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Abstract: A new electrochromic norbornene derivative (NB) containing symmetrical diphenylamine and unsymmetrical triphenylamine groups, was synthesised from norbornene amine and unsymmetrical triphenylamine-substituted bromide. NB was used to obtain unsaturated PNB via ring-opening metathesis polymerization using different Grubbs'' catalysts, followed by hydrogen reduction to obtain saturated HPNB. PNB and HPNB were highly soluble in common organic solvents such as toluene, xylene, benzene, chlorobenzene, 1,2-dichlorobenzene, and tetrahydrofuran at room temperature. The glass transition temperatures (T g ) of PNB and hydrogenated HPNB were 162 °C and 117 °C, respectively. The 10% weight-loss temperatures of PNB and hydrogenated HPNB were 410 °C and 450 °C, respectively. Cyclic voltammogram of HPNB film cast onto an indium-tin oxide (ITO)-coated glass substrate exhibited three reversible oxidation redox couples at 0.52, 0.85 and 1.30 V versus Ag/Ag+ in acetonitrile solution. The electrochromic characteristics of HPNB showed excellent stability and reversibility, with multi-staged colour changes from light yellow to green, dark-blue and purple as the potential changed from 0 to 1.35 V. The colour switching time and the bleaching time of the HPNB were 8.7 s and 4.3 s, respectively, at 1084 nm and 7.9 s and 3.8 s at 879 nm. [Copyright &y& Elsevier]

Polymer properties along with recycling processes remain a constant challenge for post-recycled polymers. In this study, the development of recycling feasibility, monomers reactivity, and the chemical-recycled polymer properties from polycarbonate (PC) waste were demonstrated. Through selective aminolysis under mild conditions, the reduced molecular-weight products (or monomer mixtures) with newly incorporated flexible-ether linkages as building blocks were realized. By using the commodity monomers such as isocyanate reagents, monomer mixtures were readily to be re-connected into polyurethanes in one-pot process without prior purification of the recycled monomer mixtures. Due to the presence of urethane groups, the enhanced reactivity of the terminal phenolic hydroxyl groups of the monomer mixtures toward isocyanate groups would afford high molecular weights over ~80,000 g/mol for thermoplastic polyurethanes (TPUs). Moreover, by taking advantage of low melting point polyether-type polyols along with optimizing processing conditions, the TPUs exhibited a unique phase separation morphology with domain sizes ranging from ~10 nm to ~25 nm as investigated by using small angle X-ray scattering (SAXS) measurements. This work demonstrate that the PC waste was fully transformed into TPUs which exhibited improved elastomeric properties. This work demonstrates that the PC waste was depolymerized to monomer mixtures and subsequently transformed into recyclable thermoplastic polyurethanes exhibiting robust elastomeric properties. Image 1 • Monomer mixtures derived from the aminolysis of polycarbonates. • Thermoplastic polyurethane elastomers prepared from recycled monomer mixtures. • Diphenolic carbamates as hard segments for TPUs. • Ｍicrophase separation and semi-crystallinity morphologies. • Tensile properties comparable with those of TPUs prepared from pristine raw materials. [ABSTRACT FROM AUTHOR]

Over the years, the manipulation of polymer microphase separation associated with molecular architectures has been holding great promise for rendering structure-property relationship. A series of poly (urea/malonamide) dendrons bearing rigid adamantanes in the periphery were developed to serve as branching hard segments (HS) for thermoplastic polyurethanes (TPUs) either in end-capping or pendant manner. Thermal properties, crystalline structures, and mechanical properties of the TPUs were investigated by DSC, X-ray scattering, and DMA, respectively. The introduction of the branching units with bulky adamantanes would expectedly hinder the crystallization of HS. Intriguingly, the dendrons not only accelerate the crystallization of the soft segment (SS, based on polycaprolactone polyol (PCL)), but promote the phase separation between HS and SS to form distinct microdomains as well. These enhanced effects revealed a size-dependent relationship with growing size (or generation) of the branching HS. With the high SS crystallinity that can freeze the chain mobility and the robust HS domains that work as the physical crosslinking points, the resulting TPUs incorporated with adamantane-bearing units show superior shape memory behaviors. This work demonstrates that the molecular engineering on the architectures can significantly tailor the microstructures and properties of thermal plastic polymers. Image 1 • Preparation of dendrons bearing rigid adamantanes in periphery. • Adamantane-containing dendrons as hard segments for TPUs. • The crystallization of hard segments in TPUs hindered by bulky branching units. • The crystallization of the soft segment accelerated by the presence of bulky dendrons. • Shape memory properties enhanced by distinct microphase separation in TPUs. [ABSTRACT FROM AUTHOR]

Water-dispersible polymers represent an evolved category in the chemical industry in terms of an eco-friendly technology to meet the desired performance and to reduce the use of volatile solvents. One of the major challenges in the development of water dispersible resins deeply relies on the emulsification process that often requires the ionization process or the use of additional surfactants. In this study, an efficient method for the preparation of amphiphilic comb-like poly(hydroxyaminoethers), which consists of hydrophobic epoxy resins as the backbone and hydrophilic polyethers as the side chains, were realized in the absence of catalysts or initiators. Different from the conventional epoxy resin dispersions prepared in the presence of surfactants, or through ionization process, these amphiphilic comb-like polymers exhibited self-dispersed properties to achieve stable non-ionic emulsions in the water. The hydrophilic contents of these comb-like poly(hydroxyaminoethers) could be easily tailored in a wide range from less than 20 wt% to over 65 wt%, along with glass transition temperatures ranged from −45 °C to ~ 50 °C. In addition, the emulsifying ability was facilitated via the variations of the polymer architectures and compositions. Anti-corrosion properties were also evaluated for these self-dispersible poly(hydroxyaminoether) emulsions. Image 1 • Preparation of amphiphilic comb-like poly(hydroxyaminoethers). • Amphiphilic comb-like polymers with self-dispersed properties in water. • Thermally stable at temperatures over 300 °C, featuring tunable T g s from −45 to 50 °C. • Water dispersible characteristics with a size of 0.13 μm and a polydispersity of 0.029. • Pass anti-corrosion tests on the steel surfaces according to ASTM B117. [ABSTRACT FROM AUTHOR]

Abstract: To improve the pervaporation performance of thin-film composite membranes, novel thin-film composite membranes were prepared via interfacial polymerization by reacting 5-nitrobenzene-1,3-dioyl dichloride (NTAC) or 5-tert-butylbenzene-1,3-dioyl dichloride (TBAC) with triethylenetetraamine (TETA) on the surface of a modified polyacrylonitrile (mPAN) membrane (TETA-NTAC/mPAN and TETA-TBAC/mPAN). The effect of the acyl chloride monomers chemical structure on the pervaporation separation of an aqueous ethanol solution was investigated. Attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectroscopy, X-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM) and water contact angle measurements were applied to analyze the chemical structure, surface chemical composition, surface roughness and hydrophilicity of the polyamide active layer of the composite membrane. To correlate the variations in the free volume of the polyamide active layers with the pervaporation performance, positron annihilation spectroscopy (PAS) experiments were performed with a variable monoenergetic slow positron beam. From the results of the PAS and XPS experiments, the S parameter, o-Ps annihilation lifetime τ 3 (corresponding to free volume size) and its intensity I 3 (corresponding to free volume concentration), the τ 3 and I 3 of TETA-NTAC polyamide layer (positron incident energy of 1–1.7 keV) were both higher than those of TETA-TBAC polyamide layer. The S parameter for TETA-NTAC polyamide layer was also higher than that of the TETA-TBAC polyamide layer even though the former was more crosslinking than that of the latter. In the aqueous ethanol solution dehydration experiments, the TETA-NTAC/mPAN membrane produced both a higher permeation rate and water concentration in the permeate than the TETA-TBAC/mPAN membrane. [Copyright &y& Elsevier]