Polymerization Of E-caprolactam Research Articles

Some remarks on the condensation stage in hydrolytic ε-caprolactam polymerization

The condensation step of the hydrolytic caprolactam polymerization, in the molten state and batch processes, has been studied. Runs effected in the presence or in the absence of stirring have been compared. The relation between the viscosity of the polymer and the condensation time has a sinusoidal shape in the absence of stirring. The oscillations tend to flatten if the polymerization is carried out in the presence of a chain regulator. This behaviour seems to be due only to condensation reactions and not transamidation.

The polymerization of ε-caprolactum—III. Initiation by tin compounds

The polymerization of ε-caprolactam initiated by weak acids and bases has been reported previously.( 1,2) To extend these observations to Lewis acids, a variety of compounds of tin (II) and (IV) have been examined as possible initiates. The following compounds have been found to be effective: stannic chloride, stannous chloride, stannous octate. Other compounds including stannic fluoride, bromide and iodide are unstable under the reaction conditions. All tin compounds appear to decompose in molten caprolactam and to cause marked discoloration of the resulting polymer. In general, they are unsuitable as initiators.

Some effects of cocatalyst structure on the anionic polymerization of ϵ‐caprolactam. II.

AbstractA study of the effect of catalyst (base) concentration and N‐acylcaprolactam cocatalyst size and substitution on the fast anionic polymerization of caprolactam indicated that a steric effect due to cocatalyst size exists, and perhaps an electronic effect due to cocatalyst substitution was noted. The rate of polymerization, degree of polymerization, and yield of polymer are related to these effects. It was also noted that at high base concentrations, the rate and degree of polymerization along with the product yields all decrease. These latter observations suggest that reinterpretation of some of the reaction mechanism data may be important if polymer degradation is not an appreciable factor during the reaction.

Anionic polymerization of ε-caprolactam in the presence of isocyanates as activators

Anionic polymerization of ε-caprolactam in the presence of isocyanates as activators

Polymerization of ε-caprolactam in the presence of carboxylic acid hydrazides

Polymerization of ε-caprolactam in the presence of carboxylic acid hydrazides

Heterogeneous polymerization of ϵ-caprolactam

The ϵ-caprolactam polymerization below the polymer melting point (180°) is described. The influence of the concentration of the catalyst (sodium hydride) and of the initiator (acetyl-caprolactam) on both polymer viscosity and conversion are given as a function of the polymerization time. From these data, it seems probable that initially there is only a step-addition polymerization; subsequently, transamidation reactions exert their influence especially if a fluid phase is present. This hypothesis is confirmed by consideration of the behaviour of the polymerization in the molten state (220°).

The autocatalytic nature of the anionic polymerization of ϵ-caprolactam with alkali salts

The autocatalytic nature of the anionic polymerization of ϵ-caprolactam with alkali salts

The induction pf period in the polymerization of ϵ-caprolactam and ζ-eonantholactam under various conditions

The induction pf period in the polymerization of ϵ-caprolactam and ζ-eonantholactam under various conditions

On the mechanism of the polymerization of ε‐caprolactam. IV. Polymerization in the presence of water and either an amine or a carboxylic acid

AbstractIn continuation of previous kinetic work on the hydrolytic polymerization of εcaprolactam (CL) (Part I–III) in which evidence was obtained that all the predominant reactions are catalyzed by endgroups, special experiments were undertaken in order to study the specific role played by the NH2 and COOH endgroups. To that end kinetic runs at 221°C. were performed with Cl‐water systems (containing 5–7 mole‐% of water) in which the symmetry of the concentrations of NH2 and COOH groups was disturbed by the addition of about 1 mole‐% of either an amine or a carboxylic acid [hexamethylenediamine (HMD), adipic acid (ADA), and sebacic acid (SBA) were used]. The concentrations of unconverted lactam and of amino and carboxyl groups were determined as previously described; special techniques were worked out for the determination of the small concentrations of unconverted HMD, ADA, and SBA. The main observations are: (1) added HMD disappears much more rapidly from the reaction mixture than added ADA or SBA; (2) the dicarboxylic acids have considerable accelerating effect on the formation of endgroups. Only a general qualitative discussion of these results is given. The principal deductions may be summarized as follows. (a) The initial reaction of the polymerization process, the hydrolysis of CL, is found to be catalyzed by COOH groups. (b) The main contribution to the increase in chain length is furnished by the addition of CL to NH2 endgroups exclusively (aminolysis of the lactam molecule). (c) This addition reaction is catalyzed by COOH groups. (d) Probably, the polycondensation reaction of NH2 and COOH groups is also catalyzed by COOH groups.

Studies on Polymerization and Depolymerization of ε-Caprolactam Polymer. V. On the Reaction Mechanism of the Catalytic Polymerization of ε-Caprolactam by Alkali Metal

Abstract When alkali metal reacts with ε-caprolactam, it was found experimentally that hydrogen and N-alkali metal ε-caprolactam are produced at first. The rate of polymerization of ε-caprolactam in the presence of N-alkali metal derivative was studied. The change in the electric conductivity during polymerization was also measured. In this case the polymerization is expected to proceed by an ionized molecule.

Studies on Polymerization and Depolymerization of ε-Caprolactam Polymer VI. On the Reaction Mechanism of the ε-Caprolactam Polymerization by Alkali Metal Compound

Abstract The basic compound of alkali metal reacts with ε-caprolactam and gives at first N-alkali metal ε-caprolactam. It can cause the polymerization of ε-caprolactam. The boiling of the reaction phase is necessary for making the reaction proceed. The polymerization is especially rapid and reproducible in case of dispersing alkali metal compound colloidally in ε-caprolactam. It is supposed, therefore, that the solid surface of the catalyser is a very important factor in the polymerization.

Heterochain polyamides Communication 3. Kinetics of polymerization of?-caprolactam in presence of hexamethylenediammonium adipate

1. The kinetics of polymerization ofe-caprolactam were investigated, and it was shown that the mechanism of growth of the macromolecules changes at different stages of the process. 2. It was shown that the polymerization of a -caprolactam follows a bimolecular course.

Studies on Synthetic Polyamides (VI) Dimeric ε-Caprolactam

Abstract The fluffy sublimate (m. p. 341–342°), byproduct of the polymerization of ε-caprolactam, is shown to be neutral cyclic dimeric capramide (IV) (a 14-membered ring compound).