Polymerization of lactams, 45.The ¹³C‐NMR analysis of copolymers of 6‐caprolactam with 12‐dodecanelactam

Abstract

The copolymers of 6-caprolactam with 12-dodecanelactam were prepared by the hydrolytic, cationic and spontaneous mechanisms. The composition of copolymers was determined by means of %-NMR spectra and information about the relative reactivity of individual monomers, the type of copolymer and the mean length of homogeneous blocks was obtained from intensities of carbonyl signals. It has been proved that a random copolymer is formed at the equimolar initial ratio of monomers irrespective of the polymerization mechanisms used. Investigation of the time course of hydrolytic copolymerization proved the higher reactivity of 6-caprolactam in comparison with 12-dodecanelactam. ZUSAMMENFASSUNG:Es wurden Copolymere von 6-Caprolactam und 12-Dodecanlactam nach hydrolytischem, kationischem und spontanem Mechanismus dargestellt . Die Zusammensetzung der Copolymeren wurde durch I3C-NMR Spektren analysiert. Aufgrund der Carbonylsignalintensitat wurden Informationen iiber die relative Reaktivitat der einzelnen Monomeren, den Typ des Copolymeren und die mittlere Lange der homogenen Blocke gewonnen. Es wurde bewiesen, da8 bei einem aquimolaren Ausgangsverhaltnis der Monomeren, ohne Rucksicht auf den Reaktionsmechanismus, ein statistisches Copolymeres entsteht . Das Studium des Zeitverlaufes der hydrolytischen Polymerisation bewies die hohere Reaktivitat des 6-Caprolactams im Vergleich mit dem 12-Dodecanlactam.

Anionic copolymerization of nylon 6/12: A comprehensive review

“…The studies on these random or block structures by direct structural analysis techniques, such as X-ray [54] diffractometry, 13 CNMR, and IR analysis or by determination of the number of melting points through differential scanning calorimetry (DSC) analysis have been reported [9,27,28,30,31,42,43,48,[55][56][57][58]. IR absorption spectra are also capable of showing polyamides characteristic band absorption [7,42,48,59].…”

“…These parameters specify the sequence of comonomers in the polymer backbone and, therefore, have a great impact on the resulting structure, configuration, and final properties. Since the CL's activity is higher than that of LL due to its structure , the CL tends to enter the copolymer chain more rapidly than LL, so a lower amount of LL end up in the copolymer chain, which results in a block copolymer structure. On the other hand, if there is a significant difference between the acidity of comonomers, a certain degree of block units would appear in the copolymer structure.…”

“…Lactam polymerization can be initiated not only by bases but also by acids and water. Initiation by water, known as hydrolytic polymerization, is carried out in the industrial polymerization of ε-caprolactam (CL) to form nylon 6; however, it is seldom used for other lactams [2,[6][7][8][9]. Cationic initiation involving positively charged intermediate with acids has not interested many researchers due to the low conversion and the low-molecular weight of polyamides produced by this procedure [9][10][11][12][13][14].…”

Continuous Polymerization and Copolymerization of Lauryl Lactam in a Modular Corotating Twin Screw Extruder

“…We also describe the copolymerization of lauryl lactam and caprolactam, an area where there has been relatively little effort [19 to 21]. This paper should be read in the context of earlier investigations of caprolactam polymerization in similar twin screw * Mail address: Prof. Dr. J. C. White, Insitute of Polymer Engineering, University of Akron, Ohio, 44325 0301, USA extruders which has been reported by various investigators [22,27] including those in our own laboratory [26,27] 2 Experimental…”

Reactive extrusion for the synthesis of nylon 12 and maleated low‐density polyethylene blends via the anionic ring‐opening polymerization of lauryllactam

“…The rapid anionic polymerization of lactams has received considerable attention since its discovery in the 1950s 1–24. Fast reaction kinetics, a clean polymerization reaction without any byproducts, and a crystalline end product make the anionic ring‐opening polymerization of lactam a competitive choice for the application of reaction‐injection molding, rotational molding, and reactive extrusion and for subsequent continuous shaping to form extrusion profiles and melt‐spun fibers.…”