摘要:

AbstractPhoto‐oxidative degradation of blends of poly(ethylene terephthalate) (PET) and poly(2,6‐dimethyl‐1,4‐phenylene oxide) (PPO) was studied considering the mutual influence of both components. The photo‐oxidation of these systems was investigated in the temperature range 30–100°C to study the effects of segmental motion of polymer chains. For short time of UV‐illumination at 365 nm the process is diffusion controlled and can be explained with the help of Waite's theory. The segmental interactions of polymer segments in the blends also affect the diffusion coefficients and the activation energy values. Higher values of the activation energy of PET in the blends cause a decrease of

ISSN:0003-3146    

DOI:10.1002/apmc.1994.052140101

出版商:Hüthig&Wepf Verlag    

年代:1994

数据来源: WILEY

摘要:

AbstractElectroluminescence of thin films of poly(3,3‐phthalidylidene‐4,4′‐biphenylylene) (PPB) and poly(3,3‐phthalidylidene‐2,7‐fluorenylylene) (PPF) was studied. In both cases, electroluminescene was found to be of a threshold origin. Emission maxima and quantum efficiencies for PPB and PPF are 490 and 525 nm, 0.01 and 0.1%, respectively. The electroluminescent characteristics were found to be strongly dependent on the

ISSN:0003-3146    

DOI:10.1002/apmc.1994.052140102

出版商:Hüthig&Wepf Verlag    

年代:1994

数据来源: WILEY

摘要:

AbstractAcrylamide and acrylonitrile were polymerized with water‐soluble organic reducing compounds containing hydroxy groups such as methyl cellulose (MC), methyl hydroxy‐propyl cellulose (MHPC) and poly(ethylene glycol)s (PEG) in the presence of Ce(IV) in order to produce graft/block copolymers. The effect of cerium(IV) concentration, temperature, time and monomer concentration on the yield was studied. Copolymers of cellulose derivatives and polyacrylonitrile showed solubility properties similar to polyacrylonitrile. Both cellulose derivative‐polyacrylamide and poly(ethylene glycol)‐polyacrylamide copolymers were soluble i

ISSN:0003-3146    

DOI:10.1002/apmc.1994.052140103

出版商:Hüthig&Wepf Verlag    

年代:1994

数据来源: WILEY

摘要:

AbstractFluorine‐containing poly(benzoxazinone‐imide)s and poly(benzoxazinone‐phenyl‐quinoxaline‐imide‐amide)s have been synthesized by solution polycondensation of di‐acid dichlorides containing imide and hexafluoroisopropylidene groups with 4,4′‐di‐aminodiphenylmethane‐3,3′‐dicarboxylic acid or with mixtures of the latter with a di‐amino phenylquinoxaline. These polymers show high thermal stability, the decomposition temperatures being in the range of 450–470°C.Transparent flexible films were cast from the solutions of the corresponding polyamidic acid intermediates that after thermal cyclization showed low dielectric constant which recommends them for future ap

ISSN:0003-3146    

DOI:10.1002/apmc.1994.052140104

出版商:Hüthig&Wepf Verlag    

年代:1994

数据来源: WILEY

摘要:

AbstractPolyurethane/furfuryl alcohol (PU/FA) interpenetrating polymer networks (IPNs) were synthesized from furfuryl alcohol using p‐toluene sulfonic acid as a catalyst and blocked NCO‐terminated PU prepolymer with m‐xylylenediamine (MXDA) as a chain extender. From IR spectrum analysis it was found that the major reactions in the PU/MXDA/FA system are the polymerization of PU/MXDA and the self‐polymerization of FA. The tensile strengths of PU/FA IPNs that contain 5 p.h.r. PU are greater than those of the pure components. The flexural strength, flexural modulus, Shore D hardness and HDT decrease and the notched Izod impact strength increases with the polyurethane content. The compatibility of the compounds in these PU/FA IPNs was investigated by dynamic mechanical analysis and scanning electron microscopy. It was found that glass transition temperatures are shifted inwardly which indicated that the PU/FA IPNs were semicompatible. It was confirmed from scanning electron micrography that the system was hetero

ISSN:0003-3146    

DOI:10.1002/apmc.1994.052140105

出版商:Hüthig&Wepf Verlag    

年代:1994

数据来源: WILEY

摘要:

AbstractPositive and negative photostructures are formed after the polyimide (PI) of 4,4′‐biphthalic anhydride (BPA) and 4,4′‐diamino‐3,3′‐dimethyldiphenylmethane (DADMDPM), PI(BPA/DADMDPM) is doped with Michler′s ketone (MK) and benzophenone (BP), respectively, and is subjected to UV light (400 ± 50 nm) irradiation and solvent development. The principle of positive feature formation is based on the photocoupling of MK with PI, which increases PI solubility and thus enables a positive pattern to be developed. The phenomenon of negative photopatterning results from intermacromolecular H‐bonding between the carbonyl group of the imide ring and the hydroxy group which is formed in the photoinduced coupling reaction between BP and PI. Lithographic evaluation shows that the MK‐doped positive‐acting PI film cannot form useful patterns because UV wavelengths are strongly absorbed by MK, which limits the depth of photocoupling in the film. On the other hand, 2‐μm‐wide lines can be resolved in the BP‐doped negativ

ISSN:0003-3146    

DOI:10.1002/apmc.1994.052140106

出版商:Hüthig&Wepf Verlag    

年代:1994

数据来源: WILEY

摘要:

AbstractThe photochemical behaviour of some polyurethane zwitterionomers containing azoaromatic structures of dye type was studied both in solution and polymer film. The interaction between methyl orange and the sulfobetaine structures of the polyurethane chain was followed by electronic absorption spectra.

ISSN:0003-3146    

DOI:10.1002/apmc.1994.052140107

出版商:Hüthig&Wepf Verlag    

年代:1994

数据来源: WILEY

摘要:

AbstractSodium alginate was graft‐copolymerized with ethyl acrylate using ceric ammonium nitrate as an initiator. In order to optimize the conditions for grafting, the concentrations of nitric acid, initiator and monomer together with temperature, time and amount of substrate were varied. The kinetic scheme of free radical graft copolymerization has been proposed and the equations relating the values of rate of polymerization, rate of graft copolymerization and rate of homopolymerization are also suggested. The experimental results agree very well with the proposed kinetic schem

ISSN:0003-3146    

DOI:10.1002/apmc.1994.052140108

出版商:Hüthig&Wepf Verlag    

年代:1994

数据来源: WILEY

摘要:

AbstractMechanical properties of polypropylene‐talc composites are measured as a function of talc concentration up to 40 wt.‐%, Young's modulus of filled polypropylene shows linear increase with talc concentration up to double the value of unfilled polymer. Yield stress and Charpy notch toughness decrease with increasing talc content below matrix level at the highest filler content. Composite ultimate tensile elongation and tensile impact strength decrease sharply beginning at the lowest filler concentration. The influence of the talc particle size on the mechanical properties, especially composite toughness, mentioned above, is investigated. Four type of talc were used. Notch toughness decreases according to a linear dependence with mean size of talc particles. Evaluating impact strength possible content of agglomerates of filler and other additions is necessary to be included: tensile impact strength gives slow linear dependence with increasing content of filler particles and/or agglomerates above about 10 μm. The influence of talc particle size on the toughness of filled polypropylene becomes strong if the rubber particles are pre

ISSN:0003-3146    

DOI:10.1002/apmc.1994.052140109

出版商:Hüthig&Wepf Verlag    

年代:1994

数据来源: WILEY

摘要:

AbstractPoly(etheraroylhydrazide) is synthesized in the presence of PA6 by means of low‐temperature condensation polymerization of 4,4′‐dichloroformyl‐α,ω‐diphenoxydodecane with terephthaloyl dihydrazide (TDH) in order to prepare polyhydrazide/poly‐amide 6 (PEHZ12/PA6) blends. The thermal analysis of the blends by DSC seems to indicate that the two polymers are not interacting. Nevertheless, when the blends are subjected to an extraction process with formic acid in order to remove the PA6, the characterization of the residual PEHZ12 reveales that some interactions do occur between the constituent polymers, at least for selected compositions. Model experiments permit to hypothesize that the polymerization of PEHZ12 proceeds with a chemical interaction between amino end groups of PA6 and growing

ISSN:0003-3146    

DOI:10.1002/apmc.1994.052140110

出版商:Hüthig&Wepf Verlag    

年代:1994

数据来源: WILEY