PHYSICAL AGING OF HIGH-PERFORMANCE THERMOPLASTICS - ENTHALPY RELAXATION IN PEK-C AND PES-C

The developments of physical aging in phenolphthalein poly(aryl-ether-ketone) (PEK-C) and poly(aryl-ether-sulfone) (PES-C) with time at two aging temperatures up to 20 K below their respective glass transition temperatures (T-g = 495 and 520 K) have been studied using differential scanning calorimetry (DSC). Substantial relaxation within the aging course of several hours were observed by detecting T-g decreasing during physical aging process at the two aging temperatures. The relaxation processes of both polymers are extremely nonlinear and self-retarding. The time dependencies of their enthalpies during the initial stages of annealing were approximately modeled using the Narayanaswamy-Tool model. The structure relaxation parameters obtained from this fitting were used to predict the possibility of physical aging occurring at their respective using temperatures. (C) 1995 John Wiley and Sons, Inc.

POLY(AZOMETHINE SULFONES) WITH THERMOTROPIC LIQUID-CRYSTALLINE BEHAVIOR

New poly(azomethine sulfones) with linear structures containing sulfonyl bis(4-phenoxyphenylene) and oxo bis(benzylideneaniline) or methylene bis(benzylideneaniline) units were prepared in the conventional literature manner by condensing the dialdehyde sulfone monomer (V) with diamines such as 4,4'-oxydianiline (IIIa) and 4,4'-methylenedianiline (IIIb), or by condensing an azomethine biphenol (IX) with 4,4'-sulfonyldichlorobenzene (II). Three model compounds which reproduced the above structures were also synthesized. The resulting polymers were confirmed by IR, H-1-NMP, and elemental analysis, and were characterized by inherent viscosities, thermogravimetric analysis (TGA), and x-ray diffraction. The thermotropic liquid crystalline (TLC) behavior was studied using polarization light microscopy (PLM), thermooptical analysis (TOA), and DSC. A nematic texture was observed only for 4,4'-oxydianiline-units-based polymers. The reaction of polymer VIIIb containing -CH2- links between the mesogens with the model compound IX led to polymer X which exhibited TLC behavior.

ARYLIDENE COPOLYETHER SULFONES .2. SYNTHESIS END CHARACTERIZATION OF SOME NEW COPOLYETHER SULFONES CONTAINING DIBENZYLIDENE CYCLOHEXANONE MOIETIES

New copolyether sulfones containing 2,6-bis(p-oxo-benzylidene)cyclohexanone and 2,6-bis(o,p-dioxo-benzylidene)cyclohexanone moieties were prepared in the conventional literature manner by condensing the dipotassium salts of 2,6-bis(p-hydroxybenzylidene)cyclohexanone (III), 2,6-bis(o,p-dihydroxybenzylidene)-cyclohexanone (V), and 2,2-bis(p-hydroxyphenyl)propane (Bisphenol A, VII) with 4,4'-dichlorodiphenyl sulfone (VI), or by condensing the dipotassium salts of III and VII with a new benzylidene cyclohexanone sulfone macromer (X). Finally, the polycondensation reaction of sulfonyl bis(p-benzaldehydeoxo-p-phenylene) (IX) with cyclohexanone leads to an unsaturated copolymer (XVI). The resulting copolyether sulfones were confirmed by IR, H-1-NMR, viscometry, elemental analysis, thermooptical (TOA), x-ray, and thermogravimetric (TGA) measurements.

STRUCTURE AND PROPERTIES OF AB CROSS-LINKED POLYMERS

Hydroxy-terminated oligomers, such as polyester, polyether, or castor oil, were reacted with toluene diisocyanate to form isocyanate-terminated prepolymers, which were then reacted with 2-hydroxyethyl acrylate to obtain vinyl-terminated prepolymer (VTP).

PENDANT FUNCTIONAL-GROUP COPOLYETHER SULFONES .1. SYNTHESIS AND CHARACTERIZATION OF NEW COPOLYETHER SULFONES WITH PENDANT ALDEHYDE GROUPS MODIFIED INTO PHENOLIC AZOMETHINE GROUPS

New functional copolyether sulfones with pendant aldehyde groups were synthesized by the classical polycondensation reaction between 4,4' -dichlorodiphenyl sulfone (I) and various bisphenols such as 5,5'-methylene bis-salicylaldehyde (II-2), 2,2-bis( 4-hydroxyphenyl)propane (III), and 2,6-bis(4-hydroxybenzylidene)cyclohexanone (IV). Condensation reaction with 4-aminophenol led to pendant phenolic azomethine groups containing copolyether sulfones. The structures of the resulting polymers were confirmed by IR, H-1-NMR spectra, and elemental analyses. The polymers were characterized by reduced viscosity, solubility, thermal stability, DSC, and x-ray diffraction measurements.

ARYLIDENE COPOLYETHER SULFONES .1. SYNTHESIS AND CHARACTERIZATION OF SOME NEW COPOLYETHER SULFONES CONTAINING DIBENZYLIDENE CYCLOPENTANONE MOIETIES

New copolyether sulfones containing 2,5-bis(4-oxo-benzylidene)-cyclopentanone moieties were prepared in the conventional literature manner by condensing the dipotassium salts of 2,5-bis(4-hydroxybenzylidene)cyclopentanone (I) and 2,2-bis(4-hydroxyphenyl)propane (Bisphenol A, III) with 4,4'-dichlorodiphenyl sulfone (II), or by condensing the dipotassium salts of I with chlorine-terminated Bisphenol A-4,4'-dichlorodiphenylsulfone copolymers (V). The resulting copolyether sulfones were confirmed by IR, viscometry, DSC measurements, thermooptical analysis (TOA), and thermogravimetric analysis (TGA).

Highly brominated mono- and bis-phenols from the marine red alga Symphyocladia latiuscula with radical-scavenging activity

Four new highly brominated and fully substituted mono- and bis-phenols, 1-(2,3,6-tribromo-4,5-dihydroxybenzyl)pyrrolidin-2-one (1), 1,2-bis(2,3,6-tribromo-4,5-dihydroxyphenyl)ethane (2), 6-(2,3,6-tribromo-4,5-dihydroxybenzyl)-2,5-dibromo-3,4-dihydroxybenzyl methyl ether (3), and 2,3,6-tribromo-4,5-dihydroxybenzyl methyl sulfone (4), were characterized from the marine red alga Symphyocladia latiuscula. In addition, five known bromophenols, bis(2,3,6-tribromo-4,5-dihydroxyphenyl)methane (5), bis(2,3,6-tribromo-4,5-dihydroxybenzyl) ether (6), 2,3,6-tribromo-4,5-dihydroxybenzyl methyl ether (7), 2,3,6-tribromo-4,5-dihydroxymethylbenzene (8), and 2,3,6-tribromo-4,5-dihydroxybenzaldehyde (9), were also isolated and identified. The structures of these compounds were elucidated by spectroscopic methods including 1D and 2D NMR as well as by low- and high-resolution mass spectrometric analysis. Structurally, all of these compounds are highly brominated and fully substituted, and contain one or two 2,3,6-tribromo-4,5-dihydroxyphenyl unit(s) in each of the molecules. In addition, compound 4 possesses a unique sulfone structural feature. Each of the isolated compounds was evaluated for alpha,alpha-diphenyl-beta-picrylhydrazyl (DPPH) radical-scavenging activity and all were found to be potent, with IC50 values ranging from 8.1 to 24.7 mu M, compared to the known positive control butylated hydroxytoluene (BHT), with an IC50 of 81.8 mu M.

Halogenated Terpenes and a C-15-Acetogenin from the Marine Red Alga Laurencia saitoi

Seven parguerane diterpenes: 15-bromo-2,7,19-triacetoxyparguer-9(11)-en-16-ol (1), 15-bromo-2,7,16,19-tetraacetoxyparguer-9(11)-ene (2), 15-bromo-2,19-diacetoxyparguer-9(11)-en-7,16-diol (3), 15-bromo-2,16,19-triacetoxyparguer-9(11)-en-7-ol (4), 15bromo-2,16-diacetoxyparguer-9(11)-en-7-ol (5), 15-bromoparguer-9(11)-en-16-ol (6), 15-bromoparguer-7-en-16-ol (7), two polyether triterpenes: thyrsiferol (8) and thyrsiferyl 23-acetate (9), and one C15-acetogenin, neolaurallene (10), were isolated from a sample of marine red alga Laurencia saitoi collected off the coast of Yantai. Their structures were established by detailed NMR spectroscopic analysis and comparison with literature data.

Preparation of a novel polysulfone/polyethylene oxide/silicone rubber multilayer composite membrane for hydrogen-nitrogen separation

A novel poly sulfone/polyethylene oxide/silicone rubber (PSOPEO/SR) multilayer composite membrane was fabricated by double coating polysulfone substrate membrane with polyethylene oxide and silicone rubber. Gas permeation experiments were performed at 30 degrees C for hydrogen and nitrogen. PSf(PEO/SR membrane displayed high and steady performance for H-2/N-2: permeances of H-2 and N-2 of 49.51 and 0.601 GPU, respectively, and H-2/N-2 ideal separation factor of 82.3. It was explained that layer interfaces due to the introduction of PEO layer act as the permselective media and are responsible for the higher H-2/N-2 ideal separation factor which has exceeded the intrinsic permselectivities of the three polymers used in this study. (c) 2005 Elsevier B.V. All rights reserved.