摘要:

AbstractThe structure and thermal degradation behaviour of polyesters from terephthalic and/or succinic acid and hydroquinone were investigated by pyrolysis mass spectrometry. Poly(oxysuccinyloxy‐1,4‐phenylene) (2) undergoes cleavage of the ester bond (Eq. (vii)) as a very selective pyrolysis mechanism at 310°C, whereas the thermally more stable poly(oxyterephthaloyloxy‐1,4‐phenylene) (1) starts to degrade above 400°C and yields pyrolysis products with phenyl (Eq. (iv)),p‐hydroxyphenyl (Eq. (iii)), benzoyl (Eq. (iiv)) and carboxylic end groups. A calibration curve of the intensities of monomer specific fragments, obtained from pyrolysis mass spectra of polyesters from terephthalic acid, succinic acid, and hydroquinone provides the exact determination of their c

ISSN:0025-116X    

DOI:10.1002/macp.1978.021791201

出版商:Hüthig&Wepf Verlag    

年代:1978

数据来源: WILEY

摘要:

AbstractPolymerization of free α‐amino acids with a pair of reagents–an oxidizing agent (iodine) and a reducing agent (phosphonic acid esters)–was achieved in organic medium in the presence of pyridine or imidazole. A standard procedure leading to optically pure polypeptides with degrees of polymerization up to 50 could be established. Polymeric material was also obtained with a dipeptide as monomer. Some preliminary polymerizations with polyfunctional reagents such as poly(4‐vinylpyridine), cyclodiphosphites, or polyphosphites were p

ISSN:0025-116X    

DOI:10.1002/macp.1978.021791202

出版商:Hüthig&Wepf Verlag    

年代:1978

数据来源: WILEY

摘要:

AbstractThe copolymerization of carbon dioxide and epoxypropane was investigated at 80°C in dioxane by using cobalt(II) acetate as catalyst in the presence of acetic acid. The addition of acetic acid hardly diminishes the copolymer yield, but the number average molecular weight of the copolymer decreases in proportion to the concentration of acetic acid. The1H NMR spectrum of the copolymer displays a very strong peak due to the methyl protons attached to an ester carbonyl group (OCOCH3). From these results it has been concluded that acetic acid causes a transfer reaction which leads to acetoxy end groups (cf. Eq. (14) below). Some other carboxylic acids, such as C6H5COOH, ClH2CCOOH, Cl2HCCOOH etc., were found to cause similar transfer reaction

ISSN:0025-116X    

DOI:10.1002/macp.1978.021791203

出版商:Hüthig&Wepf Verlag    

年代:1978

数据来源: WILEY

摘要:

AbstractWater soluble azo compounds of the structure1a, b, 2a, b, 3, 4, and5decompose, depending on the substitution of the aromatic ring, in water already at room temperature. Therefore, they are useful initiators for solution and emulsion polymerisations in this temperature region. Reactions competing with thermolysis, as the formation of a hydrazone (pH>8) and ionic reactions with suitable reagents (phenols) are described.

ISSN:0025-116X    

DOI:10.1002/macp.1978.021791204

出版商:Hüthig&Wepf Verlag    

年代:1978

数据来源: WILEY

摘要:

AbstractPoly(cis‐3,4‐dihydroxytetrahydropyran‐6,2‐diyloxymethylene) (5a), a new polysaccharide‐type polymer having the same backbone structure as that of natural dextran but differing in the number and configuration of hydroxylic groups in the repeating unit, was successfully prepared by osmium tetroxide oxidation of poly(5,6‐dihydro‐2H‐pyran‐6,2‐diyloxymethylene) under mild conditions. The structure of5awas established from1H and13C NMR analyses of5aand its methylated product5b. Water absorption of5awas measured at different humidities ranging from 43 to 97% at 20°C and compared with those of relevant polymers having analogous structures. The polymer5awas found to be degrad

ISSN:0025-116X    

DOI:10.1002/macp.1978.021791205

出版商:Hüthig&Wepf Verlag    

年代:1978

数据来源: WILEY

摘要:

AbstractA copolymer composition equation is derived for the cyclo‐copolymerization of a 1,6‐diene with a monoolefin that do not homopolymerize. The theory is applied to the free radical copolymerization of diallyl ether (DAE) with maleic anhydride (MA) and to that of DAE with fumaronitrile (FN). Both systems fall in the special case where there are no unreacted CC bonds left in the copolymer. The copolymer compositions are between 1:1 and 1:2 (=[diene]:[monoolefin]) over a wide range of monomer feed composition. The reactivity ratios obtained from the equation indicate that for the DAE/MA system, the intramolecular cyclization of the uncyclized DAE radical is 2,9 times more effective than the addition of MA monomer to the uncyclized DAE radical, and that for the system of DAE/FN, the intramolecular cyclization of DAE radical is 6,7 times more effective than the addition of FN mo

ISSN:0025-116X    

DOI:10.1002/macp.1978.021791206

出版商:Hüthig&Wepf Verlag    

年代:1978

数据来源: WILEY

摘要:

AbstractThe synthesis and polymerization of 2‐cyanoethylN‐vinylcarbamate (3b) and of the corresponding 2‐trimethylsilylethyl isomer3care reported. The homopolymers4band4c, derived from3band3c, could be deblocked under mild conditions (ethanolamine for4band trifluoroacetic acid or tetraethylammonium fluoride for4c) with essentially 100% unmasking of the amino function. Treatment of such unmasked amino groups in a copolymer derived fromN‐vinyl‐2‐pyrrolidone and3bwith 4‐{4‐[bis(2‐chloroethyl)amino]phenyl}butyryl chloride (13) (chlorambucil chloride) gave the corresponding amide, a potential antitumor agent. Kinetic studies showed that fluoride ion cleavage of poly(2‐trimethylsilylethylN‐vinylcarbamate) occurred at rates comparable to those observed for the low molecular weight analog 2‐trimethylsilylethylN

ISSN:0025-116X    

DOI:10.1002/macp.1978.021791207

出版商:Hüthig&Wepf Verlag    

年代:1978

数据来源: WILEY

摘要:

AbstractThe copolymerization in inverted emulsion of acrolein withN‐vinylpyrrolidone is described. The resulting copolymer, called VINAC, was obtained as spherical hydrophilic beads. VINAC was successfully used to immobilize trypsin, presumably via imine bond formation. The water‐insoluble enzyme derivatives thus obtained have a total enzymatic activity which can reach the value of 29% in certain ca

ISSN:0025-116X    

DOI:10.1002/macp.1978.021791208

出版商:Hüthig&Wepf Verlag    

年代:1978

数据来源: WILEY

摘要:

Abstract60 MHz undecoupled α‐, 90 MHz undecoupled β‐, and 90 MHz decoupled α‐ and β‐proton spectra were measured for seven poly(vinyl chloride) samples, four of these being commercial type polymers, the others were prepared at +75°C, +5°C and −30°C. The results were used to assess the preferred approach to the determination of tacticity. The reproducibility of the values from different solutions of a given polymer is significantly worse than that between a series of runs on a particular solution, showing that sampling errors are larger than those from instrumental sources. Although the 60 MHz spectra were found to be unsatisfactory when interpreted on a first order basis, curve fitting methods, which were similar to those used for the other types of spectra and involved the use of reasonable assumptions for chemical shifts and coupling constants, gave results of comparable precision to those from the two types of decoupled spectra and superior to those from the undecoupled 90 MHz spectra. The preferred approach is to combine the results from α‐ and β‐proton spectra and to examine more than one solution of a given material. The applicability of Bernoullian propagation statistics was assumed in the majority of the curve fitting calculations; in the cases where this was not so the results were used to test this assumption and it

ISSN:0025-116X    

DOI:10.1002/macp.1978.021791209

出版商:Hüthig&Wepf Verlag    

年代:1978

数据来源: WILEY

摘要:

AbstractCalculations of most probable values on the basis of the equationsy=a· x + b · x2,y/x=a+b·xandx=a*+b*·y/xhave been carried out with data from solution viscometry, ebulliometry, and vapor pressure osmometry. The calculations carried out with the method of least squares give different coefficients for the equations taken as a basis. However equal coefficients are obtained with the method of Deming in which the measured data are weighted. Furthermore the so calculated slopes of the equations differ from those determined by the method of least squares whereby the differences depend upon the type of equations and upon the deviation of the measured d

ISSN:0025-116X    

DOI:10.1002/macp.1978.021791210

出版商:Hüthig&Wepf Verlag    

年代:1978

数据来源: WILEY