The nanocomposites have an extensive use in the current process of membrane preparation, taking into account their unique features as membranes. Thus, the study of nanocomposite processing to obtain membranes is highly important. In this work, Brazilian clay was used (Brasgel PA) for the preparation of polyamide/clay nanocomposite. The nanocomposites were produced in a high rotation homogenizer and in a twin screw extruder. From the nanocomposites and pure polymers processed in the two equipments, membranes were prepared by the immersion-precipitation method, using formic acid as solvent. By X-ray diffraction (XRD), the formation of exfoliated and/or partially exfoliated structures with changes in the crystalline phases of the polyamide was observed. From scanning electron microscopy images, it was observed that the processing clearly influenced the membrane morphology.
Membranes of polyamide 6 and its nanocomposites with 3 and 5% of clay were obtained by the phase inversion method using distilled water and solvent as the coagulation bath, 10 and 30% of acid was used, in order to change the membranes morphology/porosity. By XRD analysis, the obtained nanocomposites showed an exfoliated and/or partially exfoliated structure, it was also seen two characteristics peaks of the polyamide 6 phases (α and γ). For the membranes, the characteristic peak γ of the membrane disappeared, being evident the peaks α 1 and α 2. By SEM the PA6 membrane almost doesn't have pores in its surface, with an addition of clay had an increase in the quantity of surface pores. In the cross section of the PA6 membrane, an extremely thin selective layer, adding the clay the selective layer became thicker and a better defined porous support was obtained. From the acid in the coagulation bath the PA6 membrane continued with a few pores structure. For the nanocomposites there was an increase in size and a better uniformity of the pores. In the cross section the presence of the bath decrease the membrane filtering, also modifying a uniformity of the pores.
In this work, compounds based on two grades of polypropylene (PP), i.e., PP H503 or PP H103 with residues of Big bag fabrics (R BB ) were processed in a corrotational twin screw extruder with R BB content ranging from 10% to 50% of the weight. Then, their thermal properties were investigated through Differential Scanning Calorimetry (DSC) and Thermogravimetry (TG); mechanical by tensile and impact; thermomechanic by heat deflection temperature (HDT); and their morphology by Scanning Electron Microscopy (SEM). With the aim to add maximum R BB content without considerable damage to the properties of neat PPs, it was observed that addition of 10%, 30% and 50% of R BB did not significantly interfere in the PP matrices, being the compound PP + 30% R BB which one presented more successful properties, leading to reused compounds with higher performance and lower costs at same time.
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