摘要:

AbstractPhotochemical processes occurring in polystyrene films containing dicumyl peroxide (DCP), in the presence of octadecyl 3‐(3,5‐di‐tert‐butyl‐4‐hydroxyphenyl)propionate (Irganox 1076) were investigated. It was found, that Irganox 1076 reduces the photo‐oxidation and photo‐degradation of polystyrene when DCP is used as an initiator of the processes and polymer samples are irradiated with light of λ

ISSN:0025-116X    

DOI:10.1002/macp.1982.021830711

出版商:Hüthig&Wepf Verlag    

年代:1982

数据来源: WILEY

摘要:

AbstractPolymers containing 1‐trifluoromethylvinylene, 1,4‐phenylene, and/or 2,5‐thiophenediyl units (6a,band8a‐d), obtained by base‐free Wittig condensation reactions with phase transfer catalysts, were investigated combining direct evaporation in the ion source of a double focusing mass spectrometer with the “Linked‐Scan” metastable technique. This method could be shown to allow the unequivocal identification and differentiation of components in polymers up to high mass regions (m/z≤ 3000). The degree of polycondensation up to 18 aromatic/heteroaromatic units in the chain was determined by mass chromatography, which correlated with the HPLC results. Terminal groups and sequence ions were characterized by comparison of metastable transitions of selected ions with model compounds. Detailed information on the polycondensation reaction was obtained. In addition to linear products, cyclic species with 3 to 18 arylene‐1‐trifluoromethylvinylene units were formed. The main fragmentations may be explained by sterical effects of both the α‐trifluoromethylstilbene moiety and the heteroaromatic analogues

ISSN:0025-116X    

DOI:10.1002/macp.1982.021830712

出版商:Hüthig&Wepf Verlag    

年代:1982

数据来源: WILEY

摘要:

AbstractThe kinetic results (from DSC and1H NMR) of the thermolysis of symmetric azochloroalkanes and azoalkyl acetates with the general structure R1R2(X) C—N=N—C(X) R1R2(X=OCOCH3, Cl; R1, R2=CH3, C6H5) and of asymmetric phenylazoalkyl acetates with the general structure R1R2(H3COCO) C—N=N—C6H5(R1R2=CH3, C6H5) are described. The suitability of the asymmetric compounds as initiators for radical polymerization is demonstrated with (diphenyl)phenylazomethyl acetate (7c). Quantitative measurements of the thermolysis products from 1,1′‐azo(methylethyl) diacetate (4a) showed that the ratio for the disproportionation to combination reaction of the resulting substituted alkyl radi

ISSN:0025-116X    

DOI:10.1002/macp.1982.021830713

出版商:Hüthig&Wepf Verlag    

年代:1982

数据来源: WILEY

摘要:

AbstractBy reaction of poly[2‐(1‐naphthyl)‐1,3‐dioxan‐4,6‐diylmethylene] (3), poly[2‐(2‐naphthyl)‐1,3‐dioxan‐4,6‐diylmethylene] (5), poly[2‐(9‐isobutyl‐3‐carbazolyl)‐1,3‐dioxan‐4,6‐diylmethylene] (7) and poly[2‐((S)‐9‐(2‐methylbutyl)‐3‐carbazolyl)‐1,3‐dioxan‐4,6‐diylmethylene] (9) with 3,5‐dinitrobenzoylchloride (12) or 4,5,7‐trinitro‐9‐fluorenone‐2‐carboxylic acid chloride (2) polymeric intramolecular charge‐transfer‐complexes (4a,4b,6,8a,8b, and10) were synthesized. The polymers were investigated by means

ISSN:0025-116X    

DOI:10.1002/macp.1982.021830714

出版商:Hüthig&Wepf Verlag    

年代:1982

数据来源: WILEY

摘要:

AbstractThe kinetics of the polymerization of styrene with oligostyryllithium and butyllithium in the presence of electron donors was investigated calorimetrically. There is no simple correlation between the accelerating effect (1,2‐dimethoxyethane>tetrahydrofuran>N,N,N′,N′‐tetramethylethylenediamine = triethylamine) of the individual electron donors upon the polymerization and their ability to form complexes with the respective organolithium compounds. This is qualitatively explained by considering preceding coordination reactions between organolithium compounds (or their complexes with electron donors) and the monomer in the reaction scheme. An irreversible degradation reaction between butyllithium and 1,2‐dimethoxyethane occurring atT>278 K is described. The products of this reaction are lithium methoxide, decane and hexyl met

ISSN:0025-116X    

DOI:10.1002/macp.1982.021830715

出版商:Hüthig&Wepf Verlag    

年代:1982

数据来源: WILEY

摘要:

AbstractPolyester prepolymers, prepared from maleic anhydride and diethylene glycol were cured with styrene using benzoyl peroxide as the catalyst and tertiary amines as accelerators. The effect of the accelerators on curing rates and efficiencies and resin properties was studied when the accelerators were chemically incorporated into the polyester prepolymer versus when the same accelerators were free. The accelerators employed were diethylaniline (1);N,N‐bis‐(2‐hydroxyethyl)aniline (2);N,N‐bis(2‐hydroxyethyl)propylamine (3);N,N‐bis(2‐hydroxyethyl)‐isopropylamine (4);N,N‐bis(2‐hydroxyethyl)butylamine (5); and dimethylaniline. The efficiency of the free accelerators decreased in the order dimethylaniline>1>2>4>3>5. Each of the accelerators,2–5, were significantly more efficient when incorporated into the polymer chain than when they were used free according to measured curing times, pot life, and gel times. Furthermore, the initiation energies for polymer‐bound accelerators3, 4, and5are significantly lower than those obtained when these same accelerators are added free. Polymerbound accelerators2, 3, 4, and5gave resins with higher Brinell's hardness, higher tensile strengths, higher softening points, and lower extractable fractions than were obtained for resins prepared with identical amounts of the corresponding free accelerators. Mechanisms to account for thes

ISSN:0025-116X    

DOI:10.1002/macp.1982.021830716

出版商:Hüthig&Wepf Verlag    

年代:1982

数据来源: WILEY

摘要:

AbstractThe interactions between sodium dodecyl‐ and tetradecylsulfater or sodium alkylbenzenesulfonate and a copolymer ofN‐vinylpyrrolidone with vinylamine (9 : 1 by mole) in aqueous solution were investigated by polarized luminescene. Polymer complexes of these anionic detergents with the copolymer were obtained and their antimicrobial and toxic properties as well as their effect on a bacterial enzyme, penicillinase, were investigated, It was found that these polymer complexes do not disintegrate on passing from aqueous to salt solutions, are 4 to 5 times less toxic than the initial anionic detergents and are comparable to the latter in both their antimicrobial activity and the ability for inhibiting penicillin

ISSN:0025-116X    

DOI:10.1002/macp.1982.021830717

出版商:Hüthig&Wepf Verlag    

年代:1982

数据来源: WILEY

摘要:

AbstractA new method based on the inversion of a relation derived by Krathy, and thereby allowing the determination of the orientation distribution function of amorphous polymers by Wide Angle X‐Ray Scattering (WAXS), is described. With a simple approximation, in many cases disturbing intramolecular scattering can be separated from the measured azimuthal intensity distribution along the first maximum of the amorphous halo. For oriented amorphous poly(ethylene terephthalate), the 2nd and 4th moments of the determined orientation distribution functions agree very well with those from birefringence and spectroscopic measurements. The method is not applicable to partially crystalling polymers, because the approximation for intramolecular scattering does no longer hold. Finally, the intrinsic birefringence of bisphenol‐A‐polycarbonate was determined by this method to be 0,236 ±

ISSN:0025-116X    

DOI:10.1002/macp.1982.021830718

出版商:Hüthig&Wepf Verlag    

年代:1982

数据来源: WILEY

摘要:

AbstractThe aim of this study is to characterize the state of progress of a polymerization reaction by a non‐destructive electric method. For this purpose, results deduced from measurements of complex permittivity are compared with those obtained from chemical analysis of the reaction mixture at successive instants of its evolution. Chemical analysis allows the rate of disapperace of expoxy groups during the polymerization reaction in liquid phase to be evaluated. Exploitation of electric measurements of complex relative permittivity enables the evolution of the polymerization to be followed from both the product of the epoxy group concentration and the square of the mean value of their dipole moment and also from the most probable relaxation time of this dipole. As expected, the variations of relaxation time are closely correlated to those of the viscosity of the mediu

ISSN:0025-116X    

DOI:10.1002/macp.1982.021830719

出版商:Hüthig&Wepf Verlag    

年代:1982

数据来源: WILEY

摘要:

AbstractIntramolecular excimer formation between pyrenes attached to the ends of a poly(ethyleneoxide) sample of nominal molecular weight 9600 has been examined in twelve solvents. In ten non‐protic solvents the excimer to pyrene locally excited fluorescene intensity ratioIE/IMis inversely proportional to solvent viscosity, as expected for a diffusion‐controlled process. Similar results were obtained for 〈k1〉 values obtained from flash‐photolysis studies, where 〈k1〉 is the average rate constant for end‐to‐end cyclization in the polymer. In water and methanol, the extent of excimer emission and the rate of intramolecular excimer emission and the rate of intramolecular excimer formation were substantially greater than one would infer on the basis of solven

ISSN:0025-116X    

DOI:10.1002/macp.1982.021830720

出版商:Hüthig&Wepf Verlag    

年代:1982

数据来源: WILEY