摘要:

The effect of various cyclic and bicyclic olefins on the yield (rate) and molecular weight of polyisobutene has been investigated. Cyclic olefins were found to be both rate poisons and transfer agents and the corresponding coefficients appear to be a function of ring size. Alkyl and aryl substitution on the ring increases both the poison and transfer coefficients. With bicyclic olefins, norbornene and norbornadiene both show moderate and similar poison coefficients, but only the former exhibits transfer activity. These coefficients have been discussed in terms of the allylic termination hypothesis and the known geometry and steric effects of the various rings studied.

ISSN:0022-233X    

DOI:10.1080/10601326708053750

出版商:Taylor & Francis Group    

年代:1967

数据来源: Taylor

摘要:

The effects of various allyl chlorides and alkyl halides on the overall yield of polymerization and molecular weight of polyisobutene have been investigated and expressed quantitatively by poison and transfer coefficients. The poison and transfer coefficients of halides have been compared with those obtained previously for corresponding hydorcarbons. The poison coefficients of halides and hydrocarbons can be treated formally in a similar manner (1/Wpvs. [X] plots linear for both classes); however, the appropriate transfer coefficients indicate fundamentally dissimilar transfer mechanisms in these systems (1/MWpvs. [X] plots linear for hydrocarbons, whereas 1/MWpvs. [X]1/2plots linear for halides). These results are discussed in terms of the allylic termination mechanism.

ISSN:0022-233X    

DOI:10.1080/10601326708053751

出版商:Taylor & Francis Group    

年代:1967

数据来源: Taylor

摘要:

Der Einfluss von HCI und Chloräthylbenzol auf die Ausbeute und das Molekulargewicht von Polyisobutylen wurde untersucht. Es konnten keine sinnvollen Vergiftungs-und Übetrträgerkoeffizienten abgeleitet werden da HC1 als ausbeuteverbessernder Promotor wirkte und der Einfluss des Chloräthylbenzols sich als sehr komplex erwies. Die Molekulargewichte der Polyisobutylene waren geringer, je grösser die Menge der vorhandenen Halogenverbindungen war. Es wird postuliert, dass HC1 als Promotor und Überträger wirkt.

ISSN:0022-233X    

DOI:10.1080/10601326708053752

出版商:Taylor & Francis Group    

年代:1967

数据来源: Taylor

摘要:

Auf der Grundlage einer vereinfachten ternären Polymerenzusammen-setzungsgleichung wurde ein Rechenprogramm entwickelt, das die Berechnung der notwendigen Monomerendosierung berechnet um ternäre Polymere gegebener Zusammensetzung herzustellen. Aus den berechneten Dosiermengen fër äaquimolare ternäre Polymere wurden die wahrschein-lichsten Produkte berechnet, welche sich unter diesen Bedingungen maximieren werden. Die Ergebnisse zeigen, dass beträchtliche Wechse-wirkungen zwischen den Monomeren unter den Bedingungen der maxi-malen Anderung auftreten und dass Einflüsse dere-Werte die der Q Werte der Monomeren überwiegen.

ISSN:0022-233X    

DOI:10.1080/10601326708053753

出版商:Taylor & Francis Group    

年代:1967

数据来源: Taylor

摘要:

Free radicals induce two principal types of interaction between fluoro-ketones and olefins, both of which lead to polymeric products. Copolym-erization of the fluoroketone through its carbonyl group leads to poly-ethers. Hydrogen abstraction, presumed to be largely intramolecular, also occurs to give highly branched polymers with fluoroalcohol groups at terminal positions on the branches.

ISSN:0022-233X    

DOI:10.1080/10601326708053754

出版商:Taylor & Francis Group    

年代:1967

数据来源: Taylor

摘要:

p-Substituted phenyl vinyl sulfides (PVS) were prepared and their radical polymerizations were investigated dilatometrically to determine some kinetic constants and to deduce the influences of the sulfur atom andp-substituents of PVS. It was found that PVS could be easily homopolymerized by ordinary radical polymerization mechanisms in the presence of 2,2′-azobisisobutyronitrile, contrary to the case of phenyl vinyl ethers, which do not homopolymerize.

ISSN:0022-233X    

DOI:10.1080/10601326708053755

出版商:Taylor & Francis Group    

年代:1967

数据来源: Taylor

摘要:

The cationic polymerizations of styrene under an electric field have been investigated by using boron trifluoride etherate as a catalyst and binary mixtures of toluene, 1,2-dichloroethane, and nitrobenzene of various compositions as the solvent. The polymerization rate of styrene in dichloroethane was tripled in the presence of a rather low-intensity electric field of 0.25 kV/cm. The field-accelerating effects were found to be nil in pure toluene, increasing with increasing dielectric constant of the mixed solvents and, through the maximum value in pure dichloroethane, decreased with further increase in the dielectric constant. This observation might indicate that the ion pair of the growing chain ends is too “firm” to show the field effects in toluene, whereas the degree of dissociation of ion pairs in nitrobenzene is large to such an extent that the application of the electric field can no longer increase the population of free ions. This interpretation is in qualitative agreement with the prediction of the kinetic scheme presented previously. On the other hand, the degrees of polymerization were not influenced by the electric field.

ISSN:0022-233X    

DOI:10.1080/10601326708053756

出版商:Taylor & Francis Group    

年代:1967

数据来源: Taylor

摘要:

Relative reactivity of cyclic ethers, including epoxide, oxetane, tetrahydrofuran, and tetrahydropyran, was evaluated with their basicity and free energy of polymerization. The logarithm of relative reactivity, 1/rn, ofm-membered ring ethers withisubstituents ton-membered ring monomers withjsubstituents can be expressed by a linear combination of the differences in basicity, Δ(pKb)m·i-n·j, and in free energy, Δ(ΔG)m·i-n·j + γ

ISSN:0022-233X    

DOI:10.1080/10601326708053757

出版商:Taylor & Francis Group    

年代:1967

数据来源: Taylor

摘要:

High molecular weight polybenzoxazinones have been prepared by cyclo-polycondensation reaction of 4,4′-diamino-3,3′-biphenyldicarboxylic acid with a variety of aromatic carbonyl compounds using a solution polymerization technique in polyphosphoric acid. From the model reactions of anthranilic acid, and 4,4′-diamino-3,3′-biphenyldicarboxylic acid with benzoyl chloride in polyphosphoric acid, it is established that the cyclopolycondensation proceeds through the formation of an open-chain tractable precursor, polyamic acid of high molecular weight (ninh = 2.66) in the first step, which subsequently undergoes thermal or chemical cyclodehydration along the polymer chain, to yield, in the second step, a fully aromatic polybenz-oxazinone. Polybenzoxazinones thus obtained have excellent thermal stability both in nitrogen and in air.

ISSN:0022-233X    

DOI:10.1080/10601326708053758

出版商:Taylor & Francis Group    

年代:1967

数据来源: Taylor

摘要:

A method is outlined for the calculation of azeotropic compositions in ternary copolymerization. The results of these calculations are consistent with those reported by Tarasov et al. (2), and with those calculated by a recent method developed by L. J. Young of the Dow Chemical Company. Our results are further checked with the calculated monomer/copolymer composition during the predicted azeotropic copolymerizations. It was found, in all cases, that the monomer/copolymer composition stays constant, as expected. A method of graphical extrapolation is introduced for estimating the azeotropic composition when some reactivity ratios are inaccurate.

ISSN:0022-233X    

DOI:10.1080/10601326708053759

出版商:Taylor & Francis Group    

年代:1967

数据来源: Taylor