Coagulation Bath in The Production of Membranes of Nanocomposites Polyamide 6/Clay

Abstract

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.

Preparation of Polyamide-6/zeolite-Y Hybrid Membranes, and the evaluation of their Structural, Physical and Mechanical Properties

“…It is noticed that the characteristic peaks of the zeolite Y disappears when it is incorporated to the polymeric matrix, indicating that a nanocomposite with exfoliated structure or partially exfoliated was obtained as shown in Figure 9. This result is consistent with others [6,7,9], where bentonite and montmorillonite were added to PA6 membranes . Peaks in the range of 17-26° in Figure 8 correspond to reflections related to the crystalline planes (200) and (002) of the α phase of polyamide-6, they were also observed in literatures [6,9,26].…”

“…The solution was spread on a glass plate with a glass stick. The solvent was left to evaporate partially from the casting solution until the membrane becomes white in color, then the glass plate was immersed in a precipitation bath containing formic acid (10%) [6]. After precipitation, the membrane was removed and washed with distilled water.…”

“…The most widely used synthetic polymers in membranes are polyamide-6 (PA-6), polyamide-66 (PA-66), polysulfone (PS), polyethersulfone (PES), polyvinylidene difloride (PVDF) and polypropylene(PP) because they have good chemical, thermal and mechanical stabilities [4]. Among them, polyamide-6 has an excellent combination of desirable properties, including hydrogen bond in molecular chains [5], fatigue resistance, high tensile strength, abrasion and good toughness [6]. These properties make it one of the major engineering and high performance plastic [5], and a good choice in the prepareation of the hybrid membranes [7,8,9].…”

“…These properties make it one of the major engineering and high performance plastic [5], and a good choice in the prepareation of the hybrid membranes [7,8,9]. Addition of inorganic nanoparticles (clay) considerably improves the filtration of membrane by controlling the formation and growth of macrovoids [6]. It also increases the number of small pores and as a result improves hydrophilicity, porosity, permeability, mechanical and antifouling properties [6].…”

“…Addition of inorganic nanoparticles (clay) considerably improves the filtration of membrane by controlling the formation and growth of macrovoids [6]. It also increases the number of small pores and as a result improves hydrophilicity, porosity, permeability, mechanical and antifouling properties [6]. Different types of nanomaterials have been investigated for such applications including zeolite, silica, carbon nanotubes, mesoporous carbon, pure metals and Egyptian Journal of Chemistry http://ejchem.journals.ekb.eg/ ________________________________________________ Egypt.…”