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

Blends of recycled poly(butylene terephthalate) (PBT) parts obtained from scrapped cars, and virgin polypropylene (PP), were prepared in a twin‐screw extruder at different compositions. Selected compositions were also prepared with the presence of ethylene‐co‐glycidyl methacrylate copolymer (E‐GMA) and ethylene/methyl acrylate/glycidyl methacrylate terpolymer (E‐MA‐GMA) compatibilizers. The effect of the composition and the type of compatibilizer, as well as the mixing conditions, on the morphology phase, thermal, viscoelastic behavior, and mechanical properties of the blends has been investigated. Blends PP/PBT of various composition exhibit a coarse morphology and a poor adherence between both phases, resulting in the decrease of ductility, whereas at weak deformation, PBT reinforced the tensile properties of PP. Addition of E‐GMA and E‐MA‐GMA to the PP/PBT blend exhibited a significant change in morphology and improved ductility because of interfacial reactions between PBT end chains and epoxy groups of GMA that generate EG‐g‐PBT copolymer. Moreover, thermal and viscoelastic study indicated that the miscibility of PP and PBT has been improved further and the reactions were identified. The E‐MA‐GMA results in the best improvement of ductility. POLYM. ENG. SCI., 2008. © 2008 Society of Plastics Engineers

Blending polypropylene to recycled PA6 industrial wastes at different compositions, with and without compatibilizer PPgMA was produced in a corotating twin screw extruder where, polypropylene acts as the polymer matrix and polyamide as the dispersed phase. Several techniques were used to investigate the morphology, thermal, viscoelastic and tensile properties of these blend. Binary PP/PA6 blends showed the presence of PA6 particles dispersed in the PP continuous phase and exhibited a coarse morphology. Increasing PA6 contents in the blend increased their crystallinity and their size and improved the tensile properties at weak deformation. In addition to compatibilizer PPgMA, the morphology shows lower diameters and a decrease in size of the dispersed PA6 particles. The interfacial adhesion was also improved, as a result of the creation of an interphase that was formed by the interaction between the formed PPgPA6 copolymer in situ and both phases. This interphase induced an improvement in tensile properties. The PPgPA6 copolymer generated by the interphase was identified with DMA analysis thanks to an additional transition in loss modulus curves.

Rotational molding is a shear-free and pressure-free process used to manufacture hollow plastic parts with relatively low investment [1]. With the rotational molding industry presently being dominated by powdered plastics, in particular polyethylene with limited properties, moulders are being forced to use other forms of plastic processing. Other resins currently used by the industry such as polycarbonate and nylon offer better properties, but at a cost.Reactive rotational molding (RRM) is an important way to overcome these problems, this process offers manufactures numerous benefits over the conventional powder process including shorter cycle times, lower processing temperatures and improved in material properties [2]. Additionally the use of RRM process allows the synthesis of engineering thermoplastic as polyamide 6 with a high molecular weight through anionic polymerization of caprolactam by the aid of chain initiators and catalyst. The advantage of the anionic polymerization of caprolactam have been put to use in reactive polymerization-molding process, namely Rotational molding has been regarded as a plastic molding method with great potential. The process offers virtually stress free products having no weld lines or material wastage, and utilizes relatively inexpensive molds. Yet its widespread growth is hindered due to long production cycle times, which are limited by the time required to heat up and cool down the mold and the product. This presentation is about the study of making multilayer PP/PA6 parts with the reactive rotational molding process. Different studies have already been made in the past about rotational molding or about reactive process of monolayer part. The aim of this work is to reduce cycle time by making a layer via anionic polymerization of caprolactam, and them to compare each process. This presentation is divided into two parts: the first part deals with rheological, dieclectric aland thermal analysis to investigate the effect of mixtures and the crystallization/polymerization effect; the second part deals with the processing of bilayer parts. Firstly, different mixtures of catalysts and activators were investigated by Rheology and thermal analysis in order to determine which mixture would be the most appropriate for the rotational molding process: 2 2 (2% of activator and 2% of catalyst), 3 3, 4 4 and 6 6. In the second step, different processing investigations have been done in order to study the influences of the parameters like oven time or cooling time. An experimental analysis of heat transfer in reactive rotational molding process was also lead. By using an instrumented mold associated with a radio transmission data acquisition system, we demonstrate that the rotational parts of the bilyar PP/PA6 (reactive way) can be obtained with optimised conditions in correlation with the results of rheology and dielectric measurements. Moreover, the results allows us that it is possible to make bilayer reactive part with the rotational molding process by using less energy in a shorter t...