Synthesis of well‐defined comb‐like graft (co)polymers by nucleophilic substitution reaction between living polymers and polyhalohydrocarbon

A series of graft (co)polymers were synthesized by nucleophilic substitution reaction between iodinated 1,2‐polybutadiene (PB‐I, backbone) and living polymer lithium (side chains). The coupling reaction between PB‐I and living polymers can finish within minutes at room temperature, and high conversion (up to 92%) could be obtained by effectively avoiding side reaction of dimerization when living polymers were capped with 1,1‐diphenylethylene. By virtue of living anionic polymerization, backbone length, side chain length, and side chain composition, as well as graft density, were well controlled. Tunable molecular weight of graft (co)polymers with narrow molecular weight distribution can be obtained by changing either the lengths of side chain and backbone, or the graft density. Graft copolymers could also be synthesized with side chains of multicomponent polymers, such as block polymer (polystyrene‐b‐polybutadiene) and even mixed polymers (polystyrene and polybutadiene) as hetero chains. Thus, based on living anionic polymerization, this work provides a facile way for modular synthesis of graft (co)polymers via nucleophilic substitution reaction between living polymers and polyhalohydrocarbon (PB‐I). © 2013 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2013     

Synthesis of novel diene polymer via friedel–crafts‐type reaction of polybutadiene with aromatic compounds

This study describes a novel and facile synthesis strategy for a styrene‐butadiene rubber (SBR)‐like polymer via Friedel–Crafts‐type reaction between aromatic compounds and polybutadiene using an aluminum chloride as a catalyst. Although gelation was induced by a reaction of a generated carbocation with olefins in other polybutadiene chains in benzene and toluene because of their low electron densities on their rings, anisole with a higher electron density reacted with the polybutadiene carbocation efficiently. The introduction ratio of anisole increased as the reaction proceeded, and the obtained polymer, BRAN polymer, contained 15% anisoles for olefins in the polybutadiene in 4 h at 80 °C as estimated by ¹H NMR analysis. The glass‐transition temperature (T_g) of the BRAN polymer also increased with anisole content (T_g ~?50 °C when anisole contents 20%). The vulcanizate containing the BRAN polymer showed higher mechanical properties compared to samples using other matrix polymers. © 2019 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2019 , 57, 841–847     

Hydrophobic coatings from photochemically prepared hydrophilic polymethacrylates via electrospraying

Linear poly(hydroxyethyl methacrylate‐co‐methyl methacrylate) P(HEMA‐co‐MMA) and poly(dimehylaminoethyl methacrylate‐co‐methyl methacrylate) P(DMAEMA‐co‐MMA) and their corresponding hyperbranched copolymers were synthesized by conventional photoinitiated free radical polymerization and self‐condensing vinyl polymerization (SCVP) using Type I and Type II photoinitiators, respectively. Then, the polymers were processed by electrospraying in N, N‐dimethylformamide. The surface of the resulting electrospray coatings was examined by SEM, XPS, and WCA then compared with those prepared by drop casting. Regardless of the structural nature of the polymers, electrospraying allows the preparation of rough surface that shows more hydrophobic behavior. Electrospray coatings with linear and hyperbranched copolymers exhibited WCA as ～150° and ～130°, respectively, indicating that branching reduces the WCA. © 2016 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017 , 55, 1338–1344     

Synthesis and optoelectronic properties of alternating benzofuran/terfluorene copolymer with stable blue emission

The solution processable alternating benzofuran/terfluorene copolymer bearing side oxadiazole groups ( PBF‐OXD ) was synthesized and its optoelectronic properties and color stability were investigated. Electron‐deficient and stereohindered oxadiazole units were used as pendent groups to compensate for the poor electron‐transporting ability of a p‐type polymer backbone, to depress the intermolecular π‐stacking, and to improve solubility while retaining polymer blue emission. PBF‐OXD showed a glass transition at 135 °C and an onset decomposition temperature of ～345 °C. A simple EL device, with the configuration of ITO/PEDOT:PSS/ PBF‐OXD /Ba/Al, displayed a stable blue emission (λ_max = 434 nm), good color purity (full width half‐maximum = 59 nm), maximum brightness of 1400 cd/m², and a maximum luminance efficiency of 0.95 cd/A. The PL and EL spectra changed slightly on annealing and on increasing the applied voltage. These results show that the as‐synthesized copolymer PBF‐OXD had integrated respective functions of its different building blocks and exhibited good thermal and color stability with improved EL performance. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 5488–5497, 2009     

Synthesis and self‐assembly of amphiphilic dendronized conjugated polymers

Two kinds of amphiphilic dendronized conjugated polymers, polyfluorene (PF) and poly(binaphthyl‐alt‐fluorene) (PBF), were synthesized by Suzuki polycondensation of hydrophobic macromonomers with two nonpolar octyloxy chains and hydrophilic macromonomers with two polar oligo(ethylene oxide) chains. In these polymers, PF possesses a linear rod‐like backbone structure, and PBF adopts a folded rigid backbone structure. The different configurations in the conjugated main chains result in different supramolecular self‐assembly morphologies. The optical and thermal properties of PF and PBF were also studied. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 574–584, 2008     

CNT templated regioselective enzymatic polymerization of phenol in water and modification of surface of MWNT thereby

Carbon nanotubes (CNTs) are used as templates to synthesize regioselective polymers from enzymatic polymerization of phenol in water. About 90% of total polymeric units in the obtained polymers are the highly thermally stable oxyphenylene units. The polymer‐yields are dependent on the quantities of CNTs used. On the basis of MWNT‐templated enzymatic polymerization of phenol, covalent attachment of polyphenol chains to the surface of MWNT by way of a linking molecule, hydroquinone, is achieved. This approach supplies a novel way for producing high‐performance polymers and for functionalization of the surface of CNT. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 1627–1635, 2009     

Synthesis of low polydispersity polybutadiene and polyethylene stars by convergent living anionic polymerization

Star‐shaped polybutadiene stars were synthesized by a convergent coupling of polybutadienyllithium with 4‐(chlorodimethylsilyl)styrene (CDMSS). CDMSS was added slowly and continuously to the living anionic chains until a stoichiometric equivalent was reached. Gel permeation chromatography‐multi‐angle laser light scattering (GPC‐MALLS) was used to determine the molecular weights and molecular weight distribution of the polybutadiene polymers. The number of arms incorporated into the star depended on the molecular weight of the initial chains and the rate of addition of the CDMSS. Low molecular weight polybutadiene arms (M_n = 640 g/mol) resulted in polybutadiene star polymers with an average of 12.6 arms, while higher molecular weight polybutadiene arms (M_n = 16,000 g/mol) resulted in polybutadiene star polymers with an average of 5.3 arms. The polybutadiene star polymers exhibited high 1,4‐polybutadiene microstructure (88.3–93.1%), and narrow molecular weight distributions (M_w/M_n = 1.11–1.20). Polybutadiene stars were subsequently hydrogenated by two methods, heterogeneous catalysis (catalytic hydrogenation using Pd/CaCO₃) or reaction with p‐toluenesulfonhydrazide (TSH), to transform the polybutadiene stars into polyethylene stars. The hydrogenation of the polybutadiene stars was found to be close to quantitative by ¹H NMR and FTIR spectroscopy. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 828–836, 2006     

Glaser coupling of polymers: Side‐reaction in Huisgens “click” coupling reaction and opportunity for polymers with focal diacetylene units in combination with ATRP

Atom transfer radical polymerization (ATRP) was used in combination with Glaser type coupling, allowing the clean and efficient formation of symmetrically coupled polymers with a central diacetylene unit. The feasibility of the clean acetylene coupling was investigated with alkyne terminated poly(ethylene glycol) and poly(styrene) obtained by ATRP. The latter allowed subsequent ATRP to be carried out from the coupled products, offering opportunities for the formation of well defined functional materials with central diacetylene units. Glaser coupling was also observed as a side reaction in Huisgens‐type “click” reactions of polymeric alkynes with hindered surface azide groups. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 3795–3802, 2009     

Poly(methyl methacrylate)/silica nanocomposite fibers by electrospinning

Uniform poly(methyl methacrylate) (PMMA)/silica nanocomposite fibers containing up to 20 wt % silica were prepared by electrospinning. The electrospun solutions were prepared by mixing a solution of PMMA in dimethyl formamide (DMF) with colloidal silica in methyl ethyl ketone (MEK). The average fiber diameter decreases from 2.49 μm to 1.69 μm when 20 wt % silica is incorporated as a result of considerably increased solution conductivity, although the solution viscosity increases significantly, which should result in opposite effect. Thinner fibers (down to 350 nm) can be obtained by changing DMF/MEK proportion and by the addition of an ammonium salt. Nano‐sized silica particles (10–40 nm) distributes homogeneously in the fibers, as revealed by transmission electron microscopy. Furthermore, the incorporation of silica nanoparticles can change the thermal properties and surface wettability of the fiber mats. © 2009 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 47: 1211–1218, 2009     

Synthesis,characterization, and properties of polyurethanes containing 1,4:3,6‐dianhydro‐D‐sorbitol

Two‐ and three‐component polyurethanes containing 1,4:3,6‐dianhydro‐D ‐sorbitol (isosorbide) derived from glucose were synthesized using n‐BuSn(?O)OH·H₂O as a catalyst, and the thermal properties (T_g, T_d) of the polymers were investigated by differential scanning calorimetry and thermogravimetric analysis. We carried out molds for polyurethanes, the molds of polyurethanes were obtained. The dynamic mechanical analyzes showed that the storage modulus values of the three‐component polymers were constant to a higher temperature than those of the two‐component polymers. The storage moduli (E′), loss moduli (E″), and values of tan δ for the polymers were obtained. The rigidity of three‐component polymers was increased by the introduction of bisphenol A and diphenylmethane group to two‐component polymer. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 6025–6031, 2009     

Dielectric relaxations of chitosan: The effect of water on the α‐relaxation and the glass transition temperature

In this work thermal relaxations of chitosan are reported by using a novel methodology that includes subtraction of the dc conductivity contribution, the exclusion of contact and interfacial polarization effects, and obtaining a condition of minimum moisture content. When all these aspects are taken into account, two relaxations are clearly revealed in the low frequency side of the impedance data. We focus on the molecular motions in neutralized and non‐neutralized chitosan analyzed by dielectric spectroscopy in the temperature range from 25 to 250 °C. Low and high frequency relaxations were fitted with the Havriliak and Negami model in the 10^?1 to 108 Hz frequency range. For the first time, the low frequency α‐relaxation associated with the glass‐rubber transition has been detected by this technique in both chitosan forms for moisture contents in the range 0.05 to 3 wt % (ca. 18–62 °C). A strong plasticizing effect of water on this primary α‐relaxation is observed by dielectric spectroscopy and is supported by dynamic mechanical analysis measurements. In the absence of water (<0.05 wt %) the α‐relaxation is obscured in the 20–70 °C temperature range by a superposition of two low frequency relaxation processes. The activation energy for the σ‐relaxation is about 80.0–89.0 kJ/mol and for β‐relaxation is about 46.0–48.5 kJ/mol and those values are in agreement with that previously reported by other authors. The non‐neutralized chitosan possess higher ion mobility than the neutralized one as determined by the frequency location of the σ‐relaxation. © 2009 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 47: 2259–2271, 2009     

Mechanical properties of molecular composites. I. Poly (p‐phenylene terephthalamide) anion molecules dispersed in poly(4‐vinylpyridine)

Molecular composites have been prepared by dispersing rigid‐rod molecules of ionically‐modified poly(p‐phenylene terephthalamide) (PPTA anion) in a polar poly(4‐vinylpyridine) (PVP) matrix. For concentrations up to 5 wt % of the rigid‐rod reinforcement, the resulting composites are transparent and possess a single glass transition temperature that increases with concentration of the PPTA anion. The mechanical properties of the molecular composites are found to increase with concentration and to attain maximum values at about 5 wt % of the PPTA anion. The enhancement in properties, and the miscibility induced between the two component polymers, is attributed to the development of specific interactions between the ionic groups of the PPTA anion and the polar units of the PVP matrix. When such interactions are not present, as in composites reinforced with non‐ionic PPTA, the samples are opaque and their properties are significantly reduced compared to those of the PPTA anion/PVP composites. © 1999 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 37: 2201–2209, 1999     

Liquid crystalline conjugated polymers and their applications in organic electronics

This article describes the syntheses and electro‐optical applications of liquid crystalline (LC) conjugated polymers, for example, poly(p‐phenylenevinylene), polyfluorene, polythiophene, and other conjugated polymers. The polymerization involves several mechanisms: the Gilch route, Heck coupling, or Knoevenagel condensation for poly(p‐phenylenevinylene)s, the Suzuki‐ or Yamamoto‐coupling reaction for polyfluorenes, and miscellaneous coupling reactions for other conjugated polymers. These LC conjugated polymers are classified into two types: conjugated main chain polymers with long alkyl side chains, namely main‐chain type LC polymers, and conjugated polymers grafting with mesogenic side groups, namely side‐chain type LC conjugated polymers. In general, the former shows higher transition temperature and only nematic phase; the latter possesses lower transition temperature and more mesophases, for example, smectic and nematic phases, depending on the structure of mesogenic side chains. The fully conjugated main chain promises them as good candidates for polarized electroluminescent or field‐effect devices. The polarized emission can be obtained by surface rubbing or thermal annealing in liquid crystalline phase, with maximum dichroic ratio more than 20. In addition, conjugated oligomers with LC properties are also included and discussed in this article. Several oligo‐fluorene derivatives show outstanding polarized emission properties and potential use in LCD backlight application. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 2713–2733, 2009     

Miscibility and surface segregation in PVC/polyester blends—The influence of chain architecture and composition

Four poly(butylene adipate) (PBA) polyesters, the structure ranging from linear to highly branched, were synthesized and solution casted with poly(vinyl chloride) (PVC) in 20 or 40 wt % concentrations to evaluate the influence of polyester chain architecture on miscibility, surface segregation, and mechanical properties. The miscibility of PVC and polyesters is based on specific interactions between the carbonyl group in the polyester and PVC. These interactions cause a shift in the carbonyl absorption band in the FTIR spectra. The shifting of the carbonyl absorption band was more significant for all the 40 wt % blends compared with the blends containing 20 wt % of the same polyester. In the 20 wt % blends surface segregation and enrichment of polyester at the blend surface increased as a function of branching. However, all the films containing 40 wt % of polyester had similar surface composition. This is explained by better miscibility and stronger intermolecular interactions in the 40 wt % blends, which counteract the effect of branching on the surface segregation. High degree of branching resulted in poor miscibility with PVC and poor mechanical properties. A linear or slightly branched polyester structure, however, resulted in good miscibility and desirable blend properties. © 2007 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 45: 1552–1563, 2007     

New aromatic benzazole polymers. I. Benzobisthiazole and benzobisoxazole polymers with main-chain triarylamino units

Thermally stable, nonrigid-rod poly(benzobisthiazoles), (R)TPA-PBZT , where R = H, Me, NMe₂, and OH, and poly(benzobisoxazoles), (R)TPA-PBO , where R = Me, NMe₂ containing electron-rich triarylamine groups with various para-substituents (Rs) on the pendent phenyl ring, were synthesized from either 2,5-diamino-1,4-benzenedithiol dihydrochloride or 2,4-diamino-1,5-benzenediol dihydrochloride and the respective triarylamine-based dinitrile or diacid monomer in polyphosphoric acid. Whereas (R)TPA-PBZT polymers were obtained in moderate molecular weights, analogous (R)TPA-PBO polymers were only prepared in low molecular weights. No lyotropic behaviors, characteristic of the unmodified rigid-rod benzazole polymers, as evidenced by the absence of either stir opalescence or birefringence under crosspolarizers, were observed for these homopolymers at about 10 wt % polymer concentration. Among these polymers, only (Me)TPA-PBZT and (NMe₂)TPA-PBZT formed cast films with good mechanical integrity. In their pristine state, their film conductivity values were in the range of 10⁻¹⁰–10⁻⁹ S/cm at room temperature. Upon exposure to iodine vapor, their conductivities were increased to the maximal values of 5.0 × 10⁻⁵ S/cm ( (Me)TPA-PBZT ) and 4.1 × 10⁻⁴ S/cm ( (NMe₂)TPA-PBZT ). © 1997 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 35 : 1909–1924, 1997     

Tough interconnected polymerized medium and high internal phase emulsions reinforced by silica particles

Emulsion templating using high internal phase emulsions is an effective route to prepare low density and high porosity macroporous polymers known as polymerized high internal phase emulsions (polyHIPEs). Conventional polyHIPEs, synthesized from surfactant stabilized w/o emulsions have low permeabilities and poor mechanical properties. We present interconnected open macroporous low density nanocomposites produced by polymerizing the continuous phase of emulsion templates, which contained styrene, polyethyleneglycoldimethacrylate, and silylated silica particles. Polyethyleneglycoldimethacrylate and the silylated silica particles acted as crosslinker. The functionalized silica particles were incorporated into the polymer, which resulted in a significant improvement of the mechanical properties of the polyHIPEs without affecting the interconnected and permeable pore structures. The polyHIPEs contained up to 60 wt % silylated silica particles. Young's modulus of the reinforced macroporous polymers increased up to 600% compared with nonreinforced macroporous polymers. The mechanical performance was further increased by increasing the foam density of the macroporous nanocomposites from around 200 to 370 g/cm³ by raising the organic phase volume of the emulsion templates from 20 to 40 vol %. The macroporous polymers synthesized from less concentrated emulsions also possessed interconnected open porous although less permeable structures. The polyHIPE nanocomposites have a permeability of about 200 mD, whereas the polyMIPE nanocomposites still have permeabilities of around 50 mD. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 1979–1989, 2010     

Synthesis of Boltorn 1,2,3‐triazole dendrimers by click chemistry

Second‐, third‐, and fourth‐generation hyperbranched aliphatic polyols namely Boltorn® H20, Boltorn H30, and Boltorn H40 were endcapped with azido and activated acetylenic groups in good to excellent yields (75–95%) following an acid catalyzed procedure. The resultant terminally functionalized dendritic azido and acetylenic groups undergo 1,3‐dipolar cycloaddition using methyl (or ethyl) propiolate and benzyl azide, respectively, under catalytic or noncatalytic conditions below 40 °C to yield 1,2,3‐triazole dendrimeric polymers in 82–95% yield, under extremely mild conditions that could be applied for compounds sensitive to acid, base, or heat. The dendritic azido and activated acetylenic derivatives may act as novel scaffolds to tune the mechanical properties of different polymers. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 3748–3756, 2009     

Synthesis and characterization of polypropylene-graft-poly(l-lactide) copolymers by CuAAC click chemistry

The syntheses of polypropylene-graft-poly(l -lactide) copolymers (PP-g-PLAs) via copper (I)-catalyzed azide-alkyne cycloaddition “click” reaction (CuAAC) using azide side-chain functionalized polypropylene (PP-N₃) and alkyne end-functionalized poly(l -lactide) (PLA-Alkyne) were reported. The CuAAC was then applied to azide and different feeding ratios of alkyne functional polymers to give PP-g-PLAs that were characterized by FTIR, ¹H-NMR, GPC, DSC, and WCA measurements. The CuAAC click reaction was achieved by two different feeding ratio (PP-N₃:PLA-Alkyne = 1:5 and 1:10) and thermal, biodegradable, and surface properties of obtained graft copolymers were investigated. The molar ratio of PLA were calculated as 72.7 (PP-g-PLA-1) and 78.4% (PP-g-PLA-2) by ¹H-NMR spectroscopy. The water contact angle (WCA) values of PP-g-PLA-1 (81^o ± 1.3) and PP-g-PLA-2 (75^o ± 1.6) copolymers were compared with commercial chlorinated polypropylene (PP-Cl) (90^o ± 1.0), suggesting a more hydrophilic nature of desired graft copolymers produced. Conversely, the enzymatic biodegradation studies revealed that the weight losses of graft copolymers were determined as 13.6 and 22.1%, which is about 4% for commercial PP-Cl sample. Thus, it was clear that this simple and facile method was effective in promoting biodegradation of commercial polypropylene and attractive particularly for worldwide environmental remediation goals. © 2018 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2018 , 56, 2595–2601     

Modification of RAFT‐polymers via thiol‐ene reactions: A general route to functional polymers and new architectures

An investigation into the aminolysis of ω‐end groups of RAFT‐polymers and simultaneous thiol‐ene reactions with ene‐bearing compounds is described. Three different polymers, P(MMA), P(HPMA), and P(NIPAAm), with low PDIs were synthesized using dithiobenzoate and trithiocarbonate RAFT agents. P(NIPAAm) synthesized with trithiocarbonate RAFT agent and P(HPMA) synthesized with dithiobenzoate RAFT agent were both functionalized with a methacrylate‐modified mannose and a maleimide‐modified biotin via one‐pot simultaneous aminolysis and thiol‐ene reactions with product yields above 85%. The presence of ene‐compounds during aminolysis was shown to prevent the formation of disulfide interchain crosslinking. Using the same approach, P(MMA), P(HPMA), and P(NIPAAm) were converted to (meth)acrylate macromonomers with high yields (>80%). In the case of P(MMA), the simultaneous aminolysis and thiol‐ene addition prevented any intrachain side reactions, i.e., thiolactone formation. New architectures such as graft and block copolymers were successfully generated from the macromonomers. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 3773–3794, 2009     

Highly sulfonated multiblock copoly(ether sulfone)s for fuel cell membranes

Highly sulfonated multiblock copoly(ether sulfone)s applicable to proton electrolyte fuel cells (PEFCs) were synthesized by the coupling reaction of corresponding hydroxyl‐ terminated oligomers in the presence of highly reactive decafluorobiphenyl (DFB) as a chain extender, followed by postsulfonation with concentrated sulfuric acid. Their molecular weights were reasonably high as determined by viscosity measurement (η_inh = 0.72–1.58 dL/g). It was also confirmed that postsulfonation selectively took place in hydrophilic segments to yield highly sulfonated multiblock copolymers (IEC = 1.90–2.75 mequiv/g). The resulting polymers gave transparent, flexible, and tough membranes by solution casting. The 4b membrane, as a representative sample, demonstrated good mechanical strength in the dry state regardless of high IEC value (2.75 mequiv/g). The 4a–c membranes with higher IEC values (IEC = 2.75–2.79 mequiv/g) maintained high water uptake (13.7–17.7 wt %) at 50% RH and it was still high (7.4–8.5 wt %) at 30% RH. Proton conductivity of all membranes at 80 °C and 95% RH was higher than that of Nafion 117. Furthermore, the 4a membrane showed high proton conductivity, comparable with Nafion 117 in the range of 50–95% RH, and maintained high proton conductivity (2.3 × 10^?3 S/cm) even at 30% RH. Finally, the surface morphology of the membrane was investigated by tapping mode atomic force microscopy, which showed well‐connected hydrophilic domains that could work as proton transportation channel. This phase separation and the high water uptake behavior probably contributed to high and effective proton conduction in a wide range of relative humidity. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 2757–2764, 2010