Polyetherimides fluorinated

Y. Zhang, R. Wang, Fabrication of novel polyetherimide-fluorinated silica organic-inorganic composite hollow fiber membranes intended for membrane contactor application, J. Memb. Sci. 443 (2013) 170-180. 

This review summarizes our work at the University of Bayreuth over the last few years on improving the electret performance of the commodity polymer isotactic polypropylene (Sect. 3) and the commodity polymer blend system polystyrene/polyphenylene ether (Sect. 4) to provide electret materials based on inexpensive and easily processable polymers. To open up polymer materials for electret applications at elevated temperatures we concentrated our research on commercially available high performance thermoplastic polyetherimide resins and synthesized several fluorinaled polyetherimides to identify structure-property relations and to improve further the performance at elevated temperatures (Sect. 5). 

Table 3 summarizes the fluorine content, inherent viscosities, and thermal properties of the synthesized fluorinated polyetherimides The inherent viscosities (for conditions, see footnote of Table 3) of the F-PEI polymers varied from 0.34 to 0.72 dL/g. PEI 7a was obtained at an inherent viscosity of 0.47 dL/g, which is comparable to the value of commercial Ultem 1000 (17 =0.5dL/g). DSC measurements showed that all F-PEIs are amorphous with a Tg range from 220 °C to 247 °C. Within the first series denoted as 7a, 7b, and 7d, Tg between 220 and 224 °C were detected, whereas 7c exhibits a slightly higher Tg of 232 °C. Polymers 8a, 8b, and 8d show Tg between 234 and 236 °C, whereas the Tg of 8c is at 247 °C. 

Scheme 4 Chemical structures of the synthesized fluorinated polyetherimides...

Both polyamide-imide and polyetherimide have high heat distortion temperature, tensile strength, and modulus. Polyamide-imide is useful from cryogenic temperatures up to 260°C. It is virtually unaffected by aliphatic and aromatic chlorinated and fluorinated hydrocarbons and by most acid and alkali solutions. These polymers are used in high-performance electrical and electronic parts, microwave appliances, and under-the-hood automotive parts. Typical automotive applications include timing gears, rocker arms, electrical connectors, switches, and insulators. 

With regard to ultraviolet (UV) radiation, several polymers, reinforced or unreinforced, have excellent resistance to it. This inclndes polyether ether ketone, diallyl isophthalate, polyetherimide, vinylacetate, silicones, and several fluorinated polymers, such as polyvinyl fluoride, polyvinylidene fluoride, perfluoroalkoxy ethylene, ethylene-chlorotrifluoroethylene, and flnorinated ethylene-propylene copolymer (Table 11.2). 

Structural studies of polymer surfaces materials that have been studied include polymethyl methacrylate (PMMA) [22], PMMA-polypyrrole composites [23], poly(chloromethyl styrene) bound 1,4,8,11 tetrazacrylotetra decane poly(chloromethyl styrene) bound theonyl trifluoroacetone [24], polydimethyl siloxane-polyamide copolymers [25], PS [26], ion-implanted PE [27], monoazido-terminated polyethylene oxide [28], polyurethanes [29], polyaniline [30], fluorinated polymer films [31], poly(o-toluidine) [32], polyetherimide and polybenzimidazole [33], polyfullerene palladium [34], imidazole-containing imidazolylethyl maleamic acid - octadecyl vinyl ether copolymer [35], polyphenylene vinylene ether [36], thiphene oligomers [37], fluorinated styrene-isoprene derivative of a methyl methacrylate-hydroxyethyl methacrylate copolymer [38], polythiophene [39], dibromoalkane-hexafluorisopropylidene diphenol and bisphenol A [40], and geopolymers [41],... 

Polyetherimide (PEI) 7 Polyvinylidene Fluorides (PVDF) 9 Fluorinated Ethylene Propylene Copolymer (FEP) 8-9... 

The combination of processability and performance provided by these polymers makes them natural candidates for applications such as microelectronics laminates as well as structural and dielectric composites (2). The versatility provided by the use of phenolic feedstocks has allowed the extension of this chemistry into polyesters (i), classical photoresist chemistry (4), and thermally crosslinkable thermoplastics (5). It has also provided a method for thermally processing low molecular weight imide-containing oligomers into high molecular weight polyetherimides (d) In addition, oligomers which are useful as fluorinated lubricant fluids have been prepared (7). 

In a recent example, the interfacial grafting reaction between MWNTs and a newly designed non-fluorinated polyetherimide (BisADA-DCB) (Scheme 12.1) was carried out using simple carboxylic acid-functionaUzed MWNTs [42]. The tensile strength and modulus of the BisADA-DCB films grafted with carboxylic acid-... 

Other strategies for producing hydrophobic membranes for MD are the modification of hydrophilic polymers or ceramic materials. Qtaishat et al. [144] produced two different types of hydrophobic surface-modifying macromolecules (SMMs) and prepared hydrophobic/hydrophilic polyetherimide composite membranes. The SMMs blended PEI membranes achieved better DCMD fluxes than those of a commercial PTFE membrane tested under the same conditions. Similarly fluorinated SMMs were used to modify hydrophilic poly(sulfone) [145]. Krajewski et al. [146] used lH,lH,2H,2H-perfluorodecyltriethoxysilane to create a hydrophobic active layer on commercial tubular zirconia membranes supported on alumina. The produced membranes were tested in air-gap MD (AGMD). Hendren et al. [147] used 1H,1H,2H,2H-perfluorodecyltriethoxysilane, trichloromethylsilane, and trimethylchlorosilane to modify, by surface grafting, two types of alumina Anodise ceramic membranes. The authors demonstrated that this surface treatment was effective and tested the produced membranes in DCMD. 

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