Star-shaped poly(2,6-dimethyl-1,4-phenylene ether)

Summary The properties of star-shaped poly(2,6-dimethyl-1,4-phenylene ether) (PPE) as prepared by the redistribution of PPE and tyrosine-modified poly(propylene imine) dendrimers, are studied in solution and in 50/50 wt% blends with linear polystyrene. Star polymers with constant armlength but increasing number of arms show the same hydrodynamic volume as measured by Size Exclusion Chromatography (SEC), but decreasing hydrodynamic radius as measured by Dynamic Light Scattering (DLS). This is caused by the restricted mobility of the more densely packed chains at high numbers of arms, also leading to a decrease in intrinsic viscosities. These solution properties are also reflected in the miscibility behaviour in polymer blends. Star-shaped polymers with a high number of PPE arms (16,32 or 64 respectively) give inhomogeneous blends with linear polystyrene, in contrast to the miscible combination of linear polystyrene with linear PPE or starshaped polymers with a low number (4 or 8) of PPE arms.     

Synthesis and properties of novel poly(aryl ether ketone)s containing imide linkages in the main chains

A new monomer containing imide linkages, bis[4-(p-phenoxybenzoyl)-1,2-benzenedioyl]-N,N,N′,N′-4,4′-diaminodiphenyl ether (BPBDADPE), was prepared by the Friedel–Crafts reaction of bis(4-chloroformyl-1,2-benzenedioyl)-N,N,N′,N′-4,4′-diaminodiphenyl ether (BCBDADPE) with diphenyl ether (DPE). Novel poly(aryl ether ketone)s containing imide linkages in the main chains (PEK-I) were synthesized by electrophilic Friedel–Crafts solution copolycondensation of terephthaloyl chloride (TPC) with a mixture of DPE and BPBDADPE. The polymers were characterized by different physico-chemical techniques. The polymers with 10–40 mol% BPBDADPE are semicrystalline and had increased T _gs over commercially available poly(ether ether ketone) (PEEK) and poly(ether ketone ketone) (PEKK) (70/30) due to the incorporation of imide linkages in the main chains. The polymers IV and V with 30–40 mol% BPBDADPE had not only high T _gs of 182–183 °C, but also moderate T _ms of 341–343 °C, having good potential for melt processing and exhibited high thermal stability and good resistance to common organic solvents.     

Novel Ferrocene-Based Organometallic Poly(ether sulfone amide imide)s: Preparation, Characterization, and Properties

A new ferrocene-based diamine (ESAFDA) with built-in ether, sulfone, and amide groups was prepared via reaction of two synthetic precursors. Firstly, 1,1′-ferrocenedicarbonyl chloride was prepared from 1,1′-ferrocenedicarboxylic acid using oxalyl chloride. In another reaction, nucleophilic substitution reaction of 3-aminophenol with bis(4-chlorophenyl sulfone) was used for synthesis of 3,3′-(4,4′-sulfonyl bis(1,4-phenylene) bis (oxy)) dianiline (SBOD). Finally, the diamine was prepared via nucleophilic reaction of SBOD with 1,1′-ferrocenedicarbonyl chloride. The precursors and the diamine were characterized by conventional methods and the diamine was used for preparation of different ferrocene-based poly(ether sulfone amide imide)s through polycondensation with three different dianhydrides. The polymers were characterized by elemental analysis, FTIR and ¹H-NMR spectroscopy. Various properties of the polymers including inherent viscosity, molecular weight, solubility, thermal stability and behavior, flame-retardant nature, mechanical properties, and crystallinity were studied. Presence of ferrocene structure in companion to ether, sulfone, and amide units in the backbone of polyimides led to improved solubility of the polymers in polar aprotic solvents and enhanced thermal stability and flame-retardant character of polyimides.     

Molar mass determination of poly(octadecene-alt-maleic anhydride) copolymers by size exclusion chromatography and dilute solution viscometry

The number average molar mass M_n of poly(octadecene-alt-maleic anhydride) (PODMA) copolymers calculated from data obtained by size exclusion chromatography (SEC) using a polystyrene (PS) calibration was found to be inaccurate. The use of SEC combined with dilute solution viscometry enabled a method to be developed using an iterative approach, which does not require knowledge of the Mark-Houwink constants for PODMA samples. A new calibration curve was constructed as a plot of molar mass M_u for PODMA. True number-average molar masses M_n (true) calculated using the new calibration are approximately twice the apparent molar mass M_n (app) based on a PS calibration for higher molar mass samples (>10?000 g mol⁻¹).     

Characterization of branched polymers by size exclusion chromatography coupled with multiangle light scattering detector. I. Size exclusion chromatography elution behavior of branched polymers

The elution behavior of branched macromolecules during their separation by size exclusion chromatography (SEC) was studied. The elution behavior of branched polymers was investigated using samples of randomly branched polystyrene and star branched poly(benzyl methacrylate) of different levels of branching by means of a SEC chromatograph coupled with a multiangle light scattering detector. Abnormal SEC elution behavior was found to be typical for highly branched polymers. After a normal elution at small elution volumes the molar mass and root mean square radius of the eluting molecules increased with increasing elution volume. Several SEC experiments were carried out to find explanation for this effect and SEC separation was compared with the separation by thermal field flow fractionation. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 1588–1594, 2001     

Synthesis,characterization, and thermal stability of novel wholly para-oriented aromatic poly(ether-amide-hydrazide)s bearing pendant groups and their corresponding poly(ether-amide-1,3,4-oxadiazole)s

Four novel wholly para-oriented aromatic poly(ether-amide-hydrazide)s containing various pendant groups on their aromatic rings were synthesized from p-aminosalicylic acid hydrazide (PASH) with an equimolar amount of either 4,4′-(1,4-phenylenedioxy)dibenzoyl chloride (1a), 4,4′-(2,5-tolylenedioxy)dibenzoyl chloride (1b), 4,4′-(2-tert-butyl-1,4-phenylenedioxy)dibenzoyl chloride (1c), or 4,4′-(2,5-biphenylenedioxy)dibenzoyl chloride (1d) via a low temperature solution polycondensation reaction. A polyamide-hydrazide without the ether and pendant groups, poly[4-(terephthaloylamino)salicylic acid hydrazide, PTASH, is also investigated for comparison. It was synthesized from PASH and terephthaloyl chloride by the same synthetic route. The polymer intrinsic viscosities ranged from 4.5 to 2.47 dlg⁻¹ in N,N-dimethyl acetamide (DMAc) at 30 °C and decreased with the introduction of the ether and pendant groups into the polymer. All the polymers were soluble in DMAc, N,N-dimethyl formamide (DMF), and N-methyl-2-pyrrolidone (NMP) and their solutions could be cast into flexible films with good mechanical strengths. Further, they exhibited a great affinity to water sorption. Their solubility and hydrophilicity increased with introduction of the ether and pendant groups into the polymer. The prepared polymers could be thermally cyclodehydrated under nitrogen atmosphere into the corresponding poly(ether-amide-1,3,4-oxadiazole)s approximately in the region of 300–450 °C. The introduction of the flexibilizing ether linkages and the pendant groups into the polymer improves the solubility of the resulting poly(ether-amide-1,3,4-oxadiazole)s compared to poly(amide-1,3,4-oxadiazole) free from these groups.     

Rheology of concentrated solutions of hyperbranched polyesters

The solution rheology of different generations of hyperbranched polyesters in N‐methyl‐2‐pyrrolidinone (NMP) solvent was examined in this study. The solutions exhibited Newtonian behavior over a wide range of polyester concentrations. Also, the relative viscosities of poly(amidoamine) (PAMAM) dendrimers in ethylenediamine were compared with those of the hyperbranched polyesters in NMP. Both types of dendritic polymers have relative viscosities that are exponential functions of their molar fraction in solution. The slopes of these relative viscosity curves show a linear relationship with respect to the generation number. PAMAM dendrimers have the greater slopes for each generation, reflecting their relatively larger intrinsic viscosity values.     

Synthesis and properties of highly branched poly(urethane–imide) via A2 + B3 approach

A series of highly branched poly(urethane–imide) (HBPUI) were synthesized via A₂ + B₃ approach using isophorone diisocyante (IPDI), polycarbonatediol (PCDL), 3,3′,4,4′-Benzophen-onetetracarboxylic dianhydride (BTDA), and poly(oxyalkylene) triamine (ATA) as materials. The structure of the products was characterized by FT-IR and ¹³C-NMR. The molecular weights were characterized by gel permeation chromatograph (GPC). The solution viscosity, thermal, and mechanical properties were measured by rotational rheometer, differential scanning calorimetry (DSC), thermal gravimetric analysis (TGA), tensile tests, and dynamic mechanical analysis (DMA), respectively. The HBPUI showed lower viscosity than that of linear poly(urethane–imide) (LPUI), nevertheless T _g of HBPUI was higher than that of LPUI. TGA indicated that the thermal degradation of poly(urethane–imide) occurred above 300 °C, which was higher than conventional polyurethane. The tensile strength of HBPUI was obviously improved by increasing the content of BTDA and the molar ratio of [A₂]/[B₃]. The effects of the content of BTDA and the molar ratio of [A₂]/[B₃] on the storage modulus of the polymers were also studied.     

Poly(ether ketone azomethane)s and poly(ether ketone imide)s containing naphthylene moieties

A new diamine monomer, 1,5-bis[4-(4-aminophenoxy)]benzoyl-2,6-dimethoxynaphthalene, was synthesized via a Friedel–Crafts acylation reaction followed by an aromatic nucleophilic substitution reaction. Six ether–ketone linked polymers, named as poly(ether ketone azomethane)s and poly(ether ketone imide)s, were successfully prepared through the polycondensations of the diamine monomer with dialdehydes and dianhydrides, respectively. These naphthylated polymers exhibited high T _g values (142–288 °C), due to their bulky and rigid chemical structure. Meanwhile, they showed good thermal stability and improved solubility. Typically, some of them were casted into thin flexible film and showed high moduli.     

Electrochemical copolymerization and characterization of dianilines linked by polyether bridge with aniline

Copolymer of aniline and triethylene glycol bis(o-aminophenyl) ether was synthesized by constant potential electrolysis. Cyclic voltammogram of the copolymer films recorded in the monomer-free electrolytic solution revealed that the redox behavior of the films approaches to that of poly(triethylene glycol bis(o-aminophenyl) ether) with increasing amount of triethylene glycol bis(o-aminophenyl) in the feed ratio. Copolymerization was investigated by in situ recording the changes in the electronic absorption spectrum during electrolysis. The free standing copolymer film was characterized utilizing Fourier transform infrared spectrometer, and spectroelectrochemical behavior of the copolymer was investigated via in situ UV–vis spectroscopic technique. Besides the electron spin resonance study of the copolymer film, the different morphologies of the polymers were examined by scanning electron microscopy and the copolymerization was confirmed. The temperature dependence conductivity of the copolymer film was measured by four-probe technique in the temperature range of 100–300 K, and the calculated parameters showed that conduction mechanism fits to variable range hopping.     

Analysis of aromatic polyether dendrimers and dendrimer-linear block copolymers by matrix-assisted laser desorption ionization mass spectrometry

Summary Polyether dendrimers with differing chain end functionalites and molecular topologies were analyzed by MALDI-TOF mass spectrometry. The success of this analytical method is highly dependent on the type of matrix and sample preparation used. Ester and perdeuterophenyl terminated dendrimers with molecular weights up to 14,000 amu were successfully analyzed using an indoleacrylic acid matrix in tetrahydrofuran. Hybrid block copolymers consisting of linear polystyrene or poly (ethylene glycol) chains attached to one or two dendrimers gave spectra with oligomeric resolution in matrices of t-retinoic acid and 2-nitrophenyl octyl ether respectively. The MALDI-TOF results provide access to molecular weight distribution data confirming the results of size exclusion chromatography (SEC) analysis.     

A one-pot approach to dendritic star polymers via double click reactions

A class of well-defined dendritic star polymers with poly (ε-caprolactone) (PCLs) on the periphery has been prepared via one-pot double click reactions (Cu-catalyzed azide/alkyne click chemistry, i.e., CuAAC and Diels–Alder [4+2] cycloaddition reactions). The predecessors for Diels–Alder reaction, maleimide end-functionalized PCLs were produced by ring-opening polymerization (ROP). Obtained dendritic star polymers were characterized by ¹H NMR, size exclusion chromatography (SEC), UV/vis, and fluorescence spectroscopy.     

Thermal and Mechanical Properties of Poly(arylene ether ketone)s having Pendant Tertiary Butyl Groups

An aromatic bisphenol which contains bulky tertiary butyl group, 5-tert-butyl-1,3-bis(4-hydroxybenzoyl)benzene (2) was synthesized in high yield and purity by the reaction of 5-tert-butyl-1,3-bis(4-fluorobenzoyl)benzene with KOH solution in presence of DMSO. It was polymerized with activated bisarylhalides via aromatic nucleophilic substitution reaction to prepare a series of high molecular weight poly(arylene ether ketone)s (P1–P5), containing pendant tertiary butyl groups. The effect of molecular structure on the physical, thermal, mechanical and adhesion properties of the polymers were investigated. ^†Deceased. The paper is dedicated to Prof. Dr. Abdülkadir Kuyulu.     

Strain-promoted azide-alkyne cycloaddition “click” as a conjugation tool for building topological polymers

Strain-promoted azide-alkyne cycloaddition “click” reaction (SPAAC) was successfully used as a tool in synthesis of star polymers by grafting onto approach. The application of SPAAC method in star polymer synthesis was investigated for coupling reaction of the dibenzocyclooctyne (DIBO) end group of polystyrene (PS) and poly(ethylene glycol) (PEG) with coupling agents bearing 2, 3, or 4 azido groups. Firstly, well-defined linear DIBO-terminated PS was obtained by atom transfer radical polymerization (ATRP) of styrene using a DIBO containing ATRP initiator and linear DIBO-terminated PEG was obtained by terminal functionalization of PEG monomethyl ether (PEG-OH). Then a series of star PS and PEG bearing two, three and four arms were prepared respectively by subjecting SPAAC coupling reaction between the linear polymer-DIBO and the azido tethered core molecules at 30 °C without catalyst. The obtained star PS showed a well-defined structure after fractional precipitation to remove slightly excess linear polymers, and all the star polymers were characterized via Fourier transform infrared spectroscopy (FTIR), ¹H nuclear magnetic resonance spectroscopy (¹H NMR), size exclusion chromatography (SEC) and matrix-assisted laser desorption ionization-time-of-flight mass spectrometry (MALDI-TOF MS).     

Synthesis,characterization, and properties of co-poly(ether–urethane–urea)s containing lariat cryptand 22: Li<Superscript>+</Superscript> harvesting polymers

In this work, some segmented poly(ether–urethane–urea)s (PEUUs) containing aza crown ether (cryptand) were prepared and characterized. These polymers were synthesized via the reaction of kryptofix 22 with 2 mol excess of 4,4′-methylene-bis-(4-phenylisocyanate) (MDI), and different molecular weights of polyethylene glycols (PEGs). Morphology, thermal, and complexation properties of these polymers were studied by Fourier-transform infrared spectroscopy (FT-IR), differential scanning calorimetry (DSC), thermal gravimetric analysis (TGA), atomic absorption spectroscopy (AAS), and solid state NMR (S-NMR). The data confirmed complexation ability of these polymers for Li⁺ ion absorption and revealed the effect of Li⁺ ion complexation on the morphology and thermal behavior of the PEUUs.     

Polyurethane elastomers with amide chain extenders of uniform length

Toluene diisocyanate based polyurethanes with amide extenders were synthesized poly(propylene oxide) with a number average molecular weight of 2000 and endcapped with toluene diisocyanate was used as the polyether segment. The chain extenders were based on poly(hexamethylene terephthalamide): hexamethylene diamine, bisamine-diamide and bisamine-tetra-amide. The linear poly(ether bisurethane-bisurea-amide)s (PUA) were colorless transparent thermoplastic elastomers with a high molecular weight. The polymers were analyzed by IR and DSC, the morphology studied by TEM, the mechanical properties studied by DMTA and the tensile, the elastic properties by compression and tensile set and thermal stability by melt rheology.The phase separation with these amide extenders was by crystallization. Increasing the length of the amide chain extender increased the modulus and the melting temperature of the PUA without changing the good low temperature properties. Also the elastic properties improved with amide segment length. The fracture stress increases with amide extender length. At 200 °C, the melt stability of the PUA with the bisamine-diamide chain extender was good.     

Synthesis and characterization of poly(amide imides) containing benzimidazole-rings

New poly(amide imides) were prepared from benzimidazole-ring containing diamine via one-pot synthetic method. The diamine monomer, 6,4′-diamino-2-phenylbenzimidazole, was prepared from 4-nitrobenzoyl chloride and 4-nitro-1,2-phenylenediamine with 3 steps. It was found that the degree of imidization of the poly(amide imides) containing benzimidazole-ring can be controlled by monomer composition and solution imidization conditions. All partially imidized poly(amide imides) were soluble in polar aprotic solvent, but became insoluble in any organic solvents after thermal curing. The thermal stability of the poly(amide imides) increased as the polymers contain more benzimidazole units. Received: 6 March 1997/Accepted 2 April 1997     

Synthesis and Properties of Noncoplanar Rigid-rod Aromatic Polyamides Containing Phenyl or Naphthyl Substituents

A series of novel aromatic polyamides having noncoplanar biphenylene units in the main chain and bulky naphthyl or phenyl pendant group at 2,2′-disubstituted position were prepared from the two rigid-rod aromatic dicarboxylic acid monomers, 2,2′-diphenylbiphenyl-4,4′-dicarboxylic acid (1) and 2,2′-dinaphthylbiphenyl-4,4′-dicarboxylic acid (2), and various aromatic diamines. These polyamides were readily soluble in many organic solvents and showed excellent thermal stability associated with high glass-transition temperatures in the range of 229–292°C. These polymers also exhibited strong UV–Vis absorption bands at 262–353 nm in NMP solution, and their photoluminescence spectra showed maximum bands at 440–462 nm in the purple to blue region. The poly(amine–amide) IId derived from the diamine with triphenylamine moieties revealed excellent electrochromic contrast and coloration efficiency, changing color from the pale yellowish neutral form to green then to the blue oxidized forms when scanning potentials positively from 0.00 to 1.30 V. Figure Graphical Abstract. A series of novel aromatic polyamides having noncoplanar biphenylene units in the main chain and bulky naphthyl or phenyl pendant group at 2,2′-disubstituted position were prepared from the two dicarboxylic acids and various aromatic diamines. These polyamides were readily soluble in many organic solvents and showed excellent thermal stability associated with high glass-transition temperatures in the range of 229–292°C. These polymers also exhibited strong UV–Vis absorption bands at 262–353 nm in NMP solution, and their photoluminescence spectra showed maximum bands at 440–462 nm in the purple to blue region. The poly(amine–amide) IId derived from the diamine with triphenylamine moieties revealed excellent electrochromic contrast and coloration efficiency, changing color from the pale yellowish neutral form to green then to the blue oxidized forms when scanning potentials positively from 0.00 to 1.30 V.     

Synthesis and characterization of polyimides based on isopropylidene-containing bis(ether anhydride)s

Two bis(ether anhydride)s, 4,4′-[1,4-phenylenebis(isopropylidene-1,4-phenyleneoxy)]-diphthalic anhydride (IV _a) and 4,4′-[isopropylidenebis(1,4-phenylene)dioxy]diphthalic anhydride (IV _b), were prepared in three steps starting from the nucleophilic nitrodisplacement reaction of 4-nitrophthalonitrile with α,α ′-bis(4-hydroxyphenyl)-1,4-diisopropylbenzene (I _a) and 4,4′-isopropylidenediphenol (I _b) in N,N-dimethylformamide (DMF) in the presence of potassium carbonate. The bis(ether anhydride)s IV _a and IV _b were polymerized with various aromatic diamines to obtain two series of poly(ether amic acid)s VI _a–g and VII _a–g with inherent viscosities in the range of 0.30∼0.74 and 0.29∼1.01 dL/g, respectively. The poly(ether amic acid)s were converted to poly(ether imide)s VIII _a–g and IX _a–g by thermal cyclodehydration. Most of the poly(ether imide)s could afford flexible and tough films, and they showed high solubility in polar solvents such as N-methyl-2-pyrrolidone (NMP), N,N-dimethylacetamide, and m-cresol. The obtained poly(ether imide) films had tensile strengths of 45∼83 MPa, elongations-to-break of 6∼27%, and initial modulus of 0.6∼1.7 GPa. The T_gs of poly(ether imide)s VIII _a–g and IX _a–g were in the range of 194∼210 and 204∼243 °C, respectively. Thermogravimetric analysis (TG) showed that 10% weight loss temperatures of all the polymers were above 500 °C in both air and nitrogen atomspheres.     

Pervaporation of Organic Liquids from Binary Aqueous Mixtures using Poly(trifluoropropylmethylsiloxane) and Poly(dimethylsiloxane) Dense Membranes

In this work we have compared and contrasted the pervaporation behaviour (separation factor and flux) of fluorosilicone dense membranes based on poly(trifluoropropylmethylsiloxane) (PTFPMS) with poly(dimethylsiloxane) (PDMS) dense membranes. In particular, pervaporation experiments were carried out at 298 K using lab-made PTFPMS, lab-made PDMS and commercial PDMS membranes in order to remove three different organic liquids pyridine (PY), isopropanol (IPA) and methylethylketone (MEK) from dilute (<10 wt.%) binary aqueous mixtures. All of the silicone membranes studied were found to be successful for the desired separations. The permeation flux of pyridine–water liquid mixtures for the PTFPMS membranes was found to increase with the pyridine concentration in the feed mixtures. The separation factor for PDMS membranes for the removal of pyridine, IPA and MEK from aqueous binary mixtures (1 wt.%) was found to be higher than that of PTFPMS membranes while the normalized flux was higher for PTFPMS membranes under identical test conditions. The effect of crosslink density of the PTFPMS membranes on the separation of pyridine–water mixtures was also studied. For a 1 wt.% feed solution the total flux increased with the molar mass between crosslinks, whereas the separation factor for pyridine–water was highest for a molar mass between crosslinks of 15,320 g mol⁻¹.