Montmorillonite-based nanocomposites of polybenzoxazole: Synthesis and characterization (I)

Poly(amic acid) was synthesized by means of low-temperature-solution polyme rization of 3,3'-dihydroxybenzidine and pyromellitic dianhydride in N,N-dim ethylacetamide. The precursor polymer was heat-treated at different tempera tures to create a polybenzoxazole (PBO) through a polyimide (PI). PI contai ning the hydroxyl group was rearranged by decarboxylation with heat treatme nt, resulting in a fully aromatic PBO. Hexadecylamine was used as an organo philic alkylamine in organo-clay, We have tried to clarify the intercalatio n of heterocyclic polymer chains to hexadecylamine-montmorillonite (C-16-MM T) and improve tensile properties. It was found that the addition of only a small amount of organo-clay was enough to improve the mechanical propertie s of PBO. Maximum enhancement in the ultimate tensile strength for PBO hybr ids was observed for the blends containing 4% C-16-MMT. The initial modulus monotonically increased with further increases in the C-16-MMT content. (C ) 2001 John Wiley & Sons, Inc.