ABSTRACT Azo disperse dyes containing N, N-diethylol group have been prepared and each dye was polycondensed with 4,4′ -Diphenyl methane diisocyanate. The resultant colored polyurethanes were characterized by nitrogen content, IR spectral studies, number average molecular weight ([Mbar]n), estimated by conductometric titration, and thermogravimetry. The electrical conductivity of all the polyurethanes was measured at room temperature. 相似文献
Poly(amido-imide)s (PAI) were prepared by the intermolecular Diels-Alder (DA) reaction of 1,1-(sulfonyldi-4,1-phenylene) bis[(2-furanyl methylamino) acetamide] (SPBFA) with various bis(maleimide)s. The DA reaction was carried out in tetrahydrofuran as a solvent, as well as in bulk, followed by aromatization of sodium acetate intermediates in the presence of acetic anhydride. All the polymers were characterized by elemental analysis, infrared (IR) spectral studies, and thermogravimetry. The PAI exhibit moderate thermal stability. The SPBFA and bis(maleimide)s were polymerized (at 145±10°C) by in situ DA intermolecular reaction into moderately thermally stable PAI-glass fiber composite laminates and were characterized by their chemical resistance and mechanical properties. 相似文献
Poly(ester amido imide)s (PEAI)s (IIIa–e) were prepared by the intermolecular Diels-Alder (DA) reaction of bismaleimide (II) having epoxy resin segment with various bisfurans (Ia–e) having amide bridge. The DA reaction was carried out with tetrahydrofuran as a solvent, as well as in bulk, followed by aromatization of DA polyadduct intermediates in the presence of acetic anhydride. All the resultant polymers, designated as poly(ester amido imide)s (PEAI)s, were characterized by elemental analysis, number average molecular weight, IR spectral studies and thermogravimetry. The PEAIs exhibit good thermal stability. Bismaleimide (II) and bisfurans (Ia–e) were polymerized (at 150 ± 10°C) by in situ DA intermolecular reaction into moderately thermally stable PEAIs. The glass fiber-reinforced composites (i.e., laminates) of all PEAIs were prepared and characterized by their chemical resistance and mechanical properties. 相似文献
Bis(4‐fluoro‐3‐trifluoromethylphenyl)phenylphosphine oxide is synthesized and six new poly(arylene ether)s are prepared by nucleophilic displacement of the fluorine atom on the benzene ring by several diphenols under basic conditions. The products show very high glass transition temperatures of up to 252 °C and very good thermal stabilities of up to 490 °C for 5% weight loss. The polymers display very low heat release rates in the microscale combustion calorimeter test, suggesting good flame retardance. All polymers are soluble in a wide range of organic solvents. Transparent thin films cast from dichloromethane exhibit tensile strengths up to 54 MPa, a modulus of elasticity up to 0.97 GPa and elongation at break up to 47% depending on their exact repeating unit structures.
Several new poly(ester-imide)s were prepared by direct polycondensation reaction of 1,1-bis[4-(trimellitimido)phenoxy]methane 6 with various aromatic diols 7a-f in a system of tosyl chloride (TsCl), pyridine (Py), and N,N-dimethylformamide (DMF). The reactions with TsCl were significantly promoted by controlling alcoholysis with diols, in the presence of catalytic amounts of DMF, to give a series of poly(ester-imide)s. The resulted polymers were characterized by FTIR and 1H-NMR spectroscopy. Also, thermal properties of the PEIs 8a-f were investigated using thermal gravimetric analysis (TGA) and differential scanning calorimetry (DSC). 相似文献
Poly(urea-imide)s (PUIs) were prepared by Diels-Alder (DA) intermolecular polymerization of hexamethylenebis(2-furanmethylurea) (BFU) (1) with various bismaleimides (2a-f). The DA reaction was carried out using 1,4-dioxane as solvent, as well as in bulk, followed by aromatization (dehydration) of poly(tetrahydro phthalimide) intermediates (3a-f) in the presence of acetic anhydride. All the PUIs (3a-f, 4a-f and 5a-f) were characterized by elemental analysis, IR spectral studies and thermogravimetrically. BFU (1) and bismaleimides (2a-f) were polymerized (at 145 ± 10°C) by in situ DA intermolecular reaction into moderately thermally stable PUIs (5a-f), glass fiber and carbon fiber composites without evolution of any byproducts. The prepared composites were characterized by chemical resistance and mechanical properties. 相似文献
Summary: A new series of thermoplastic poly(urethane‐imide)s (TPUI1‐4) containing hydroxyl groups in the backbone was synthesized from the reaction of epoxy‐terminated polyurethane prepolymers (EPU1‐4) and an imide containing diacid (DIDA) chain extender under optimized reaction conditions. EPU1‐4 was prepared through end‐functionalization of NCO‐terminated polyurethanes based on polyester polyol (CAPA) and hexamethylene diisocyanate with glycidol. A blocked isocyanate (BIC) was made from the reaction of trimethylol propane (TMP), toluene diisocyanate (TDI) and N‐methylaniline (NMA). Polymer networks were prepared from the reaction of librated isocyanate groups of BIC with hydroxyl groups of TPUIs. The starting materials and polymers were characterized by conventional spectroscopic methods and the physical, thermal and electrical properties of crosslinked networks were studied. Investigation of the recorded properties for these samples showed considerable improvement in thermal and electrical properties in comparison to common polyurethanes.
This study aimed at examining the properties of blends of semi-crystalline polydioxanone (PDX) and amorphous poly(methyl dioxanone) (PMeDX). The authors show that low amounts of PMeDX, within 15 wt% acts as plasticizer to high molar mass PDX as confirmed by an increase in Young's modulus of films. The plasticizing effect on blends increased with decreasing reduced viscosity of PMeDX. Mechanical tests showed overall reduced tensile properties of the blends. Viscosity analysis coupled with SEM and AFM indicated immiscibility of the blends over the whole range of compositions. Blend samples with higher PMeDX contents degraded at faster rates with profiles differing from PDX. 相似文献