The role of octadecylamine as zirconium phosphate intercalating agent on poly biodegradable systems

Biodegradable ternary systems based on poly(vinyl alcohol)/poly(N-vinyl-2-pyrrolidone)/octadecylamine-containing zirconium phosphate were studied. Firstly, the synthesis and intercalation of lamellar zirconium phosphate were accomplished. As precursors, phosphoric acid (H.sub.3PO.sub.4) and zirconium(IV) oxide chloride 8-hydrate (ZrOCl.sub.2·8H.sub.2O) were used in the ratio P:Zr equals 18. ZrP d-spacing was expanded by octadecylamine as an intercalating agent using 1:1 amine:ZrP molar ratio. Ternary systems based on mixing of PVA and PVP water solution at different proportions (30/70, 50/50 and 70/30 mass/mass%) plus the addition of ZrPOct (2 mass%) were carried out. Infrared spectroscopy revealed that the interaction of PVA and ZrPOct was prominent evidencing an action of octadecylamine as compatibilizing agent. X-ray diffraction showed the decrease in PVA crystal size and the ZrPOct new diffraction angles as a function of the arrangement of polymers inside of the ZrPOct. Mass loss derivative thermogravimetric curves indicated polymer segregation and the decrease in PVA rich phase thermal stability. PVA crystallinity degree (X.sub.c), cold crystallization and melting temperatures (T.sub.cc and T.sub.m) were drastically influenced by PVA/PVP compositions and ZrPOct. Dynamic-mechanical measurements supported that octadecylamine altered the polymer-polymer interaction acting as compatibilizing agent. Also, multiphase systems were reached owing to the free and linked octadecylamine molecules which provided variable polymer molecular motion and PVA/PVP participation effectiveness degree of each rich phase. The system was thought for future application as a control drug delivery.