摘要:

AbstractPoly[thio(thiocarbonyl)oxy‐1,4‐cyclohexyleneoxy(thiocarbonyl)thiomethylene‐1,4‐phenylenemethylene] (4) was obtained from 4‐bromomethylbenzyl bromide (1), dipotassium 1,4‐cyclohexanediolate (2) and carbon disulfide at low temperature by using 1,4,7,10,13,16‐hexaoxacyclooctadecane as catalyst. At high temperatures, poly[oxy‐1,4‐ cyclohexyleneoxymethylene‐1,4‐phenylenemethylene] (8) was obtained from the reaction between1and2, however. Mechanisms are propose

ISSN:0025-116X    

DOI:10.1002/macp.1980.021810501

出版商:Hüthig&Wepf Verlag    

年代:1980

数据来源: WILEY

摘要:

AbstractPolyhydroxyethers were synthesized from monoalkali metal salts of diphenols and 1‐halo‐2,3‐epoxyalkanes in a one‐step reaction in dipolar, aprotic solvents as reaction media. They were also synthesized from alkali metal salts of diphenols, dihalobenzoid compounds with electron‐withdrawing groups between benzene rings and 1‐halo‐2,3‐epoxyalkanes by a tw

ISSN:0025-116X    

DOI:10.1002/macp.1980.021810502

出版商:Hüthig&Wepf Verlag    

年代:1980

数据来源: WILEY

摘要:

AbstractThe copolymerization of elemental sulfur (2) with 2,2‐dimethylthiirane (1), initiated with sodium thiophenolate in benzene solution was studied. By1H NMR and laser Raman spectroscopy of the resulting copolymers3it could be shown that true copolymers with short polysulfide chains are formed and that starting with a sufficiently large ratio of2/1diads of1are absen

ISSN:0025-116X    

DOI:10.1002/macp.1980.021810503

出版商:Hüthig&Wepf Verlag    

年代:1980

数据来源: WILEY

摘要:

AbstractThe oxidation of guaiacol by the Fe(III)‐oaPc/H2O2system is studied by using a stopped flow spectrophotometer. The maximum rate of oxidation reaction by this system amounts to about 1000 times that in the absence of H2O2. The kinetic investigation indicates that the reaction can be regarded as “an ordered two‐substrates reaction” and that the oxidation reaction proceeds according to the peroxidase‐like mechanism. The reaction is inhibited by adding cyanide. The structure of oxidation products is also discussed. The catalytic action of Fe(III)‐oaPc in the presence of various polyelectrolytes such as poly(vinylamine) is also investigated, varying the pH values, and the environmental effect of the polymers in their catalytic behavior i

ISSN:0025-116X    

DOI:10.1002/macp.1980.021810504

出版商:Hüthig&Wepf Verlag    

年代:1980

数据来源: WILEY

摘要:

AbstractThe effect of β‐carotene on the photochemical reactivity of anthracene in hexane solution was investigated. A kinetic scheme of photochemical and photophysical processes occurring in the system irradiated with light at λ = 365 nm is proposed. The rate constants of physical quenching process and chemical reaction between β‐carotene and singlet oxygen molecule were dete

ISSN:0025-116X    

DOI:10.1002/macp.1980.021810505

出版商:Hüthig&Wepf Verlag    

年代:1980

数据来源: WILEY

摘要:

AbstractThe inhibiting effect of β‐carotene on anthracene sensitized photooxidation of polystyrene was observed and a kinetic scheme of the photophysical and photochemical processes in the system was proposed. The rate constants of several processes occurring in the system were evaluated. The indexes of reactivity for anthracene and β‐carotene in polystyrene were deter

ISSN:0025-116X    

DOI:10.1002/macp.1980.021810506

出版商:Hüthig&Wepf Verlag    

年代:1980

数据来源: WILEY

摘要:

AbstractAdducts ofcis‐1,4‐polybutadiene with both benzene‐ and toluenesulfenyl chlorides were conveniently oxidised in a second stage modification withm‐chloroperbenzoic acid to yield novel sulfone thermoplastic polymers. These have higher glass transition temperatures and are more thermostable than the parent

ISSN:0025-116X    

DOI:10.1002/macp.1980.021810507

出版商:Hüthig&Wepf Verlag    

年代:1980

数据来源: WILEY

摘要:

AbstractThe nature of interactions between polyethylene and a wetting solute was analyzed to know if the interface can be characterized by the expression of the sticking work or if other phenomena than adhesion and wetting must be taken into account. In this way, the sorption isotherms, the molar interaction heats and the cinetic characters of the sorption gave informations about the possible importance of a diffusion of the solvent. Two types of systems were investigated: polyethylene/alkanes and polyethylene/alcohols. The formation of almost homogeneous solutions or, on the contrary, of aggregates is discussed.

ISSN:0025-116X    

DOI:10.1002/macp.1980.021810508

出版商:Hüthig&Wepf Verlag    

年代:1980

数据来源: WILEY

摘要:

AbstractChlorination under mild conditions of suspensions of polyethylene single crystals demonstrated that a selective attack on the fold surface takes place. Two polyethylene molecular weight fractions (Mn= 47000 andMn= 150 000) were used and single crystals were grown isothermally fromp‐xylene at 88°C. The chlorine content was changed from 4 wt.‐% to 30 wt.‐% and to this level no evidence for crystal attack and loss of crystallinity was found. The melting temperatures of chlorinated single crystals decrease with increasing chlorination up to about 15 wt.‐% chlorine content and then stay constant for higher chlorine contents. Moreover, the heat of melting of the chlorinated single crystals is constant and is independent of the chlorine content up to 25 wt.‐%. These results are compared with those of samples of chlorinated polyethylene recrystallized from solution and fro

ISSN:0025-116X    

DOI:10.1002/macp.1980.021810509

出版商:Hüthig&Wepf Verlag    

年代:1980

数据来源: WILEY

摘要:

AbstractIn this paper, the assignment of the1H and13C NMR spectra of poly(galacturonic acid)s is proposed; the4C1chair conformation of the monomeric unit in poly(galacturonic acid) is confirmed and the composition of the anomeric mixture at the reducing end (α−D)/(β−D) = 35 : 65 mol/mol independent of the degree of polymerization DP (2 ⩽ DP ⩽ 5) is given. It is demonstrated on oligomers that both13C and1H chemical shifts and coupling constants are nearly unaffected by exchanging Na counterions with Ca; the osmotic coefficient of Ca depends on the DP just as predicted by an electrostatic mechanism. The intrinsic viscosity of the polymer increases and the intensity of13C NMR signals decreases suddenly for 0,3 equivalents Ca2+per carboxylic site. These results confirm a multichain association followed by a rigid gel formation; the crosslink is proposed to correspond to a cooperative “egg‐box” mechanism on chain segments randomly distrib

ISSN:0025-116X    

DOI:10.1002/macp.1980.021810510

出版商:Hüthig&Wepf Verlag    

年代:1980

数据来源: WILEY