Polyamide from lactams by reactive rotational molding via anionic ring-opening polymerization: Optimization of processing parameters

Abstract

A reactive rotational molding (RRM) process was developed to obtain a PA6 by activated anionic ring-opening polymerization of epsilon-caprolactam (APA6). Sodium caprolactamate (C10) and caprolactam magnesium bromide (C1) were employed as catalysts, and difunctional hexamethylene-1,6-dicarbamoylcaprolactam (C20) was used as an activator. The kinetics of the anionic polymerization of !-caprolactam into polyamide 6 was monitored through dynamic rheology and differential scanning calorimetry measurements. The effect of the processing parameters, such as the polymerization temperature, different catalyst/activator combinations and concentrations, on the kinetics of polymerization is discussed. A temperature of 150°C was demonstrated to be the most appropriate. It was also found that crystallization may occur during PA6 polymerization and that the combination C1/C20 was well suited as it permitted a suitable induction time. Isoviscosity curves were drawn in order to determine the available processing window for RRM. The properties of the obtained APA6 were compared with those of a conventionally rotomolded PA6. Results pointed at lower cycle times and increased tensile properties at weak deformation

Synthesis and characterization of star-branched polyamide 6 via anionic ring-opening polymerization with N , N′ , N″ -trimesoyltricaprolactam as a multifunctional activator

“…The structure of TMTC was characterized with NMR and HRMS. e-Caprolactam magnesium bromide (CL-Mg-Br) was chosen to catalyze the CL anionic ROP due to its high catalytic activity [21]. The polymerization results were summarized in Table 1.…”

Single-polymer composites (SPCs): Status and future trends

“…The latter, being exotherm, is superimposed to polymerization which should be taken into account [40,41]. Nowadays there is a vivid interest to produce PA6-based SPCs by this technique [45,46], fuelled by the revival of the "old" activated anionic polymerization of ε-caprolactam owing to more robust catalyst/activator systems [46,47].…”

Optimierung der Verbundhaftung von mehrlagigen, rotationsgeformten Bauteilen durch Einbringen einer mehrphasigen Zwischenschicht

“…Neben Polyethylenen werden unter anderem Polyvinylchlorid, Polypropylen oder Polyamide verwendet [1,4,5]. Zudem wurden bereits Untersuchungen durchgeführt, die darauf abzielen, neben thermoplastischen Werkstoffen auch reaktive Systeme mittels Rotationsformen zu verarbeiten [6][7][8].…”