ISSN:0025-116X    

DOI:10.1002/macp.1974.021750101

出版商:Hüthig&Wepf Verlag    

年代:1974

数据来源: WILEY

摘要:

AbstractTransesterifications ofatacticandisotacticpoly(methyl acrylate) with optically active alcohols such as (S)‐2‐methyl‐butanol, D‐borneol and L‐menthol were carried out in toluene at 100°C usingp‐toluenesulfonic acid as catalyst to obtain optically active polymers. In addition a relationship between the conformation and the optical behaviour of the transesterified poly(methyl acrylate) was investigated. The specific rotation of the transesterifiedatacticpoly(methyl acrylate) increased linearly with increasing introduced optically active groups at the lateral chain, in contrast to that of theisotacticpoly(methyl acrylate) which increased nonlinearly with increasing introduced asymmetric groups. Since the specific rotations of the transesterified polymers depend on these tacticities the conclusion was drawn that the optical activity is caused not only by the asymmetric group in the lateral chain but also by molecular dissymmetry in the pri

ISSN:0025-116X    

DOI:10.1002/macp.1974.021750102

出版商:Hüthig&Wepf Verlag    

年代:1974

数据来源: WILEY

摘要:

AbstractThe moisture absorbency (m) and the syntheses of polyamides by condensation oftrans‐2,5‐dimethylpiperazine and/or hexamethylenediamine with adipic acid and/or benzene‐1,3,5‐tricarboxylic (trimesic) acid were studied. It was found that a highm‐value of 24,2 was obtained in the case of the ratio (2/3 trimesic acid)/adipic acid = 0,1 and a decrease ofmwith an increasing mole ratio oftrans‐2,5‐dimethylpiperazine/hexamet

ISSN:0025-116X    

DOI:10.1002/macp.1974.021750103

出版商:Hüthig&Wepf Verlag    

年代:1974

数据来源: WILEY

摘要:

Abstract2,4‐Diphenyl‐6‐(3‐maleoyliminophenyl)‐3,4‐dihydro‐s‐tetrazin‐1(2H)‐yl (6) was synthesized and anionically polymerized with a catalytic amount of sodium 1,4‐dihydro‐1,4‐naphthalenediide, with a conversion up to 96%. The polymer was a dark green powder with a content of radical groups of about 58% (based on unit mol), and its relative molecular mass was about 4 800, correspond

ISSN:0025-116X    

DOI:10.1002/macp.1974.021750104

出版商:Hüthig&Wepf Verlag    

年代:1974

数据来源: WILEY

摘要:

AbstractPoly(vinyl alcohol)s derived from poly(vinyl trifluoroacetate), obtained by free radical polymerization of vinyl trifluoroacetate in various kinds of solvents at temperatures between 60 and −40°C, are reacted with iodine in aqueous solution, and UV‐spectra of the solutions were measured after the reaction. The absorption maximum in the UV‐spectrum appears at 600 nm for the polymers obtained in ketones, alkanes, and esters or at 590 nm in aldehydes. The absorbance of the maximum increases with increasing syndiotacticity up to a content of syndiotactic diads ofXs≈︁ 55,5–58,5% or of triads ofXss≈︁ 34,2–39,3%, then it passes through a maximum value and decreases with increasingXsorXss. It is considered that the increases is due to the stereoregularity of the PVA molecules and that the decrease is due to the formation of mic

ISSN:0025-116X    

DOI:10.1002/macp.1974.021750105

出版商:Hüthig&Wepf Verlag    

年代:1974

数据来源: WILEY

摘要:

Abstract2‐Bromoethoxyphenoxyphosphoryl methacrylate (5) was synthesized by the reaction of 2‐bromoethyl phenylchlorophosphonate (3) with silver methacrylate and then polymerized by a radical initiator. The resulting polymer was soluble in DMF, but insoluble in other organic solvents. The hydrolysis of the polymer with sulfuric acid led to the corresponding poly(methacrylic acid) with a molecular weight ofMn=4,4·105(Pn=5,1·103).5was copolymerized with acrylonitrile and the monomer reactivity ratio was determined:r1= 2,20,r2

ISSN:0025-116X    

DOI:10.1002/macp.1974.021750106

出版商:Hüthig&Wepf Verlag    

年代:1974

数据来源: WILEY

摘要:

AbstractCationic model compounds of polynucleotide,i.e., poly{1‐[2‐(adenin‐9‐yl)ethyl]‐4‐pyridinioethylene chloride} (1), poly{1‐[2‐(thymin‐1‐yl)ethyl]‐4‐pyridinioethylene chloride} (2), and poly{1‐[2‐(theophillin‐7‐yl)ethyl]‐4‐pyridinioethylene chloride} (3), were synthesized by the MENSCHUTKIN reaction of poly(4‐pyridylethylene) with 9‐(2‐chloroethyl)adenine, 1‐(2‐chloroethyl)thymine and 7‐(2‐chloroethyl)theophylline.The interactions between the model compounds and polynucleotides and between the model compounds themselves were studied by spectroscopy. The apparent hypochromicity was about 20% for the mixture of1‐Poly A, 15% for that of1‐DNA and 11% for the1–3mixture. The systems1–2and2–3showed rather small hypochromicities, being 8 and 6%, respectively. The hydrogen bond formation between complimentary bases is not a main factor in the intermolecular interactions in the present cases, but the hydrophobic interactions are suggested to be overwhelming. The UV absorbance of1–2or2–3mixtures decreased with increasing temperature

ISSN:0025-116X    

DOI:10.1002/macp.1974.021750107

出版商:Hüthig&Wepf Verlag    

年代:1974

数据来源: WILEY

摘要:

AbstractPoly(N‐vinylcarbazole) and its monomeric analog,i.e.,N‐ethylcarbazole, act as donors in charge‐transfer complex formations with such electron acceptors as 2,3,5,6‐tetracyano‐1,4‐dimethylene‐2,5‐cyclohexadien‐1,4‐diylidene, tetracyanoethylene and 2,4,5,7‐tetranitro‐9‐fluorenone. The formation constants of the charge‐transfer complex ofN‐ethylcarbazole with the electron acceptors are higher than those of poly(N‐vinylcarbazole) with the same electron acceptors. In order to clarify the polymer effect on these formation constants, poly(N‐vinyl carbazole)s, prepared by two types of polymerizations, are fractionated using a gel permeation chromatography technique, and the fractionated polymers are used for the measurements of the formation constants of the charge‐transfer complexes with various sorts of electron acceptors. The relation between charge‐transfer complex formation and molecular weight of the polymer is discussed in terms of the formation cons

ISSN:0025-116X    

DOI:10.1002/macp.1974.021750108

出版商:Hüthig&Wepf Verlag    

年代:1974

数据来源: WILEY

摘要:

AbstractThe dissociation constants (pKb) ofN‐(hydroxymethyl)‐2,4,6‐triamino‐s‐triazines (methylol melamines) (1) andN‐methoxymethyl‐2,4,6‐triamino‐s‐triazines (methylated methylol melamines) (2) were determined by electrometric titration. The pKbvalues of1, having an average degree of formaldehyde substitution ofn3 increased with decreasing pH. Thus, a different behavior of protonation between1and2was observed, and the causes were discussed. Linear correlations were found between

ISSN:0025-116X    

DOI:10.1002/macp.1974.021750109

出版商:Hüthig&Wepf Verlag    

年代:1974

数据来源: WILEY

摘要:

AbstractIn order to clarify the mechanism of catalysis of polyvinylamine‐copper(II) chelates on the initiation of vinyl polymerizations, stability constants of these chelates were measured by applying a modification of BJERRUM'S method, and each concentration of the chemical species was estimated on the basis of the chelate theory. From these results, the activity of the polyvinylamine‐copper(II) chelates for the polymerization of acrylonitrile and methyl methacrylate at different pH values was discus

ISSN:0025-116X    

DOI:10.1002/macp.1974.021750110

出版商:Hüthig&Wepf Verlag    

年代:1974

数据来源: WILEY