24 h or at 60 °C for 30 min, the characteristic decomposition products for each monomer unit were clearly observed in the chromatograms, and the copolymer composition could be precisely estimated from the relative yields of the observed decomposition products. In addition, a methyl acrylate peak, formed from unreacted acrylate moieties in the photocured copolymer, appeared in the chromatogram. Its relative yields were correlated to the double bond conversion in the cured sample. The observed results were successfully interpreted to clarify the curing process of the photocured acrylate copolymer samples. [Display omitted] • A THM-GC-MS method applicable to intractable UV-cured acrylate was developed. • The cured resin sample was preliminarily immersed and dissolved into a TMAH solution. • The copolymer composition of the intractable acrylate resin was precisely determined. • The double bond conversion was estimated by the modified THM-GC-MS method. • The observed results were interpreted in terms of the photocuring reactions. [ABSTRACT FROM AUTHOR]

[Display omitted] • Pickering emulsions are stabilized by diblock biodegradable copolymer micelles. • Pickering emulsion type and microstructure are adjusted by block ratio of copolymer. • The multiple microstructure of double-Pickering emulsions in one step is robust. Poly(ethylene glycol)- b -poly(ε -caprolactone) diblock copolymers (PEG- b -PCL) with predesigned hydrophilic/hydrophobic block length ratios have been synthesized and self-assembled to form micelles, then used to emulsify medium-chain triglycerides with an aqueous phase. The morphologies and sizes of PEG- b -PCL copolymer micelles have been characterized by transmission electron microscopy and dynamic light scattering. Interfacial tension testing between micellar dispersions and oil, combined with water contact angle measurements, have been performed to assess the ability of these micelles to adjust interfacial tension and micellar hydrophobicity, respectively. Relationship between the wettability of PEG- b -PCL copolymer micelles and their emulsification properties has been proved through phase diagram, optical microscopic observation, droplet sizes evolution and phase separation behavior of Pickering emulsion samples. Results show that both oil-in-water and water-in-oil Pickering emulsions, as well as water-in-oil-in-water (W/O/W) double-Pickering emulsions, may be controllably prepared through one-step homogenization. Double microstructure of W/O/W Pickering emulsion has proved to be extremely stable during long-term storage. [ABSTRACT FROM AUTHOR]