Josiane da R. Silvano

Bio: Josiane da R. Silvano is an academic researcher from Ponta Grossa State University. The author has contributed to research in topics: Montmorillonite. The author has an hindex of 1, co-authored 1 publications receiving 40 citations.

Processing Degradation of Polyamide 6/Montmorillonite Clay Nanocomposites and Clay Organic Modifier | NIST

Abstract: Abstract Under injection molding conditions, typical of industrial processing, in situ polymerized montmorillonite/polyamide 6 nanocomposites significantly degraded, producing a four-fold increase in e-caprolactam (monomer) content and a significant reduction in number average molecular mass, as compared to the as-received nanocomposite. Degradation was believed to occur via peptide bond scission following attack by water that is most likely released from the polymer and the montmorillonite clay surface at the 300 °C (12.5 min) processing conditions. Under identical injection molding conditions, virgin polyamide 6 number average molecular mass did not decrease (within experimental uncertainty); however, a small increase in monomer content was observed. Characterization methods included solution 13 C nuclear magnetic resonance spectroscopy, infrared spectroscopy, gel-permeation chromatography, and thermal gravimetric analysis.

The Effect of Multiple Extrusions on the Properties of Montmorillonite Filled Polypropylene

Abstract: Nanocomposites have attracted a great deal of interest during recent years. Much research has been conducted towards the incorporation of clay particles in a polypropylene matrix. However, the effect of extrusion reprocessing on the material properties has not been studied in depth. In this study, composites of polypropylene (PP) reinforced with organic modified montmorillonite (MMT) (4 wt%) and coupling agent were subjected to 15 extrusion cycles. The materials were characterized by melt flow index (MFI), plate-plate rheometry, tensile testing and impact measurements, differential scanning calorimetry (DSC), X-ray diffraction (XRD) and scanning electron microscopy (SEM). The results showed an improved intercalation of the MMT clay in the first few extrusions, thus improving the mechanical properties. Increasing the processing steps furthermore lead to a decrease in elastic modulus and impact strength, which was attributed to a reduction in matrix-filler interaction, most probably caused by organoclay degradation as shown by thermogravimetric analysis (TGA). The results of this study provide a useful insight in either the recycling of PP/MMT waste streams or the use of clay particles as a strengthening filler agent in the recycling process of different polymer waste streams.

Effect of Extrusion on the Mechanical and Rheological Properties of a Reinforced Poly(Lactic Acid): Reprocessing and Recycling of Biobased Materials.

Abstract: The aim of this research paper is to study the behaviour of a common used biopolymer (Poly(Lactic Acid) (PLA)) after several reprocesses and how two different types of additives (a melt strength enhancer and a nanoadditive) affect its mechanical and rheological properties. Systematic extraction of extrudate samples from a twin-screw compounder was done in order to study the effect in the properties of the reprocessed material. Detailed rheological tests on a capillary rheometer as well as mechanical studies on a universal tensile machine after preparation of injected specimens were carried out. Results evidenced that PLA and reinforced PLA materials can be reprocessed and recycled without a remarkable loss in their mechanical properties. Several processing restrictions and specific phenomena were identified and are explained in the present manuscript.