摘要:

AbstractCopolymerizations of pyrrolidone‐2 (γ‐butyrolactam) with piperidone‐2 (δ‐valerolactam) and azepinone‐2 (ε‐caprolactam) and the copolymerization of piperidone‐2 with azepinone‐2 were studied in bulk at 30 or 45°C. The sodium salt and the tetramethylammonium salt of pyrrolidone‐2 were used as catalysts andN‐acetylpyrrolidone‐2 as cocatalyst. The sequences of the resulting copolyamides were analyzed by means of 22.63‐MHz13C‐NMR spectra. All sequences were nearly random in nature, yet copolymerizations of pyrrolidone‐2 favor slightly the formation of alternating sequences. Furthermore, the rate of incorporation of pyrrolidone is higher than that of the two comonomers in contrast to experiments at temperatures above 100°C. The influence of transamidation reactions on the sequences is discussed. Propagation/degradation equilibria involvingN‐acyllactam chain ends were found to modify the initially formed, kinetically controlled sequences in direction of

ISSN:0360-6376    

DOI:10.1002/pol.1982.170200901

出版商:John Wiley&Sons, Inc.    

年代:1982

数据来源: WILEY

摘要:

AbstractThe kinetics of the aqueous polymerization of methyl methacrylate initiated by potassium peroxydisulfate–citric acid catalyzed by silver ion was investigated in nitrogen atmosphere. The rate of polymerization is proportional to the square root of peroxydisulfate concentration. The initial rate increases with increasing citric acid concentration up to 15 × 10−3M, after which it decreases. The rate of polymerization also increases initially with monomer concentration and decreases at higher monomer concentration. The effects of temperature and the addition of some solvents and salts on the rate of polymerization have also been studied and a suitable kinetic scheme has been proposed for the reac

ISSN:0360-6376    

DOI:10.1002/pol.1982.170200902

出版商:John Wiley&Sons, Inc.    

年代:1982

数据来源: WILEY

摘要:

AbstractThe title compound was synthesized by hydrogenolysis of its precursor 2,2‐bis(4‐trifluoromethanesulfonatophenyl)hexafluoropropane (2) in the presence of a base. 2,2‐Diphenylhexafluoropropane (6) can be appropriately functionalized at the 3,3′‐positions to give the diamino (7), dibromo (11), dicarboxaldehydo (13), 3‐ethynyl‐3′‐carboxaldehydo (14) derivatives which are important monomers in the synthesis of various high‐temperatures resistant polymers and oligomers containing the hexafluoroisopropylidene (6F) group. 2,2‐Bis(4‐triflatophenyl)hexafluoropropane (2) undergoes quantitative dinitration at the 3,3′‐positions to yield 2,2‐bis(3‐nitro‐4‐triflatophenyl)hexafluoropropane (3) which ultimately leads to the 3,3′‐diamino‐4,4′‐bis(arylamino) (5) and 3,3′‐diamino‐4,4′‐dihydroxy (8) derivatives which are specifically designed for phenylbenzimidazole, benzimi

ISSN:0360-6376    

DOI:10.1002/pol.1982.170200903

出版商:John Wiley&Sons, Inc.    

年代:1982

数据来源: WILEY

摘要:

Abstractp‐Styryldiphenylphosphine was grafted onto polypropylene by γ‐radiation. However, olefinic phosphines in general do not readily undergo such grafting. Among the many other olefinic phosphines examined only 1‐(4‐diphenylphosphinophenyl)‐prop‐1‐ene and vinyldiphenylphosphine were grafted successfully and both had low grafting yields. The optimum conditions for grafting involve low dose rates and high total doses of γ‐radiation in dimethylsulfoxide as solvent. This grafting is sensitive to impurities and inhomogeneity in the product readily results, especially at high grafting yields. Oxygen must be rigorously excluded if oxidation of grafted phosphorus(III) to phosphorus (V) is to be avoided. Phosphine oxides can be reduced to phosphines when grafted to the polymer with trichlorosilane. Mass spectrometry has shown that more than one olefinic phosphine binds to a single site in the polymer. Solid‐state, high‐resolution31P‐NMR is a valuable technique for characterizing the grafted polymer. The preparation and characterization of the following hitherto unreported phosphines is described:In addition, the precursor halidesnone of which has been reported, were pre

ISSN:0360-6376    

DOI:10.1002/pol.1982.170200904

出版商:John Wiley&Sons, Inc.    

年代:1982

数据来源: WILEY

摘要:

AbstractKinetics of the polymerization of methyl methacrylate by an acidic peroxo salt like potassium monopersulfate catalyzed by Co(II) have been investigated in aqueous medium, over the range of 35–50°C. The rates of polymerization (Rp) have been studied at various concentrations of monomer and initiator. The efficiencies of various metal salts in catalyzing the polymerization have been evaluated from the observed value ofRp. The effects of catalyst (CoSO4), initiator, monomer, and various concentrations of FeCl3onRpand percentage conversion have been studied. The end groups of the recovered polymers have been studied using standard methods. From the observed end groups and kinetic results, a reaction scheme has been proposed involving initiation bySO4· or OH· radicals, generated by the interaction of the initiator with cobalt sulfate and termination of the polymer chains by mutual combina

ISSN:0360-6376    

DOI:10.1002/pol.1982.170200905

出版商:John Wiley&Sons, Inc.    

年代:1982

数据来源: WILEY

摘要:

AbstractA procedure based on diffuse reflectance spectroscopy was developed to determine the UV screening effect of a benzotriazole light stabilizer in wool fabric. Expressions that enable the protective effect of the stabilizer to be calculated directly from reflectance data were derived. The dependence of the screening effect on additive concentration was deduced from measurements of fabric reflectivity in the wavelength range of 300–400 nm. Two reflectometers with quite different optical geometries were used to measure the reflectance spectra and the merits of the two systems are discussed. A theoretical expression for the optical screening phenomenon in highly scattering materials was evaluated for substrates of different reflectivity and the general implications of this relationship are considere

ISSN:0360-6376    

DOI:10.1002/pol.1982.170200906

出版商:John Wiley&Sons, Inc.    

年代:1982

数据来源: WILEY

摘要:

AbstractA study was made of the photoprotective effect of a sulfonated hydroxyphenylbenzotriazole light stabilizer in wool fabric. Investigations of the absorption, luminescence quenching, and photostabilizing properties of the benzotriazole showed that optical screening is the key mode of operation. Excited‐state quenching is of little practical importance. The protective effect of the stabilizer is strongly dependent on the exposure conditions. There is a good correlation between UV screening ability and photoprotection at wavelengths near 300 nm where the fiber has maximum photosensitivity but the correlation in the spectral region of 314–390 nm is poor. The failure of the benzotriazole to provide good protection in the near‐UV region of the spectrum is attributed mainly to the sensitizing action of a small number of fluorescent molecules of the stabilizer, the internal hydrogen bond of which has been disrupted by the influence of the polar environment of the subs

ISSN:0360-6376    

DOI:10.1002/pol.1982.170200907

出版商:John Wiley&Sons, Inc.    

年代:1982

数据来源: WILEY

摘要:

AbstractThe reactions between AlEt3and the modifiers, promoters, and coactivators of a typical magnesium‐chloride‐supported, high‐activity propylene polymerization catalyst were studied. Infrared, MS analysis of the gas evolved, and GC–MS of the hydrolysis products for the reaction between AlEt3andp‐cresol showed rapid and quantitative reactions withp‐cresol either in the support or solution. The reaction products from AlEt3and esters were hydrolyzed, acidified, and dehydrated. The resulting carbonyl and olefinic compounds were identified by GC–MS. Proton and carbon nuclear magnetic resonance (NMR) techniques were also used to study these reactions. The expected intermediates were found in the PMR and CMR spectra. The mechanisms of reactions were proposed. The results of this study showed that when AlEt3and esters are used as coactivators reaction products that can significantly influence the performance of the cataly

ISSN:0360-6376    

DOI:10.1002/pol.1982.170200908

出版商:John Wiley&Sons, Inc.    

年代:1982

数据来源: WILEY

摘要:

AbstractElectron paramagnetic resonance (EPR) was used to study a MgCl2‐supported, high‐mileage olefin polymerization catalyst. Anhydrous Toho MgCl2was the starting material. Treatment with HCl at an elevated temperature, ethyl benzoate by ball‐milling,p‐cresol, AlEt3, and TiCl4produced a catalyst that contained a single EPR observable Ti+3species A, which was strongly attached to the catalyst surface, had a D3hsymmetry, and no other Ti+3ion in an immediately adjacent site. Species A constitutes only 20% of all the trivalent titaniums; the remainder is EPR‐silent and may be attributed to those Ti+3ions that have adjacent sites occupied by one or more Ti+3ions. Activation with preformed AlEt3/methyl‐p‐toluate complexes produced a single Ti+3species (C) with rhombic symmetry and displaying27Al superhyperfin splitting which has attributes for a stereospecific active site. This species is unstable under polymerization conditions and is transformed to another species with axial symmetry and solubilization. Both processes could lead to catalyst deactivation and loss of stereospecificity. Catalysts activated by AlEt3and methyl‐p‐toluate separately in various sequential orders produced a multitude of EPR‐observable Ti+3species with varying degrees of motional freedom deemed detrimental to stereospecific polymeri

ISSN:0360-6376    

DOI:10.1002/pol.1982.170200909

出版商:John Wiley&Sons, Inc.    

年代:1982

数据来源: WILEY

摘要:

AbstractBiuret oligomers and polymers from primary aliphatic amines and aromatic or aliphatic diisocyanates have been synthesized. To demonstrate the feasibility of the synthesis of polybiurets, aliphatic primary amines withn‐propyl,n‐hexyl,n‐octyl, andn‐dodecyl groups have been incorporated. For the synthesis of biuret oligomers of biologically active primary aliphatic amines [8‐(4‐amino‐1‐methylbutylamino)‐6‐methoxyquinoline] (primaquine) and adamantanamine were selected. Primaquine was also incorporated into polyepichlorohydrin by nucleophilic substitution of the chlorine of the chloromethyl group by the primary aliphatic amino group of primaquine. The structure of the biuret polymers was established by elemental analysis, and by infrared1H‐ and13C‐NMR spectroscopic characterization. Several attempts to use primaquine as a diamine for the formation of condensation polymers, including reaction of primaquine with sebacoyl chloride (to form polyamides), or with diisocyanates (to form polyu

ISSN:0360-6376    

DOI:10.1002/pol.1982.170200910

出版商:John Wiley&Sons, Inc.    

年代:1982

数据来源: WILEY