Polysulfone/polyimide

Membrane asymmetric homogeneous, or microporous (cellulose acetate, polyamide, polysulfone, polyacrylonitrile) composite of a homogeneous polymer film on microporous substructure (cellulose acetate, polyamide, polysulfone, polyimide, polyvinyl alcohol). Usual pore 0.1 to 0.2 jm. 

O2/N2 Air separation Cryogenic distillation SiUcon rubber Polysulfone Polyimide Polyphenylene Ethyl cellulose Ion transport (perovskite) Pd-based Plant installed (Cynara Separex GMS Air Products) Plant installed (Permea) Plant installed (Medal Dow-Generan UBE) Plant installed (Aquilo) Plant installed (Air Liquide) Lab scale Lab scale... 

In EP07708077A3 (Dabou et al. 1996), gas separation polymer membranes were prepared from mixtures of a polysulfone, Udel P-1700 and an aromatic polyimide, Matrimid 5218. The two polymers were proven to be completely miscible as confirmed by optical microscopy, glass transition temperature values and spectroscopy analysis of the prepared mixtures. This complete miscibility allowed for the preparation of both symmetric and asymmetric blend membranes in any proportion from 1 to 99 wt% of polysulfone and polyimide. The blend membranes showed significant permeability improvements, compared to the pure polyimides, with a minor change in the selectivity. Blend membranes were also considerably more resistant to plasticization compared with pure polyimides. This work showed the use of polysulfone-polyimide polymer blends for the preparation of gas separation membranes for applications in the separation of industrial gases. 

Polyether sulfone Polyphenylene oxide Polysulfone Polyimide... 

While the overall growth of composites in the aerospace industry is continuing, epoxy has been facing stiff competition from other materials and the growth rate has been relatively small (2% annually). While epoxies are still used in many exterior aircraft parts, carbon fiber composites based on bismaleimide and cyanate esters have shown better temperature and moisture resistance than epoxies in military aircaft applications. In the commercial aircraft arena, phenolic composites are now preferred for interior applications because of their lower heat release and smoke generation properties during fires. High performance thermoplastics, such as polysulfone, polyimides, and polyetherether ketone (PEEK), have also foimd some uses in aerospace composites. 

Kapantaidakis, G.C., Kaldis, S.P., Sakellaropoulos, G.P., Chira, E., Loppinet, B and Floudas, G. (1999) Interrelation between phase state and gas permeation in polysulfone/polyimide blend membranes. J. Polym. Sci. Part B Polym. Phys., 37, 2788-2798, 8. 

In this section the attention of the reader is called to some particular problems the surface analyst may encounter in analyzing thin surface films treated by various particle beams, essentially in the sputtering regime (from I to 5 keV). In the following subsections some representative studies will be presented in which it is demonstrated how the effects of particle bombardment on surface chemistry can be evaluated, mainly by XPS, for various inorganic compounds (e.g., TiN layers, metal oxides, Cr-O-Si cermet films) and polymeric materials (e.g., polysulfone, polyimide and poly(organosiloxanes)). 

It is important to mention that other thermoplastics such as polypropylene, nylon, modified polyestas, polysulfones, polyimides, polyethermides and modified styrenics are also used as alternate plastic materials for electroplating. However, the strict requirements on aesthetic quality and plate adhesion from the automotive industry, as well as the technical experience of electroplaters with ABS-based plastics, has continued to promote the volume growth of ABS and PC/ABS based products. 

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