Polyimides containing ether

Polyimides Containing Ether Linkages, -O-Ar-0-(Ar Bulky Moiety)... 

In addition they may contain ether, amide, carbonyl, sulfone, or other functional groups. References 28 and 29 provide excellent reviews of polyimide chemistry. 

Semicrystalline Polyimides. Semicrystalline polyimides containing carbonyl and ether groups have been synthesized by the group at the NASA Langley Research Center (37). One such material, designated LARC-CPI, which is an acronym for Langley Research Center—Crystalline Polyimide,... 

Polyetherimides (PEI) are polyimides containing sufficient ether as well as other flexibi-lizing structural units to impart melt processability by conventional techniques, such as injection molding and extrusion. The commercially available PEI (trade name Ultem) is the polymer synthesized by nucleophilic aromatic substitution between 1,3-bis(4-nitrophthalimido) benzene and the disodium salt of bisphenol A (Eq. 2-209) [Clagett, 1986]. This is the same reaction as that used to synthesize polyethersulfones and polyetherketones (Eq. 2-206) except that nitrite ion is displaced instead of halide. Polymerization is carried out at 80-130°C in a polar solvent (NMP, DMAC). It is also possible to synthesize the same polymer by using the diamine-dianhydride reaction. Everything being equal (cost and availability of pure reactants), the nucleophilic substitution reaction is probably the preferred route due to the more moderate reaction conditions. 

Polymers obtained using 3,5-diaminodiphenyl ether may be considered as m-phenylenediamine-based polyimides containing phenoxy side groups. A comparison of these two polymer group properties has demonstrated that introduction of phenoxy substituents leads to an increase of polymer solubility and decrease of Tg indicating that phenoxy side groups behave as chemical plasticisers this conclusion is an agreement with the literature [5, 27-31]. 

M.G. Dhara, S. Banerjee, Ruorinated high-performance polymers poly(arylene ether)s and aromatic polyimides containing trifluoro-methyl groups, Prog. Polym. Sci. 35 (8) (2010) 1022-1077. 

Polyimides with flexible linkages have been known from the advent of high temperature aromatic polyimides. In fact, most of the commercial, fully aromatic polyimides contain ketone or ether linkages in their repeating units [69], and early works... 

Any polyimide prepared from diamines or dianhydride containing ether linkages should be classified as a poly(ether imide), but only those copolyimides with at least one ether linkage per imide group in the repeating unit will be considered here. 

Recent work on crystallinity measurements is reported below sulfur containing ether ketones [14], polyethylene glycol [15], polystyrene (PS) [16, 17], (PC) [18], polyphenylene alkene diyls [19, 20], isotactic polypropylene [20, 21], polyethylene [21, 22], polyimide [23], poly(2,5 bis (4-methoxyphenyl) oxycarbonyl styrene [24], polyazomethine esters [25], PET-polybutylene terephthalate blends [26], polycyclohexyl ethylene copolymers [27], polycaprolactone [28], syndiotactic polystyrene [29, 30], polyvinylidene fluoride-trifluorethylene copolymer [30], polyethers [31], isotactic methyl methacrylate [32], soy protein isolate polymers [33], polyamide 6/66 [34], polytrimethylene-2,6-naphthalate [35, 36], PE like polyesters [37], polycyclohexadiene [38], p-dioxolone, L-lactide - polyethylene glycol copolymers [39], ethylene - methacrylic acid copolymers and ionomers [40]. 

A series of new polyimides containing carbonyl and ether connecting groups between the aromatic rings have recently been re-ported. Some of these Pis are semicrystalline, with Tg% from 222 to 247 C and crystkline melt temperatures from 350 to 442 C. The properties of a representative PI shown in structure 6 are reported in Table 10. 

The crude polymer was purified by using NMP-diethyl ether as solvent-nonsolvent. The polyamic acid so prepared was cured at 200°C for 1 h in vacuum to bring about ring closure, and the polyimide-containing metal phthalocyanine rings were obtained [Eq. (14)]. 

Polyimides for use ia molded products and high temperature films can be produced by the reaction of pyromelHtic dianhydride [89-32-7] and 4,4 -diaminodiphenyl ether [13174-32-8] ia DMAC to form a polyamide that can be converted iato a polyimide (13). DMAC can also be used as a spinning solvent for polyimides. AdditionaUy, polymers containing over 50% vinyHdene chloride are soluble up to 20% at elevated temperatures ia DMAC. Such solutions are useful ia preparing fibers (14). 

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