摘要:

AbstractRecent developments in the field of reactive compatibilization of polymer blends prepared by melt processing focus on the addition of low molecular weight compounds. This work deals with in situ compatibilization through the formation of graft or crosslinked copolymers at the interface. Mixtures of semicrystalline hydrocarbon polymers have been subjected to free radical reactivity, in a co‐rotating twin screw extruder (ZSK 30) in a single step. The particular system, high density polyethylene and polyamide 6, was blended in the presence of a peroxide and a reactive bifunctional monomer, maleic anhydride. Because of a combined effect, the reaction appears to occur mainly at the interface, where the resulting grafted copolymer acts as an anchor for the final stabilization of the biphasic system. Different analytical techniques, such as differential scanning calorimetry, scanning electron microscopy and tensile testing, helped in characterizing the resulting blends and confirmed the high level of interfacial grafting and the expected improvement in mechanical propertie

ISSN:1042-7147    

DOI:10.1002/pat.1995.220061101

出版商:John Wiley&Sons, Ltd.    

年代:1995

数据来源: WILEY

摘要:

AbstractDepolymerization of poly(ethylene terephthalate), PET, waste was studied in the presence of manganese acetate catalyst and propylene glycol (PG) at different weight ratios. The glycolyzed products were analyzed for hydroxyl value and the amount of free glycol. A series of unsaturated polyesters based on the glycolyzed products, maleic anhydride and styrene, were prepared. Molecular weights and curing behavior of these polyesters were determined. Polymer concrete (PC) and polymer mortars (PM) made with these resins were investigated for their compressive strength. It has been found that the properties of PC and PM obtained from resins based on recycled PET are comparable to PC and PM made from virgin materials.

ISSN:1042-7147    

DOI:10.1002/pat.1995.220061102

出版商:John Wiley&Sons, Ltd.    

年代:1995

数据来源: WILEY

摘要:

AbstractThe solid‐phase rheology of a thermotropic polyester which is liquid crystalline in the melt (Vectra A) was studied for one‐dimensional finite‐amplitude deformations, including step‐strain and recovery, step‐stress and recovery, and step‐strain followed by small‐amplitude oscillations. The rheology is complex, and cannot be described by existing models. Below a critical strain, which is history‐dependent, Vectra A deforms as a linear viscoelastic solid. Above the critical strain the deformation is both viscoplastic and viscoelastic. There appears to be a maximum recoverable strain of about 0.03, beyond which all deformation is nonrecoverable. A large number of relaxation modes is required to describe the stress, and one time scale is inadequate to describe the time‐dependence of yielding

ISSN:1042-7147    

DOI:10.1002/pat.1995.220061103

出版商:John Wiley&Sons, Ltd.    

年代:1995

数据来源: WILEY

摘要:

AbstractElectroluminescent devices were fabricated using a holetransporting polymer, poly[N‐[p‐N′ ‐phenyl‐N′‐[1,1′‐biphenyl‐4′‐[N″‐phenyl‐N″‐(2‐methylphenyl)amino]‐4‐amino]]phenyl methacrylamide] (PTPDMA), and tris(8‐quinolinolato)aluminum(III) complex, Alq, as the hole transport layer and the emitter layer, respectively. A device structure of glass substrate/indium–tin–oxide/PTPDMA/Alq/Mg:Ag was employed. Hole injection from the electrode through the PTPDMA layer to the Alq layer and concomitant electroluminescence from the Alq layer were observed. Bright green luminescence with a luminance of 20,000

ISSN:1042-7147    

DOI:10.1002/pat.1995.220061104

出版商:John Wiley&Sons, Ltd.    

年代:1995

数据来源: WILEY

摘要:

AbstractThe electrochemical oxidation and reduction of the stable neutral nitroxyl radical gave the oxoaminium salt and hydroxylamine or nitroxyl anion, respectively. The electrochemical behavior of the N‐butylnitroxyl radicals or N‐butylhydroxylamines built in to various phenylenevinylene species were discussed in connection with its developed π‐conjugated structure based on cyclic voltammetric measurements. The aromatic nitroxyl radical showed two pairs of oxidation–reduction waves, but the acidic proton (hydroxylamine) changed its cathodic peak to a broad one with a shift to the anodic side. The π‐conjugated poly(phenylenevinylene) backbone and mobile proton of the hydroxylamine unstabilized the nitroxyl radical by retaining the

ISSN:1042-7147    

DOI:10.1002/pat.1995.220061105

出版商:John Wiley&Sons, Ltd.    

年代:1995

数据来源: WILEY

摘要:

AbstractPMR (polymerization of monomer reactants) ‐15 was formulated to use as a matrix resin for high performance carbon fiber‐reinforced composite materials. Monomers for the PMR‐15 were characterized using Fourier transform infrared spectroscopy. Molecular weight change during cure was investigated using gel permeation chromatography. Thermal analysis was carried out to investigate glass transition and thermal degradation. Cure behavior of a glass/PMR‐15 prepreg was investigated using a dynamic mechanical analyzer. Flexural strength of a cured carbon/PMR‐15 composite was affected by cure temperature and pressure. The morphology of the cured carbon/PMR‐15 was affected by cure conditions as well as by the surface conditions of the carbon fibers. A scanning electron micrograph of the composite made of untreated carbon fibers showed a void‐trapp

ISSN:1042-7147    

DOI:10.1002/pat.1995.220061106

出版商:John Wiley&Sons, Ltd.    

年代:1995

数据来源: WILEY

ISSN:1042-7147    

DOI:10.1002/pat.1995.220061107

出版商:John Wiley&Sons, Ltd.    

年代:1995

数据来源: WILEY