Hexadecyltrimethylammonium bromide-modified sericite mica-based polyimide composites: A comparison between In situ polymerization and solution intercalation processes

In order to increase the spacing between clay layers and study the effects of processing on the morphology and properties of PI/organoclay composites, polyimide (PI) composites containing multi-step procedure-modified sericite mica were prepared via in situ polymerization and solution intercalation. The structure-property relationships of the composites were studied by means of X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), dynamic mechanical analysis (DMA), thermogravimetric analysis (TGA), X-ray photoelectron spectroscopy (XPS). The results of XRD patterns revealed d 002 -spacing of clay was expanded from 0.99 to 2.77 nm. TEM photographs indicated majority of the organoclay exhibited an exfoliated morphology in composites prepared by in situ polymerization. TGA summarized the composites prepared by solution intercalation and in situ polymerization had a 9 and 29 oC increment in T 5 compared with pristine PI respectively. XPS indicated the interaction of organoclay and polymer matrix in composites prepared by in situ polymerization was stronger than other types of composites. The glass transition temperature ( T g ) and storage modulus of the composites prepared via in situ polymerization was much higher. Especially the T g of this composites revealed a 33 °C increase compared with pure PI.