Characteristics and properties of polyimide/vanadium oxide hybrid membranes

A series of polyimide/vanadium pentoxide (PI/V2O5) hybrid film has been successfully fabricated through the in situ formation of V2O5 within a polymer matrix by sol–gel process. The polyamic acid (PAA) is prepared from 4,40 -diaminodiphenyl ether (ODA) and 3,30 ,4,40 -benzophenonetetracarboxylic anhydride (BTDA) in N-methylpyrrolidinone (NMP) solvent. Then different amounts of Bis-(2,4-pentanedionato) vanadium oxide are incorporated into polyamic acid (PAA) matrix, respectively and then thermally imidized to form PI/V2O5 hybrid membranes. The imidization temperature and time are optimized by FTIR measurements through the observation of V2O5 absorption peak. The influence of V2O5 content on the thermal stability, morphology and mechanical properties of PI/V2O5 hybrid films are studied.

Polyimide containing V2O5 has been successfully prepared by sol–gel method. There is an obvious absorption peaks of V2O5 in the range of 700–430 cmÀ1. The intensity of absorption peak is increased with V2O5 content. Based on SEM result, the fractured cross-section surface roughness of the hybrid film also increases with V2O5 content. The incorporation of V2O5 causes a decrease in thermal stability of hybrid films. However, the hybrid films still possess good thermal property. According to the results of DMA study, the storage modulus of the hybrid films is reinforced with addition of V2O5. It also points that the addition of V2O5 shows higher Tg as compared with pure PI. Besides, the existence of V2O5 and amorphous morphology of hybrids can be indicated by X-ray detection.