Construction of excellent thermal latent system for the synthesis of networked epoxide polymers by sulfonium salts

An efficient thermally latent initiation system using dual sulfonium salts, consisting S‐benzylsulfonium salt 1 bearing counter anion and S,S‐dimethylsulfonium salt 2 bearing CH₃ counter anion, has been developed for the cationic polymerization of epoxides. Compared to the conventional system using 1 as a thermally latent initiator, the newly developed system allowed significant improvement of stability of epoxy formulations during storage at ambient temperature without sacrificing their curability at elevated temperatures. Such a remarkable performance is attributable to the nucleophilic attack of CH₃ to cationic species formed unavoidably by the reaction of 1 with epoxide. Such entrapment of cationic species into the corresponding dormant led to the inhibition of undesirable chain growth of polymers during storage of epoxy formulations. In addition, the dormant can undergo dissociation at elevated temperature to give cationic species, which can readily initiate the polymerization of epoxide. © 2018 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2018 , 56, 2096–2102     

Synthesis of gradient copolysiloxanes by simultaneous copolymerization of cyclotrisiloxanes and mechanism for kinetics inverse between anionic and cationic ring‐opening polymerization

Trifluoropropylmethylsiloxane–phenylmethylsiloxane gradient copolysiloxanes were synthesized by anionic and cationic ring‐opening polymerization (ROP) of 1,3,5‐tris(trifluoropropylmethyl)cyclotrisiloxane ( ) and phenylmethylcyclotrisiloxane ( ). The analysis of reactivity ratios revealed that the reactivity of toward anionic ROP was higher than that of ; however, exhibited lower reactivity compared with during the cationic ROP. AB and BAB type gradient copolymers were obtained because of a difference in the reactivity of the monomers. The microstructure of copolymers was characterized by ²⁹Si NMR spectroscopy, gel permeation chromatography, and differential scanning calorimetry. Furthermore, the mechanism for kinetics inverse of copolymerization was proposed based on the results of the optimized molecular configuration. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2016 , 54, 835–843     

Using controlled radical polymerization to confirm the lower critical solution temperature of an N‐(alkoxyalkyl) acrylamide polymer in aqueous solution

N‐(3‐Methoxypropyl) acrylamide (MPAM) was polymerized by controlled radical polymerization (CRP) methods such as nitroxide‐mediated polymerization (NMP) and reversible addition–fragmentation chain‐transfer polymerization (RAFT). CRP was expected to yield well‐defined polymers with sharp lower critical solution temperature (LCST) transitions. NMP with the BlocBuilder (2‐([tert‐butyl[1‐(diethoxyphosphoryl)‐2,2‐dimethylpropyl]amino]oxy)‐2‐methylpropanoic acid) and SG1 ([tert‐butyl[1‐(diethoxyphosphoryl)‐2,2‐dimethylpropyl]amino] oxidanyl) initiating system revealed low yields and lack of control (high dispersity, ? ～ 1.5–1.6, and inhibition of chain growth). However, RAFT was far more effective, with linear number average molecular weight, , versus conversion, X, plots, low ? ～ 1.2–1.4 and the ability to form block copolymers using N,N‐diethylacrylamide (DEAAM) as the second monomer. Poly(MPAM) (with = 13.7–25.3 kg mol^?1) thermoresponsive behavior in aqueous media revealed cloud point temperatures (CPT)s between 73 and 92 °C depending on solution concentration (ranging from 1 to 3 wt %). The and the molecular weight distribution were the key factors determining the CPT and the sharpness of the response, respectively. Poly(MPAM)‐b‐poly(DEAAM) block copolymer ( = 22.3 kg mol^?1, ? = 1.41, molar composition F_DEAAM = 0.38) revealed dual LCSTs with both segments revealing distinctive CPTs (at 75 and 37 °C for poly(MPAM) and poly(DEAAM) blocks, respectively) by both UV–Vis and dynamic light scattering. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2015 , 53, 59–67     

Synthesis and properties of long‐chain branched poly(ether sulfone)s by self‐polycondensation of AB2 type macromonomers

Long‐chain branched poly(ether sulfone)s (PESs) were synthesized via self‐polycondensation of AB₂ macromonomers. The linear PES oligomers synthesized by self‐polycondensation of 4‐chloro‐4′‐(4‐hydroxyphenyloxy)diphenyl sulfone were terminated with 4‐(3,5‐methoxyphenoxy)‐4′‐fluorodiphenyl sulfone to form AB₂ macromonomer precursors. After conversion from methoxy to hydroxy groups, the AB₂ macromonomers were self‐polycondensed to form long‐chain branched PESs. NMR measurements support the formation of the target macromonomers ( = 2930–67,800 (g mol^?1); M_n = number average molecular weight) and long‐chain branched PESs. Gel permeation chromatography with multiangle light scattering measurements indicated the formation of high‐molecular‐weight (M_w) polymers over 10⁴. The root‐mean‐square radius of gyration (R_g) suggests that the shape of the long‐chain branched PES synthesized from small AB₂ macromonomers in solution is similar to that of hyperbranched polymers. Increasing resulted in larger R_g, suggesting a transition from hyperbranched to a linear‐like architecture in the resulting long‐chain branched PESs. Rheological measurements suggested the presence of strongly entangled chains in the long‐chain branched PES. Higher tensile modulus and smaller elongation at the break were observed in the tensile tests of the long‐chain branched PESs. It is assumed that the enhanced molecular entanglement points may act as physical crosslinks at room temperature. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014 , 52, 1825–1831     

Facile synthesis of Au@PNIPAM‐b‐PPy nanocomposites with thermosensitive and photothermal effects

In this article, we reported a facile method to in‐situ synthesize Au@PNIPAM‐b‐PPy nanocomposites with thermosensitive and photothermal effects using amphiphilic poly(N‐isopropylacrylamide)‐block‐poly(pyrrolylmethylstyrene) (PNIPAM‐b‐PPMS) diblock copolymers as ligands. The hydrophobic PPMS block can in‐situ reduce to zero‐valent gold and simultaneously be oxidatively copolymerized with the free pyrrole monomers to form a crosslinked and conjugated polypyrrole (PPy) layer. The hydrophilic PNIPAM block as a stabilizer can produce highly thermosensitive effect. Moreover, the resultant Au@PNIPAM‐b‐PPy nanomaterials show a strong absorption in the near infrared (NIR) region, which endowed the system excellent photothermal effect. On the basis of the PPy photothermal and PNIPAM thermosensitive effects, the above Au@PNIPAM‐b‐PPy nanomaterials show a reversible, soluble‐precipitate transition upon the NIR irradiation off‐on. © 2016 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2016 , 54, 3079–3085     

Amphiphilic β‐cyclodextrin‐based star‐like block copolymer unimolecular micelles for facile in situ preparation of gold nanoparticles

Multifunctional polymer unimolecular micelles, which are used as templates to fabricate stable gold nanoparticles (GNPs) in one‐step without external reductant, have been designed and prepared. Amphiphilic 21‐arm star‐like block copolymers β‐cyclodextrin‐{poly(lactide)‐poly(2‐(dimethylamino) ethyl methacrylate)‐poly[oligo(2‐ethyl‐2‐oxazoline)methacrylate]}₂₁ [β‐CD‐(PLA‐PDMAEMA‐PEtOxMA)₂₁] and the precursors are synthesized by the combination of ring‐opening polymerization (ROP) and activators regenerated by electron transfer atom transfer radical polymerization (ARGET ATRP). The tertiary amine groups of PDMAEMA block reduce the counterion to zerovalent gold in situ, and these gold atoms combine mutually to form final GNPs. GNPs with relatively small size and narrow size distribution can be obtained in longer DMAEMA block copolymer, larger molar ratio of DMAEMA to HAuCl₄ and smaller absolute concentrations of both polymer and HAuCl₄. These results showed that the unimolecular micelles can be used as templates for preparing and stabilizing GNPs in situ without any external reducing agents and organic solvents, suggesting that the nanocomposite systems are latent nanocarriers for further biomedical application. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2016 , 54, 186–196     

Synthesis,thermal analysis,and linear and nonlinear optical characterization of substituted polyphosphonates derived from 1,12‐dodecanediol

The syntheses of a series of substituted polyphosphonates of the type [OP(X)(Ar)O(CH₂)₁₂]_n (X = O, S, Se; Ar = phenyl, 2,2′‐bithienyl‐5‐yl) are reported. The s for the polyphosphonates range from 1.1 to 4.6 × 10⁴ Da and are significantly higher than those previously reported for polyphosphonates synthesized via polycondensation reactions. Thermal characterization indicates that all of the polymers are in the rubbery state at room temperature and have thermal stabilities as high as 290 °C. The linear absorption spectra, emission spectra, and emission quantum yields of the 2,2′‐bithenyl‐5‐yl substituted polyphosphonates show distinct trends with respect to the chalcogen attached to the phosphorus. Solutions of these polymers show emission at wavelengths ranging from 380 to 400 nm and, depending on the choice of X, the quantum yields are considerably larger than that of 2,2′‐bithiophene. Nonlinear optical measurements of the polyphosphonates with 2,2′‐bithenyl‐5‐yl substituents show that nonlinear absorbance increases with increasing molecular weight of X. © 2016 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2016 , 54, 3663–3674     

On the origin and consequences of high DMAEMA reactivity ratio in ATRP copolymerization with MMA: An experimental and theoretical study#

Designing and tuning a copolymerization process to obtain specific material properties is still fundamentally empirical and requires the determination of apparent reactivity ratios r^s. To this end, PEG–(MMA–DMAEMA)_n copolymers obtained via ATRP of MMA and DMAEMA using a PEG‐based initiator in toluene were analyzed to extract monomer relative reactivities; the impact of changing solvent on the latter was also tested. Differing from previous free radical and controlled radical copolymerizations (CRcoP), we found that DMAEMA is preferentially included ( and ) in toluene; increasing the solvent polarity decreased the gap between r^s. With these data, kMC simulations based on the copolymerization terminal model were used to investigate copolymer microstructure, which is not amenable to NMR investigation. kMC simulations evidenced both a gradient‐like nature of the copolymers and a somewhat unexpected qualitative change in the probability of finding MMA‐rich triads along the chain depending on initial feed composition. An additional DFT analysis suggested the likely formation of a DMAEMA:CuBr:2‐2′‐bipyridine complex, which being involved in the regeneration of reactive radicals from dormant species, is expected to locally increase DMAEMA concentration favoring its addition to the growing chains. The formation of such complex is also supported by ¹H‐NMR experiments. © 2018 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2018 , 56, 1366–1382     

Heterofunctional RAFT‐derived PNIPAM via cascade trithiocarbonate removal and thiol‐yne coupling click reaction

An efficient one‐pot process to functionalize the α‐ and ω‐positions of RAFT‐derived poly(N‐isopropylacrylamide) (PNIPAM) by two inherently different mechanistic pathways is reported. The method relies on the RAFT polymerization of NIPAM using a new alkyne‐based RAFT agent, namely 2‐cyano‐5‐oxo‐5‐(prop‐2‐yn‐1‐ylamino)pentan‐2‐yl dodecyltrithiocarbonate (COPYDC) and the combination of thiol‐yne click chemistry and thiocarbonylthio chain‐end removal reactions. COPYDC was prepared in good yield and used as an efficient chain transfer agent during the RAFT polymerization of NIPAM. Well‐defined polymers with controlled molar masses ( = 7500–14,700 g.mol^?1) and narrow dispersities (? = 1.18–1.26) are thus obtained. Cascade thiol‐yne click reaction at the alkyne α‐chain end and trithiocarbonate removal at the ω‐chain end are successfully achieved using benzyl mercaptan and excess AIBN. The reported method provides a facile and mild route to heterofunctional telechelic RAFT polymers with predictable molar masses and low dispersities. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017 , 55 , 3597–3606     

Cationic ring‐opening polymerization of trimethylene carbonate to α,ω‐dihydroxy telechelic and star‐shaped polycarbonates catalyzed by reusable o‐benzenedisulfonimide

Cationic ring‐opening polymerization of trimethylene carbonate using o‐benzenedisulfonimide as a reusable catalyst under mild conditions was described. The polymerization proceeded homogeneously without decarboxylation and poly(trimethylene carbonates) (PTMCs) were synthesized with well‐controlled molecular weights and narrow polydispersities (M_w/M_n = 1.12–1.18). The spectra of ¹H‐NMR, SEC, and MALDI–ToF MS clearly demonstrated the incorporation of the initiator residue into the polymer chains and the controlled/living nature of the polymerizations. Furthermore, the catalyst can be easily recovered, and its efficiency was fully retained. In addition, 1,3‐propanediol, 1,1,1‐trimethylolpropane, and pentaerythritol were successfully used as initiators to produce telechelic and star‐shaped polycarbonates which were determined by intrinsic viscosity experiments. The number of arms estimated by the shrinking factors ( ) were 2.0, 2.6, and 3.5, respectively, indicating the successful syntheses of the two‐, three‐, and four‐armed PTMCs. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2015 , 53, 729–736     

Novel pendent thiophene side‐chained benzodithiophene for polymer solar cells

In this article, pendent thiophene (2‐butyl‐5‐octylthiophene) side chain is used to modify the backbone of the polymers containing benzo[1,2‐b:4,5‐b′]dithiophene (BDT) and thieno[3,4‐c]pyrrole‐4,6‐dione (TPD). Compared with the dodecyloxy side‐chained polymer (P1), pendent thiophene‐based polymers (P2 and P3) show similar number‐average molecular weight (M_n), polydispersity index, thermal stability (T_d ～ 334–337 °C), and optical band gaps ( ) (～1.8 eV). Polymer (P2)‐based BDT with pendent thiophene and ethylhexyl‐modified TPD shows relatively low‐lying HOMO energy level (?5.52 eV) and nearly 1 V high open circuit voltage (V_OC). The polymer solar cell devices based on three copolymers show power conversion efficiencies from 2.01% to 4.13%. The hole mobility of these polymers tested by space charge limited current method range from 3.4 × 10^?4 to 9.2 × 10^?4 cm²V^?1s^?1. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2015 , 53, 1558–1566     

Preparation and orthogonal postmodification of dual‐clickable polymer precursors bearing both aldehyde and alkyne groups

A new styrenic monomer 2‐propargyloxy‐5‐vinylbenzaldehyde (PVB) containing both aldehyde and alkyne reactive groups was designed for the synthesis and subsequent orthogonal postfunctionalization of dual‐clickable polymer precursor. Reversible addition‐fragmentation chain transfer polymerization of PVB afforded a structurally well‐defined polymer poly(2‐propargyloxy‐5‐vinylbenzaldehyde) (PPVB) bearing alkyne and aldehyde functionalities that are reactive towards azide ‐ and aminooxy‐containing molecules, respectively. Therefore, the resulting PPVB can be served as a dual‐clickable polymer scaffold for construction of multiple functional polymers via orthogonal alkyne–azide and aldehyde–aminooxy click reactions. Postpolymerization modification of PPVB sequentially with aminooxy‐terminated poly(ethylene oxide)s (H₂NO‐PEO) and azide‐functionalized imidazolium‐type ionic liquid (N₃‐IL·TFSI, having bis(trifluoromethane)sulfonamide, TFSI, counter‐anion) yielded an interesting multicomponent graft polymer PPVB‐g‐(PEO‐and‐IL·TFSI). After anion exchange of hydrophobic TFSI counter‐anion by bromide (Br) anion, the resulting graft copolymer PPVB‐g‐(PEO‐and‐IL·Br) becomes soluble in water, and its imidazolium units can capture negatively charged tetraphenylethylene disulfonate derivative (TPE‐2 ) guest molecule via electrostatic complexation to form in situ self‐assembled fluorescent nanoaggregates with colloidal stability imparted by hydrophilic PEO chains. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017 , 55, 2650–2656     

Cationic polymerization of vinyl ethers with alkyl or ionic side groups in ionic liquids

Controlled cationic polymerization of isobutyl vinyl ether was demonstrated to proceed in an ionic liquid (IL), 1‐butyl‐3‐octylimidazolium bis(trifluoromethanesulfonyl)imide, using a 1‐(isobutoxy)ethyl acetate/TiCl₄ initiating system, ethyl acetate as an added base, and 2,6‐di‐tert‐butylpyridine as a proton trap reagent. Judicious choices of metal halide catalysts, counteranions of ILs, and additives were essential for controlling the polymerization. The polymerization proceeded much faster in the IL than in CH₂Cl₂, indicating an increased population of ionic active species in the IL due to the high polarity. Polymers with a relatively narrow molecular weight distribution were obtained in the IL with a bis(trifluoromethanesulfonyl)imide ( ) anion even in the absence of an added base, which suggested possible interactions of the counteranion of the IL with the growing carbocations. Moreover, the direct cationic polymerization of a vinyl ether with pendant imidazolium salts, 1‐(2‐vinyloxyethyl)‐3‐methylimidazolium bis(trifluoromethanesulfonyl)imide, proceeded in a homogeneous state in 1‐methyl‐3‐octylimidazolium bis(trifluoromethanesulfonyl)imide. The solubilities of the obtained polymers were readily tuned by counteranion exchange. © 2016 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2016 , 54, 1774–1784     

Synthesis of polymerizable poly(alkenoic acid)s via reversible addition fragmentation transfer polymerization for dental applications

The novel polymerizable poly(alkenoic acid)s 1a–1c (expected = 2500, 5000, and 10,000 g/mol) were synthesized in three steps starting from tert‐butyl acrylate. A RAFT polymerization using 2,2‐(thiocarbonylbis(sulfanediyl))bis(2‐methylpropanoic acid) 4 as a chain transfer agent, followed by a Mitsunobu esterification and a deprotection of the tert‐butyl ester groups with trifluoroacetic acid, provided the desired acidic polymers in moderate to good yields. The synthesized polymers were characterized by ¹H NMR spectroscopy and by gel permeation chromatography. The number‐average molecular weights measured for 1a–1c were in good agreement with the expected values. Self‐etch adhesives (SEAs) based on poly(alkenoic acid)s 1a–1c were formulated in order to investigate their adhesive properties. The addition of 1a–1c to a SEA formulation containing 10‐methacryloyloxydecyl dihydrogen phosphate resulted in a strong increase of the shear bond strength (SBS) of a dimethacrylate‐based composite to dentin. No significant influence of the polymer molecular weight on the dentin and enamel SBS was observed. © 2016 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2016 , 54, 1814–1821     

Enzyme and pH dual responsive l‐amino acid based biodegradable polymer nanocarrier for multidrug delivery to cancer cells

We report a new pH and enzyme dual responsive biodegradable polymer nanocarrier to deliver multiple anticancer drugs at the intracellular compartment in cancer cells. Natural l ‐aspartic acid was converted into multifunctional monomer and polymerized to yield new classes of biodegradable aliphatic polyester in‐build with pH responsiveness. The transformation of side chain BOC urethanes into cationic in the acidic endosomal environment disassembled the polymers nanoparticles (pH trigger‐1). The biodegradation of aliphatic polyester backbone by esterase enzyme ruptured the nanoassemblies and released the drugs in the cytoplasm (trigger‐2). The polymer scaffolds were capable of delivering multiple drugs such as doxorubicin, topotecan, and curcumin (CUR). The cytotoxicity of the nascent and drug‐loaded nanoparticles were tested in cervical (HeLa) and breast (MCF‐7) cancer cell lines. The nascent polymer nanoscaffolds were found to be nontoxic to cells whereas their drug‐loaded nanoparticles exhibited excellent killing. Confocal microscopic images revealed that the drug‐loaded polymer nanoparticles were taken up by the cells and the dual degradation process delivered the drugs to nucleus and established the proof‐of‐concept. The present investigation opens up new platform for l ‐amino acid based polyester scaffolds, for the first time, in the intracellular drug delivery in cancer treatment. © 2016 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2016 , 54, 3279–3293     

Effect of tetra‐n‐butylammonium bromide salt on the cationic polymerization of dimethylketene and on the thermal properties of the obtained polyketones

The cationic polymerization of dimethylketene is achieved in dichloromethane at ?30 °C, using a stoichiometric mixture of aluminum bromide (AlBr₃) and tetra‐n‐butylammonium bromide (n‐Bu₄N⁺Br^?) as initiator. Characterizations by ¹H and ¹³C NMR show that the resulting polymers have a perfect polyketonic microstructure. Capillary viscosity, DSC, and SEC analysis show that for a constant monomer/initiator ratio, polymers synthesized in the presence of tetra‐n‐butylammonium bromide are more crystalline and have better properties than those produced only with AlBr₃. Melting temperatures, inherent viscosities and average molecular weights are systematically higher. A good linearity is observed between ln (inherent viscosity) versus ln for the system with n‐Bu₄N⁺Br^?, showing a good control of the molecular weight by the initial feed ratio. The effect of this compound suggests a reversible equilibrium between active and dormant species, which limits the transfer and/or termination reactions, and enables a better control of the cationic polymerization. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014 , 52, 1493–1499     

Minor amounts of glycerol improve the properties of polyisobutylene‐based polyurethane and its nanocomposites

The synthesis of primary hydroxyl‐telechelic polyisobutylene, HOCH₂‐PIB‐CH₂OH, often yields product the number average terminal functionality ( $f_{n,{\mathrm{CH}}_2\mathrm{OH}}$) of which is less than theoretical 2.0, typically $f_{n,{\mathrm{CH}}_2\mathrm{OH}}$ = 1.75–1.95. Polyurethane (PU) prepared with such low‐cost imperfect PIB‐diols, unsurprisingly, exhibit poor overall properties. Herein we report that mechanical, rheological, and thermal properties of polyisobutylene‐based polyurethane (PIB‐PU) and PIB‐PU reinforced with organically modified montmorillonite (OmMMT) prepared with PIB‐diol of $f_{n,{\mathrm{CH}}_2\mathrm{OH}}$ = 1.85 are significantly enhanced by glycerol. Specifically, we document that calculated minor amounts of glycerol substantially improves tensile strength, ultimate elongation, elastic modulus, toughness, rubbery plateau, flow temperature, creep, permanent set, rate of recovery after loading, and thermal properties of PIB‐PU and OmMMT‐reinforced PIB‐PU prepared with PIB‐diol of $f_{n,{\mathrm{CH}}_2\mathrm{OH}}$ = 1.85. The observations are summarized and discussed in terms of chemistry, micromorphology, and viscoelasticity. © 2019 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2019 , 57, 929–935     

Preparation and characterization of layer‐by‐layer self‐assembly membrane based on sulfonated polyetheretherketone and polyurethane for high‐temperature proton exchange membrane

A concept of preparing high‐temperature proton exchange membranes with layer‐by‐layer (LBL) self‐assembly technique was proposed and the sulfonated polyetheretherketone (SPEEK) and polyurethane (PU) with 200 LBL deposition cycles denoting (SPEEK/PU)₂₀₀ membrane was prepared in this research. Owing to the strong electrostatic interaction between ? group in SPEEK and ? C? N⁺ group in PU, (SPEEK/PU)₂₀₀ membrane with LBL self‐assembly structure showed a favorable structural stability. The phosphoric acid (PA)‐doped (SPEEK/PU)₂₀₀ membrane showed a higher proton conductivity relative to PA doped SPEEK/PU membrane by solution casting method (SPEEK/PU)₂₀₀/40%PA membrane possessed a proton conductivity value of 2.90 × 10^?2 S/cm at 150 °C under anhydrous conditions. The LBL self‐assembly structure provided a possibility to reduce the negative effect from polymer skeleton blocking charge carrier species even immobilizing protons. Moreover, the (SPEEK/PU)₂₀₀ membrane presented the particularly noteworthy mechanical property even with PA doping. The tensile stress values at break were 72.8 and 24.1 MPa, respectively, for (SPEEK/PU)₂₀₀ and (SPEEK/PU)₂₀₀/40%PA membrane at room temperature, which were obviously higher than the reported values of 15.9 and 2.81 MPa for SPEEK/PU and SPEEK/PU/60%PA membrane. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017 , 55 , 3446–3454     

Polyisobutylene containing covalently bound antioxidant moieties

Polyisobutylene (PIB) bearing covalently bound antioxidants is reported. TiCl₄‐catalyzed cleavage/alkylation reactions were conducted on poly(isobutylene‐co‐isoprene) (EXXON® Butyl 068; ${\overline{\mathrm{M}}}_{\mathrm{n}}$ = 3.37 × 10⁵ g/mol, (Ð) = 1.29, and 1.08 mol % isoprene) at ?70 °C in 60/40 hexane/dichloromethane in the presence of 2,6‐di‐tert‐butylphenol (DTP). Resulting PIB ${\overline{\mathrm{M}}}_{\mathrm{n}}$ s ranged from 30,000 to 85,300 g/mol and number average DTP functionalities (F_n) ranged from 4.3 to 12.0. ¹H NMR showed that 25%–40% of the DTP moieties underwent de‐tert‐butylation to form mono‐tert‐butyl phenol moieties. DTP‐functionalized and nonfunctionalized control PIBs were subjected to thermogravimetric analysis in nitrogen and in air. In nitrogen, commercial control PIBs (olefinic end groups) showed delayed onset of thermal degradation (T₁₀ = 380–381 °C) relative to both control PIBs produced by living polymerization (tert‐chloride end groups) and DTP‐functionalized PIBs (T₁₀'s all within the range of 366–370 °C). All PIBs showed lower degradation temperatures in air compared to nitrogen. Various control PIBs suffered 90% weight loss in air at temperatures ranging from 372 °C to 410 °C; DTP‐functionalized PIBs did not suffer 90% weight loss in air until 412–414 °C. Oxidative induction time analysis showed that all control PIBs suffered catastrophic degradation within 6 min, and most within 1 min, but DTP‐functionalized PIBs resisted degradation for >100 min. © 2019 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2019 , 57, 1836–1846     

Synthesis and fractionation of poly(phenylene methylene)

Poly(phenylene methylene) (PPM) was isolated in a broad range of molar masses by optimization of the catalytic polymerization of benzyl chloride with SnCl₄ or FeCl₃, followed by fractionation by Soxhlet extraction or phase separation in concentrated solutions in poor solvents. Low molar mass products were also obtained by quenching the reaction at moderate monomer conversions. Products with number average molar masses (M_n) ranging from 200 to 61,000 g mol⁻¹ were isolated, the latter being an order of magnitude above the previously reported values. DSC analysis of polymers of different molar masses revealed that the glass transition temperature follows the Flory‐Fox equation reaching a plateau value of 65 °C at a molar mass between 10,000 and 20,000 g mol⁻¹. The onset of decomposition temperature of higher molar mass products proceeds above 450 °C (maximum decomposition rate at 515 °C), according to TGA. Furthermore, the substitution pattern of PPM was discussed by study of chemical shifts of the methylene group by extensive NMR spectroscopy (¹H, ¹³C, DEPT, and HSQC) and by comparison with two mono‐substituted derivatives of PPM—poly(2,4,6‐trimethylphenylene methylene) and poly(2,3,5,6‐tetramethylphenylene methylene)—which were synthesized analogous to PPM. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2018 , 56, 309–318