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1.
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. 相似文献
2.
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. 相似文献
3.
Hassan Ebadi-Dehaghani Shahram Mehdipour-Ataei 《Journal of Inorganic and Organometallic Polymers and Materials》2012,22(1):223-234
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. 相似文献
4.
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 相似文献
5.
The number average molar mass Mn 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 Mu for PODMA. True number-average molar masses Mn (true) calculated using the new calibration are approximately twice the apparent molar mass Mn (app) based on a PS calibration for higher molar mass samples (>10?000 g mol−1). 相似文献
6.
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. 相似文献
7.
Anthony L. Andrady Carlos M. Nunez Bor‐Sen Chiou Saad A. Khan 《Polymer Engineering and Science》2002,42(11):2065-2071
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. 相似文献
8.
Ming Zhu Xiao Liu Baijun Liu Zhenhuan Jiang Toshihiko Matsumoto 《Polymer Bulletin》2011,67(9):1761-1771
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. 相似文献
9.
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. 相似文献
10.
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. 相似文献
11.
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. 相似文献
12.
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. 相似文献
13.
Emel Yıldız Tülay Yılmaz İnan Hüseyin Yıldırım Abdülkadir Kuyulu Atilla Güngör 《Journal of Polymer Research》2007,14(1):61-66
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. 相似文献
14.
Shadpour Mallakpour Fatemeh Rafiemanzelat Mohammad Ali Zolfigol Peyman Salehi Ding Yah Yang 《Polymer Bulletin》2011,67(4):553-569
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. 相似文献
15.
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). 相似文献
16.
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. 相似文献
17.
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 相似文献
18.
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. 相似文献
19.
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 Tgs 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. 相似文献
20.
Xiao Kang Zhang Yadagiri Poojari Lee Ellen Drechsler Chung Mien Kuo Joel R. Fried Stephen J. Clarson 《Journal of Inorganic and Organometallic Polymers and Materials》2008,18(2):246-252
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. 相似文献