Investigations on pyridinium salts as a solid‐state ionics

The object of this work is to prepare polymer poly(2vinylpyridine), P‐2VP, and its salts like P‐2VP‐HI, P‐2VP‐HIO₃, and P‐2VP‐HIO₄. The formation of P‐2VP salts was confirmed by IR and ¹H NMR techniques. Conductivities of these were determined in solid state at various temperatures from 30 to 90°C. Observations indicated that the addition of I^? or IO₃^? or IO₄^? ions affect the ionic conductivity of P‐2VP. Molecular mass determination and analytical results indicated that 94, 92.5, and 95% of the pyridine molecules in the P‐2VP chain were hydroiodated, iodated, and periodated, respectively, with the corresponding acids of iodine. The total ionic transport number and activation energy of the polymers were also determined. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Water Free Operated Phosphoric Acid Doped Radiation‐Grafted Proton Conducting Membranes for High Temperature Polymer Electrolyte Membrane Fuel Cells

The present study uses the radiation‐induced grafting method and applies it onto poly(ethylene‐alt‐tetrafluoroethylene) (ETFE) for the synthesis of proton‐exchange membranes by using monomers 4‐vinyl pyridine (4VP), 2‐vinyl pyridine (2VP), N‐vinyl‐2‐pyrrolidone (NVP) followed by phosphoric acid doping. Phosphoric acid that provides Grotthuss mechanism in proton mobilization is used to transform the graft copolymers to a high temperature membrane state. Resultant proton‐exchange membranes are verified with their proton conductivity, water uptake, mechanical and thermal properties, and phosphorous distribution as ex situ characterization. Our most important finding as a novelty in literature is that ETFE‐g‐P4VP phosphoric acid doped proton‐exchange membranes exhibit proton conductivities as 66 mS cm^–1 at 130 °C, 53 mS cm^–1 at 120 °C, 45 mS cm^–1 at 80 °C at RH 100% and 55 mS cm^–1 at 130 °C, 40 mS cm^–1 at 120 °C, 35 mS cm^–1 at 80 °C at dry conditions. Moreover, ETFE‐g‐P4VP membranes still conserves the mechanical properties, i.e., tensile strength up to 48 MPa. ETFE‐g‐P4VP membranes were tested in PEMFC at 80, 100, and 120 °C and RH <2% and exhibit promising performance as an alternative to commercial Nafion® membranes. The single cell testing performance of ETFE‐g‐P4VP membranes is presented for the first time in literature in our study.     

Oligo(ethylene oxide) side‐chain steric screening effects on conductimetric properties of grafted poly(4‐vinylpyridinium) salts in aqueous solutions

A set of poly[N‐oligo(ethylene oxide)yl 4‐vinylpyridinium tosylate] (P4VOEOOTs) has been prepared by spontaneous polymerization of 4‐vinylpyridine. This method gives a grafted polyelectrolyte having a positive charge on every backbone pyridinic moiety. The P4VP15Ts, P4VP164Ts, P4VP350Ts and P4VP750Ts aqueous solution conductivities were determined in the concentration range from 6 × 10^?4 to 10^?2 M at 25 °C. The variation of the conductivity versus concentration of the investigated system exhibits typical polyelectrolyte behaviour. The polyelectrolyte mobility was found to be dependent on the oligo(ethylene oxide) (OEO) side‐chain length. Manning's rod‐like model fails to describe these results. A simple steric effect is proposed to explain the influence of the OEO length. Copyright © 2003 Society of Chemical Industry     

Synthesis of new ionic crosslinked polymer hydrogel combining polystyrene and poly(4‐vinyl pyridine) and its self‐healing through a reshuffling reaction of the trithiocarbonate moiety under irradiation of ultraviolet light

A new ionic crosslinked polymer hydrogel was achieved by the strategy of ionically crosslinking α,ω‐dibromide terminated polystyrene (Br‐PS‐Br) with poly(4‐vinyl pyridine) (P4VP) which was synthesized by reversible addition‐fragmentation chain transfer polymerization using a chain transfer agent containing a trithiocarbonate moiety. The moiety of trithiocarbonate was introduced into the crosslinked network to show the self‐healing characteristics. The chain structure and components of Br‐PS‐Br and P4VP were characterized through ¹H NMR, gel permeation chromatography, Fourier transform IR spectroscopy and elemental analysis. The P4VP (M_n = 25 300 g mol^?1) chains were crosslinked with Br‐PS‐Br (M_n = 2000 g mol^?1) through the quaternization reaction to form a polymer network which was further crosslinked in acetonitrile by irradiation of UV light to fabricate a hydrogel. Such a hydrogel of P4VP/Br‐PS‐Br cut by a razor blade can be rapidly (1 h) and repeatedly (three times) healed through a reshuffling reaction of the trithiocarbonate moiety under irradiation by UV light. © 2018 Society of Chemical Industry     

Studies on blends of LLDPE and polar polymers compatibilized by a random copolymer

Compatibilization of blends of linear low‐density polyethylene (LLDPE)–poly(methyl methacrylate) (PMMA) and LLDPE–copolymer of methyl methacrylate (MMA) and 4‐vinylpyridine (poly(MMA‐co‐4VP) with poly(ethylene‐co‐methacrylic acid) (EMAA) have been studied. Mechanical properties of the LLDPE–PMMA blends increase upon addition of EMAA. In order to further improve interfacial adhesion of LLDPE and PMMA, 4‐vinyl pyridine units are introduced into PMMA chains, or poly(MMA‐co‐4VP) is used as the polar polymer. In LLDPE–poly(MMA‐co‐4VP)–EMAA blends, interaction of MAA in EMAA with 4VP of poly(MMA‐co‐4VP) causes a band shift in the infrared (IR) spectra. Chemical shifts of N_1s binding energy in X‐ray photoelectronic spectroscopy (XPS) experiments indicate a transfer of proton from MAA to 4VP. Scanning electron microscopy (SEM) pictures show that the morphology of the blends were improved upon addition of EMAA. Nonradiative energy transfer (NRET) fluorescence results attest that there exists interdiffusion of chromophore‐labeled LLDPE chains and chromophore‐labeled poly(MMA‐co‐4VP) chains in the interface. Based on experimental results, the mechanism of compatibilization is studied in detail. Compatibilization is realized through the interaction between MAA in EMAA with 4VP in poly(MMA‐co‐4VP). © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 71: 967–973, 1999     

Phase behavior of binary and ternary blends of poly(styrene‐co‐methacrylic acid), poly(styrene‐co‐4‐vinylpyridine), and poly(2,6‐dimethyl‐1,4‐phenylene oxide)

Poly(styrene‐co‐methacrylic acid) (PSMA) and poly(styrene‐co‐4‐vinylpyridine) (PS4VP) of different compositions were prepared and characterized. The phase behavior of these copolymers as binary PSMA/PS4VP mixtures or with poly(2,6‐dimethyl‐1,4‐phenylene oxide) (PPO) as PPO/PSMA or PPO/PS4VP and PPO/PSMA/PS4VP ternary blends was investigated by differential scanning calorimetry (DSC). This study showed that PPO was miscible with PS4VP containing up to 15 mol % 4‐vinylpyridine (4VP) but immiscible with PS4VP‐30 (where the number following the hyphen refers to the percentage 4VP in the polymer) and PSMA‐20 (where the number following the hyphen refers to the percentage methacrylic acid in the polymer) over the entire composition range. To examine the morphology of the immiscible blends, scanning electron microscopy was used. Because of the hydrogen‐bonding specific interactions that occurred between the carboxylic groups of PSMA and the pyridine groups of PS4VP, chloroform solutions of PSMA‐20 and PS4VP‐15 formed interpolymer complexes. The obtained glass‐transition temperatures (T_g's) of the PSMA‐20/PS4VP‐15 complexes were found to be higher than those calculated from the additivity rule. Although, depending on the content of 4VP, the shape of the T_g of the PPO/PS4VP blends changed from concave to S‐shaped in the case of the miscible blends, two T_g were observed with each PPO/PS4VP‐30 and PPO/PS4VP‐40 blend. The thermal stability of the PSMA‐20/PS4VP‐15 interpolymer complexes was studied by thermogravimetry. On the basis of the obtained results, the phase behavior of the ternary PPO/PSMA‐20/PS4VP‐15 blends was investigated by DSC. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Influence of LiClO4 on the thermal,mechanical, and morphological properties of P(DMS‐co‐EO)/ P(EPI‐co‐EO) blends

The UV‐vis absorption, thermal analysis, ionic conductivity, mechanical properties, and morphology of a blend of poly(dimethylsiloxane‐co‐ethylene oxide) [P(DMS‐co‐EO)] and poly(epichlorohydrin‐co‐ethylene oxide) [P(EPI‐co‐EO)] (P(DMS‐co‐EO)/P(EPI‐co‐EO) ratio of 15/85 wt %) with different concentrations of LiClO₄ were studied. The maximum ionic conductivity (σ = 1.2 × 10^?4 S cm^?1) for the blend was obtained in the presence of 6% wt LiClO₄. The crystalline phase of the blend disappeared with increasing salt concentration, whereas the glass transition temperature (T_g) progressively increased. UV‐vis absorption spectra for the blends with LiClO₄ showed a transparent polymer electrolyte in the visible region. The addition of lithium salt decreased the tensile strength and elongation at break and increased Young's modulus of the blends. Scanning electron microscopy showed separation of the phases between P(DMS‐co‐EO) and P(EPI‐co‐EO), and the presence of LiClO₄ made the blends more susceptible to cracking. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 1230–1235, 2004     

New generation of thermally stable and conducting poly(azomethine‐ester)s: nano‐blend formation with polyaniline

A new dihydroxy monomer, (E)‐1‐(4‐(4‐(4‐hydroxybenzylidene)thiocarbamoylaminobenzyl)phenyl)‐3‐(4‐hydroxybenzylidene)thiourea, was synthesized and polymerized with thiophene‐2,5‐dicarbonyl/terephthaloyl chloride. The structural characterization of the resulting polymers was carried out using spectral techniques (Fourier transform infrared and ¹H NMR) along with a physical property investigation. Novel polyesters are readily soluble in various amide solvents and possess high molar mass of 112 × 10³–133 × 10³ g mol^?1. The thermal stability was determined via 10% weight loss to be in the range 519–523 °C and the glass transition temperature was 286–289 °C. Electrically conducting poly(azomethine‐ester)‐blend‐polyaniline blends were prepared using mash‐blending and melt‐blending techniques. Materials obtained using the conventional melt‐blending approach generated an efficient conductive network compared with those produced by mash blending. Field emission scanning electron microscopy revealed a nano‐blend morphology for the melt‐blended system owing to increased physical interactions (hydrogen bonding and π–π stacking) between the two constituent polymers. Miscible blends of thiophene‐based poly(azomethine‐ester)‐blend‐polyaniline had superior conductivity (1.6–2.5 S cm^?1) and thermal stability (T₁₀ = 507 °C) even at low polyaniline concentration relative to reported thiophene/azomethine/polyaniline‐based structures. The new thermally stable and conducting nano‐blends could be candidates for various applications including optoelectronic devices. © 2012 Society of Chemical Industry     

The phase behavior and thermal stability of blends of poly(styrene‐co‐methacrylic acid)/poly(styrene‐co‐ 4‐vinylpyridine)

The hydrogen bonding and miscibility behaviors of poly(styrene‐co‐methacrylic acid) (PSMA20) containing 20% of methacrylic acid with copolymers of poly(styrene‐co‐4‐vinylpyridine) (PS4VP) containing 5, 15, 30, 40, and 50%, respectively, of 4‐vinylpyridine were investigated by differential scanning calorimetry, thermogravimetric analysis (TGA), and Fourier transform infrared spectroscopy (FTIR). It was shown that all the blends have a single glass transition over the entire composition range. The obtained T_gs of PSMA20/PS4VP blends containing an excess amount of PS4VP, above 15% of 4VP in the copolymer, were found to be significantly higher than those observed for each individual component of the mixture, indicating that these blends are able to form interpolymer complexes. The FTIR study reveals presence of intermolecular hydrogen‐bonding interaction between vinylpyridine nitrogen atom and the hydroxyl of MMA group and intensifies when the amount of 4VP is increased in PS4VP copolymers. A new band characterizing these interactions at 1724 cm⁻¹ was observed. In addition, the quantitative FTIR study carried out for PSMA20/PS4VP blends was also performed for the methacrylic acid and 4‐vinylpyridine functional groups. The TGA study confirmed that the thermal stability of these blends was clearly improved. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Poly(4‐vinyl pyridine)‐grafted graphene oxide for drug delivery and antimicrobial applications

Graphene oxide (GO) was covalently functionalized with poly(4‐vinyl pyridine) (P4VP) by atom transfer radical polymerization for drug delivery and antimicrobial applications. The physiochemical properties, chemical structure, composition and morphology of the P4VP‐functionalized GO (GO‐P4VP) were studied. Simple physisorption of a cancer drug, camptothecin (CPT), via π ? π stacking and/or hydrophobic interactions on the GO‐P4VP was tested for drug loading and its release by altering the pH. The GO‐P4VP has low cytotoxicity, and the CPT‐loaded GO‐P4VP exhibited a high potency for killing cancer cells in vitro. Prominent antimicrobial properties against Escherichia coli and Staphylococcus aureus were also observed. Thus, the GO‐P4VP can be utilized as a drug delivery vector with high biocompatibility, solubility and stability in physiological solutions, a suitable payload capacity and excellent bacterial toxicity. Owing to its small size, low cost, large specific area, ready scalability and useful non‐covalent interactions, GO‐P4VP is a novel material for biomedical, industrial and environmental applications. © 2015 Society of Chemical Industry     

Studies on polybenzimidazole/poly (4‐vinylpyridine) blends and their proton conductivity after doping with acid

In the present work, polybenzimidazole (PBI) and poly(4‐vinylpyridine) (P4VP) were chosen because they form miscible blends and both materials are suitable for acid doping as a matrix, which can eventually be used as proton conductor. The miscibility and inter‐polymer interactions were studied by infrared (IR) spectroscopy and differential scanning calorimetry (DSC). DSC and IR results suggest that PBI blended with P4VP exhibits good miscibility due to the strong hydrogen bonds formed between PBI's NH groups and P4VP's N: groups. The glass transition temperatures of the blends can be fitted to the Fox equation very well. The blends were also studied by thermogravimetry. Their thermal stability is slightly higher than that of P4VP, but is still lower than that of PBI. Temperature‐dependent conductivity of acid‐doped PBI/P4VP blends was studied. As the temperature increases, the conductivity of PBI/P4VP doped with H₃PO₄ increases. The temperature‐dependent conductivity of the blends follows a simple Arrhenius relationship when the P4VP content is low (less than 15%), while a non‐Arrhenius behaviour of the conductivity of the blends becomes more and more significant with increasing P4VP content. This means that the proton transport in the blends is controlled by both a hopping mechanism and the segmental motion of the polymer. The contribution of these two mechanisms depends on the P4VP content. Copyright © 2003 Society of Chemical Industry     

Mechanical properties and morphology of polylactide,linear low‐density polyethylene,and their blends

Melt blending of linear low density polyethylene (LLDPE) and polylactide (PLA) was performed in an extrusion mixer with post extrusion blown film attachment with and without compatibilizer‐grafted low density polyethylene maleic anhydride. The blend compositions were optimized for tensile properties as per ASTM D 882‐91. On the basis of this, LLDPE 80 [80 wt % LLDPE and 20 wt % poly(L ‐lactic acid) (PLLA)] and MA‐g‐low‐density polyethylene 80/4 (80 wt % LLDPE, 20 wt % PLLA, and 4 phr compatibilizer) were found to be an optimum composition. The blends were characterized according to their mechanical, thermal, and morphological behavior. Fourier transform infrared spectroscopy revealed that the presence of compatibilizer enhanced the blend compatibility to some extent. The morphological characteristics of the blends with and without compatibilizer were examined by scanning electron microscopy. The dispersion of PLLA in the LLDPE matrix increased with the addition of compatibilizer. This blend may be used for packaging applications. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Click chemistry‐type crosslinking of a low‐conductivity polyethylene copolymer ternary blend for power cable insulation

High‐voltage direct‐current power cables are vital for the efficient transport of electricity derived from renewable sources of energy. The most widely used material for high‐voltage power cable insulation – low‐density polyethylene (LDPE) – is usually crosslinked with peroxides, a process that releases unwanted by‐products. Hence, by‐product‐free crosslinking concepts that mitigate the associated increase in electrical conductivity are in high demand. Click chemistry‐type crosslinking of polyethylene copolymer mixtures that contain glycidyl methacrylate and acrylic acid co‐monomers is a promising alternative, provided that the curing reaction can be controlled. Here, we demonstrate that the rate of the curing reaction can be adjusted by tuning the number of epoxy and carboxyl groups. Both dilution of copolymer mixtures with neat LDPE and the selection of copolymers with a lower co‐monomer content have an equivalent effect on the curing speed. Ternary blends that contain 50 wt% of neat LDPE feature an extended extrusion window of up to 170 °C. Instead, at 200 °C rapid curing is possible, leading to thermosets with a low direct‐current electrical conductivity of about 10^?16 S cm^?1 at an electric field of 20 kV mm^?1 and 70 °C. The conductivity of the blends explored here is comparable to or even lower than values measured for both ultraclean LDPE and a peroxide‐cured commercial crosslinked polyethylene grade. Hence, click chemistry curing represents a promising alternative to radical crosslinking with peroxides. © 2019 Society of Chemical Industry     

Crystallization behavior of PEO in blends of poly(ethylene oxide)/poly(2‐vinyl pyridine)‐b‐(ethylene oxide) block copolymer

The crystallization behavior of two molecular weight poly(ethylene oxide)s (PEO) and their blends with the block copolymer poly(2‐vinyl pyridine)‐b‐poly(ethylene oxide) (P2VP‐b‐PEO) was investigated by polarized optical microscopy, thermogravimetric analysis, differential scanning calorimetry, and atomic force microscopy (AFM). A sharp decreasing of the spherulite growth rate was observed with the increasing of the copolymer content in the blend. The addition of P2VP‐b‐PEO to PEO increases the degradation temperature becoming the thermal stability of the blend very similar to that of the block copolymer P2VP‐b‐PEO. Glass transition temperatures, T_g, for PEO/P2VP‐b‐PEO blends were intermediate between those of the pure components and the value increased as the content of PEO homopolymer decreased in the blend. AFM images showed spherulites with lamellar crystal morphology for the homopolymer PEO. Lamellar crystal morphology with sheaf‐like lamellar arrangement was observed for 80 wt% PEO(200M) and a lamellar crystal morphology with grain aggregation was observed for 50 and 20 wt% blends. The isothermal crystallization kinetics of PEO was progressively retarded as the copolymer content in the blend increased, since the copolymer hinders the molecular mobility in the miscible amorphous phase. POLYM. ENG. SCI., 2012. © 2011 Society of Plastics Engineers     

Morphology and thermal behavior of organo‐bentonite clay/poly(styrene‐co‐methacrylic acid)/poly(isobutyl methacrylate‐co‐4‐vinylpyridine) nanocomposites

Poly(styrene‐co‐methacrylic acid) containing 29 mol % of methacrylic acid (SMA‐29) and poly(isobutyl methacrylate‐co‐4‐vinylpyridine) containing 20 mol % of 4‐vinylpyridine (IBM4VP‐20) were synthesized, characterized, and used to elaborate binary and ternary nanocomposites of different ratios with a 3% by weight hexadecylammonium‐modified bentonite from Maghnia (Algeria) by casting method from tetrahydrofuran (THF) solutions. The morphology and the thermal behavior of these binary and ternary elaborated nanocomposites were investigated by X‐ray diffraction, scanning electron microscopy, FTIR spectroscopy, differential scanning calorimetry, and thermogravimetry. Polymer nanocomposites and nanoblends of different morphologies were obtained. The effect of the organoclay and its dispersion within the blend matrix on the phase behavior of the miscible SMA29/IBM4VP20 blends is discussed. The obtained results showed that increasing the amount of SMA29 in the IBM4VP20/SMA29 blend leads to near exfoliated nanostructure with significantly improved thermal stability. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Effects of glycerol and PE‐g‐MA on morphology,thermal and tensile properties of LDPE and rice starch blends

The effects of glycerol and polyethylene‐grafted maleic anhydride (PE‐g‐MA) on the morphology, thermal properties, and tensile properties of low‐density polyethylene (LDPE) and rice starch blends were studied by scanning electron microscopy (SEM), differential scanning calorimetry, and the Instron Universal Testing Machine, respectively. Blends of LDPE/rice starch, LDPE/rice starch/glycerol, and LDPE/rice starch/glycerol/PE‐g‐MA with different starch contents were prepared by using a laboratory scale twin‐screw extruder. The distribution of rice starch in LDPE matrix became homogenous after the addition of glycerol. The interfacial adhesion between rice starch and LDPE was improved by the addition of PE‐g‐MA as demonstrated by SEM. The crystallization temperatures of LDPE/rice starch/glycerol blends and LDPE/rice starch/glycerol/PE‐g‐MA blends were similar to that of pure LDPE but higher than that of LDPE/rice starch blends. Both the tensile strength and the elongation at break followed the order of rice starch/LDPE/glycerol/PE‐g‐MA blends > rice starch/LDPE/glycerol > LDPE/rice starch blends. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 344–350, 2004     

Structure and properties of polyamide 6 blends with low‐density polyethylene grafted by itaconic acid and with neutralized carboxyl groups

A comparative study of the structure and properties of two‐phase blends of polyamide 6 (PA6) and low‐density polyethylene (LDPE) modified in the course of reactive extrusion, by grafting of itaconic acid (IA) without neutralization of carboxyl groups (LDPE‐g‐IA) and with neutralized carboxyl groups (LDPE‐g‐IA^?M⁺) was carried out. It was shown that 30 wt % of LDPE‐g‐IA^?M⁺ introduced to PA6 resulted in blends of higher Charpy impact strength compared with that of PA6/LDPE‐g‐IA blends. The maximum increase was achieved when Mg(OH)₂ was used as a neutralizing agent. The blend morphology has a two‐phase structure with blurred interphases because of increased adhesion between the phases. The neutralization of carboxyl groups in grafted IA did not lead to two‐phase morphology of blends, which had a negative influence on the mechanical properties. It is believed that the differences in the impact strength were caused by the influence of the added neutralizing agents on the structure of interphases, which depends on both the interfaces adhesion and structural effects resulting from the nucleating behavior of the neutralizing agent. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 1702–1708, 2004     

New low bandgap conjugated polymer derived from 2, 7‐carbazole and 5, 6‐bis(octyloxy)‐4, 7‐di(thiophen‐2‐yl) benzothiadiazole: Synthesis and photovoltaic properties

To develop conjugated polymers with low bandgap, deep HOMO level, and good solubility, a new conjugated alternating copolymer PC‐DODTBT based on N‐9′‐heptadecanyl‐2,7‐carbazole and 5, 6‐bis(octyloxy)‐4,7‐di(thiophen‐2‐yl)benzothiadiazole was synthesized by Suzuki cross‐coupling polymerization reaction. The polymer reveals excellent solubility and thermal stability with the decomposition temperature (5% weight loss) of 327°C. The HOMO level of PC‐DODTBT is ‐5.11 eV, indicating that the polymer has relatively deep HOMO level. The hole mobility of PC‐DODTBT as deduced from SCLC method was found to be 2.03 × 10^?4 cm²/Versus Polymer solar cells (PSCs) based on the blends of PC‐DODTBT and [6,6]‐phenyl‐C₇₁‐butyric acid methyl ester (PC₇₁BM) with a weight ratio of 1:2.5 were fabricated. Under AM 1.5 (AM, air mass), 100 mW/cm^?2 illumination, the devices were found to exhibit an open‐circuit voltage (V_oc) of 0.73 V, short‐circuit current density (J_sc) of 5.63 mA/cm^?2, and a power conversion efficiency (PCE) of 1.44%. This photovoltaic performance indicates that the copolymer is promising for polymer solar cells applications. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Multiple shape memory effects of trans‐1,4‐polyisoprene and low‐density polyethylene blends

A novel series of shape memory blends of trans‐1,4‐polyisoprene (TPI) and low‐density polyethylene (LDPE) were prepared using a simple physical blending method. The mechanical, thermal and shape memory properties of the blends were studied and schemes proposed to explain their dual and triple shape memory behaviors. It was found that the microstructures played an important role in the shape memory process. In TPI/LDPE blends, both the TPI crosslinking network and LDPE crystalline regions could work as fixed domains, while crystalline regions of LDPE or TPI could act as reversible domains. The shape memory behaviors were determined by the components of the fixed and reversible domains. When the blend ratio of TPI/LDPE was 50/50, the blends showed excellent dual and triple shape memory properties with both high shape fixity ratio and shape recovery ratio. © 2017 Society of Chemical Industry     

Blue fluorescent conductive poly(9,10‐di(1‐naphthalenyl)‐2‐vinylanthracene) homopolymer and its highly soluble copolymers with styrene or 9‐vinylcarbazole

A new blue fluorescent monomer, 9,10‐di(1‐naphthalenyl)‐2‐vinylanthracene, was designed and synthesized in good yield. Its homopolymer poly(9,10‐di(1‐naphthalenyl)‐2‐vinylanthracene) (P(ADN)) and soluble conductive vinyl copolymers poly[(9,10‐di(1‐naphthalenyl)‐2‐vinylanthracene)‐co‐styrene] (P(ADN‐co‐S)) and poly[(9,10‐di(1‐naphthalenyl)‐2‐vinylanthracene)‐co‐(9‐vinylcarbazole)] (P(ADN‐co‐VK)) were synthesized using free radical solution polymerization. All the polymers showed high glass transition mid‐point temperatures (203 to 237 °C) and good thermal stabilities. The photoluminescence emission of the copolymers was similar to that of P(ADN) (with two maxima at 423 and 442 nm). The lifetimes of P(ADN‐co‐S) (6.82 to 7.91 ns) were all slightly less than that of P(ADN) (8.40 ns). The lifetime of P(ADN‐co‐VK) increased from 7.8 to 8.8 ns with an increase in VK content. The fluorescence quantum yields of P(ADN‐co‐S) showed an overall increasing tendency from 0.42 to 0.58. The quantum efficiencies of P(ADN‐co‐VK) decreased from 0.36 to 0.19 with an increase of VK fraction. With increasing S/VK content, the highest occupied molecular orbital of P(ADN‐co‐S)/P(ADN‐co‐VK) ranged from ?5.58 to ?5.73 eV, which was similar to that of P(ADN) (?5.71 eV). The band gaps of P(ADN‐co‐S) and P(ADN‐co‐VK) were about 2.97 eV, which were equal to that of P(ADN), and smaller than that of 2‐methyl‐9,10‐di(1‐naphthalenyl)anthracene (MADN) (3.04 eV) and poly(9‐vinylcarbazole) (3.54 eV). Preliminary electroluminescence results were obtained for a homojunction device with the configuration ITO/MoO₃ (20 nm)/P(ADN)/LiF (1 nm)/Al (100 nm), which achieved only 30–50 cd m^?2, due to P(ADN) having a low mobility of 4.7 × 10^?8 cm² V^?1 s^?1 compared to that of its model compound MADN of 6.5 × 10^?4 cm² V^?1 s^?1. © 2013 Society of Chemical Industry