Viscosity – Molecular Weight Relationships and Unperturbed Dimensions of Linear Chain Molecules

In 1954 a patent by Matlack [1] and shortly thereafter a paper by Breslow, Hulse, and Matlack [2] described that acrylamide readily polymerizes to fairly high molecular weight poly(β-alanine) (nylon 3) in the presence of anionic initiators such as t-BuONa.

Hydrogen Transfer Polymerization with Anionic Catalysts and the Problem of Anionic Isomerization Polymerization

Factors affecting the nascent structure and morphology of polyethylene obtained by heterogeneous Ziegler-Natta catalysts: 1. Polymerization kinetics

The thermodynamics, kinetics, and mechanism of the anionic polymerization of a number of acrylamide monomers has been studied with the use of isothermal and scanning calorimetry, liquid chromatography, 1H NMR and IR spectroscopy, mass spectrometry, and chemical analysis of functional groups. It has been demonstrated that the polymerization system shows the living character and the interchain exchange reactions are absent. It has been shown that N,N-diethanolacrylamide and N,N-diethanol(meth)acrylamide are uninvolved in anionic polymerization. The causes of this phenomenon have been ascertained. The products of the anionic polymerization of acrylamides are hyperbranched copolymers containing heterochain and carbochain fragments. Macromolecules contain end amide and acrylamide groups; in some macromolecules, end tert-butoxide groups of the used polymerization initiator are detected. For the products of the anionic polymerization of the acrylamide monomers under study, the temperatures of glass transition and melting have been measured.

Kinetics and mechanism of the anionic polymerization of acrylamide monomers

Short-range interactions between chain units of random copolymers in solution may be influenced by the characters of the pendant side groupes or, more precisely, by the dipole moment of the substituent. In those experiments the steric factor was derived for a random copolymer composed of methyl methacrylate and acrylonitrile from the relation between the limiting viscosity number and the molecular weight. Mark-Houwink relations were obtained in N,N′-dimethylformamide (DMF) and in methyl ethyl ketone (MEK) at 30°C for the copolymer containing 0.48 mol fraction of acrylonitrile, and for polymethyl methacrylate (PMMA) for the sake of comparison:[η]=4.61×10−4M0.65 for the copolymer in DMF[η]=1.70×10−4M0.65 for PMMA in DMF[η]=1.26×10−3M0.52 for the copolymer in MEKWith the Stockmayer-Fixman expression, these correlations become, respectively:[η]=213×10−5M1⁄2+12.4×10−7M[η]=78.2×10−5M1⁄2+5.05×10−7M[η]=163×10−5M1⁄2+1.05×10−7MThe unperturbed mean square end-to-end distance, ⟨L2⟩0, determined from the first term of...

Solution Properties of the Methyl Methacrylate-Acrylonitrile Copolymer

Um den Einflus der Polymerisationstemperatur auf die Molekulformation des Polyacrylnitrils zu untersuchen, werden zwei Praparate bei zwei verschiedenen Temperaturen unter Verwendung eines Redoxsystems hergestellt. Die Molekulargewichte von sieben Fraktionen des bei −30°C hergestellten Polymerisates („T„-Reihe) und von sechs Fraktionen des bei +60°C gewonnenen („S„-Reihe) werden nach dem Ultrazentrifugen-Verfahren von ARCHIBALD bestimmt.



Zwischen der Viskositatszahl in Dimethylformamid (DMF) und dem Molekulargewicht gelten folgende Beziehungen: 






Die Viskositatsgleichung fur die „S„-Reihe stimmt mit der von CLELAND und STOCKMAYER sehr gut uberein.



Die Mesdaten werden mit Hilfe der neuen Viskositatstheorie von STOCKMAYER und FIXMAN analysiert, um die ungestorten Knaueldimensionen der beiden polymerhomologen Reihen miteinander zu vergleichen. Die dieser Theorie entsprechende Form der [η]-M-Beziehung lautet fur die „S„-Reihe: 








Es wird gefunden, das die ungestorte Knaueldimension der „S„-Reihe um etwa 10% kleiner ist als die der „T„-Reihe. Der sterische Faktor σ, der als Verhaltnis der ungestorten Knaueldimension zu der bei freier Drehbarkeit zu erwartenden definiert wird, liegt bei 2,10 fur die „S„-Reihe und bei 2,30 fur die „T„-Reihe. Dieser Tatsache wird entnommen, das der syndiotaktische Anteil des Polyacrylnitrils durch Erniedrigung der Polymerisationstemperatur vergrosert wird.



In order to study the influences of polymerization temperature upon the molecular conformation of polyacrylonitrile, two types of samples are prepared at two different temperatures using a redox system. By employing the ARCHIBALD ultracentrifugal procedure the molecular weight determination is made for seven fractions from a sample polymerized at −30°C. (“T”-series) and for six ones from that obtained a t +60°C. (“S”-series).



Between the intrinsic viscosity in dimethyl formamide (DMF) and the molecular weight the following relations are found: 






The viscosity equation for the “5”-series is in good agreement with that of CLELAND and STOCKMAYER.



These results are analysed with aid of the recent viscosity theory of STOCKCMAYER and FIXMAN to evaluate the unperturbed dimension of these two homologous series. The [η]- M-relation for the “S”-series in the STOCKMAYER-FIXMAN form is: 








The unperturbed dimension of the „S”-series is found to be smaller than that of the “T”-series. The steric factor σ, defined as the ratio of unperturbed dimension to that corresponding to the free rotation, is about 2.10 and 2.30 for the “S”- and “T”-series, respectively. This leads to the conclusion that the syndiotactic part in the chain of polyacrylonitrile will be increased by a lowering of the temperature of polymerization.

Die ungestörte knäueldimension von polyacrylnitril unter berücksichtigung des einflusses der polymerisationstemperatur

Sorbamide and β-vinylacrylamide were polymerized using tert-BuONa and n-BuLi as catalysts. The resulting polymers were analysed by infrared spectroscopy and hydrolyzed to subject to paper chromatography. The hydrolysis products were primarily δ-amino acids. Thus it was concluded that the polymerization proceeded mainly by the hydrogen transfer mechanism, leading to poly-δ-amides.



Poly-β-vinylacrylamides obtained by basic catalysts were insoluble, whereas polysorbamides were soluble at first but became insoluble on standing under air. Both these polyamides were amorphous.



Sorbinsaureamid und β-Vinylacrylsaureamid wurden mit (CH3)3CONa und CH3(CH2)2CH2ONa als Katalysatoren polymerisiert. Von den Polymeren wurden Infrarotspektren aufgenommen. Die Polymeren wurden hydrobysiert, die Hydrolysenprodukte papierchromatographisch untersucht und gezeigt, das sle in erster Linie aus δ-Aminosauren bestehen. Daraus wurde geschlossen, das die Polymerisationen hauptsachlich uber den Mechanismus der Wasserstoffubertragung verlaufen, der zur Bildung von Poly-δ-amiden fuhrt.



Die Poly-β-vinylacrylsaureamide waren unloslich, wahrend die Polysorbinsaureamide sich zunachst losten, jedoch beim Stehen an der Luft unloslich wurden. Beide Potymere waren amorph.

T. Matsuo

Papers

Die ungestörte knäueldimension von polyacrylnitril unter berücksichtigung des einflusses der polymerisationstemperatur

Base‐catalyzed polymerization of sorbamide and β‐vinylacrylamide