PEI Polyetherimide

PEI is a tough amorphous thermoplastic resin, with good mouldability and chemical resistance, marketed by GE Advanced Materials as ULTEM. PEI is one of the intrinsically flame resistant polymers used to manufacture injection moulded PCB and self-extinguishing component casings. 

One of the latest additions to GE s PEI portfolio is ULTEM XHT which the manufacturer has developed to be the highest heat, injection mouldable, amorphous resin on earth . Its features are that it combines extremely high heat resistance, high chemical resistance, flame retardance, transparency and stability. It can be moulded using existing equipment and is seen as a potential replacement for glass, metal and other high heat-resistance materials. 

Blends of PAEK and PEI can offer increased Tg, good chemical resistance at the lower PEI levels and reduced cost relative to pure PAEK. In particular PEI can be used to build the heat distortion temperature (HDT) of PAEK. Such blends find uses where PAEK-like performance is required in combination with an improved HDT. There are also applications in which the PEI is used above its Tg as a melt adhesive. For example, laminates of copper foil and PEEK/ PEI blend films can be produced in which the copper adheres to the hot, amorphous blend which subsequently crystallises to produce a chemical and solder-resistant structure. Mitsubishi has produced flexible printed circuit boards based on this concept [9]. 

There are also situations in which PEI has been used to compatabilise PAEK with other PEI-miscible polymers. For example, PEN/PEI/PEEK ternary blends have been biaxially stretched [10,11]. PEI is miscible with PEN and the PEEK is added to enhance the crystallisability of the blend and create a strain-hardening material. PEI has also been used to enhance the compatability of PEEK and polyethersulfone (PES) [12]. The PES can be encapsulated in a PEEK/PEI phase which further reduces the required amormt of PAEK. 

Introduced by GE Plastics in 1982, polyetherimide (PEI) is an amorphous thermoplastic offering outstanding high heat resistance and strength. The high heat resistance and heat stability are attributable to its imide structure. PEI also has resistance to a broad range of chemicals, and is inherently flame resistant with low smoke emission. A major component of PEI is bisphenol A, which is also produced by GE Plastics, mainly for use in polycarbonates. 

Polyetherimide is a hybrid between polyarylethers and polyimides. The imides impart high temperature performance and the inclusion of ether groups allows melt processing. The properties of PEI are in fact closer to PES than to non-melting polyimides. PES and PEI therefore compete 

The main advantages of PEI are its high tensile strength at 20 °C more than either PES or polysulfone. It also has lower water absorption than PES. Continuous use temperature is around 170 °C compared to PES of 180 °C. The main disadvantage is that stress cracking occurs when in 

Elastic modulus (MPa) (tensile with 0.2% water content) 2967 8970-11040 

A wide range of high performance applications have been developed for polyetherimide resins. The main markets for PEI resin and compounds are electrical/electronic applications, aircraft/aerospace interiors, food service (ovenable), high temperature lighting bezels and reflectors, medical instrument trays, institutional kitchenware and under-hood automotive applications. Automotive applications account for around a half of PEI market volume. 

Peak Notation Assignment of Main Peaks Molecular Weight Retention Index Relative Intensity 

2) Carroccio, S. Puglisi, C. Montaudo, G. Macromol. Chem. Phys. 1999, 200, 2345. 

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A number of amorphous thermoplastics are presently employed as matrices in long fiber composites, including polyethersulfone (PES), polysulfone (PSU), and polyetherimide (PEI). AH offer superior resistance to impact loading and higher interlaminar fracture toughnesses than do most epoxies. However, the amorphous nature of such polymers results in a lower solvent resistance, clearly a limitation if composites based on such polymers are to be used in aggressive environments. 

Some of the common types of plastics that ate used ate thermoplastics, such as poly(phenylene sulfide) (PPS) (see Polymers containing sulfur), nylons, Hquid crystal polymer (LCP), the polyesters (qv) such as polyesters that ate 30% glass-fiber reinforced, and poly(ethylene terephthalate) (PET), and polyetherimide (PEI) and thermosets such as diaHyl phthalate and phenoHc resins (qv). Because of the wide variety of manufacturing processes and usage requirements, these materials ate available in several variations which have a range of physical properties. 

The PEEK resia is marketed as aeat or filled pellets for iajectioa mol ding, as powder for coatiags, or as preimpregaated fiber sheet and tapes. Apphcations iaclude parts that are exposed to high temperature, radiation, or aggressive chemical environments. Aerospace and military uses are prominent. At present, polyamideimide (PAl) resia and poly(arylene sulfides) are the main competitors for apphcations requiring service temperatures of 280°C. At lower temperatures, polyethersulfones, amorphous nylons, and polyetherimides (PEI) can be considered. 

PEI homopolyesters. See Poly(ethylene isophthalate) (PEI) homopolyesters PEIs. See Polyetherimides (PEIs)... 

Polyetherimide-polysiloxane multiblock copolymers, 24 716 Polyetherimides (PEI), 10 217—218 Polyether impression materials, 8 332-333 Poly(ether ketones) (PEK), 10 197-199 Polyether polyols, 25 455-456,464,468t, 470 propylene oxide polymerization to, 20 793-794, 812 Poly ethers, 12 663... 

Mat and continuous glass fibre reinforcements theoretically all the thermoplastics are usable in these forms, but up to now developments have concentrated on polypropylenes (PP), polyamides (PA) and thermoplastic polyesters (PET) fibre-reinforced PEEK, polyetherimide (PEI) and polyphenylene sulfide (PPS) are used for high-performance applications. They are presented in a range of forms from stampable sheets to pellets, prepregs, ribbons, impregnated or coated continuous fibre rods. More rarely (as in the case of PA 12, for example), the thermoplastic is provided in liquid form. 

The initial announcement for the commercial preparation of polyetherimides (PEIs) was made by General Electric in 1982 under the trade name Ultem. The final reaction involves the imidization of a diacid anhydride through reaction with a diamine, here w-phenylenedia-mine (structure 4.62). The ether portion of the polymer backbone results from the presence of ether linkages within the diacid anhydride. 

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. 

The phase separation behavior during curing of polyetherimide (PEI) modified diglycidyl ether of bisphenol A (DGEBA) epoxy and PEI modified bisphenol A dicyanate (BPACY) were studied using SEM, light scattering, and dynamic mechanical analyzer. 

Diglycidyl ether of bisphenol-A (DGEBA), epoxy resin (YD 128, Kuk Do Chem., Mn = 378), and bisphenol-A dicyanate (BPACY, Arocy B-10, Ciba-Geigy) were used as the thermoset resin. 4,4 -diaminodiphenyl sulfone (DDS, Aldrich Chem. Co.) was used as a curing agent for epoxy. Polyetherimide (PEI, Ultem 1000, General Electric Co., M = 18,000) and 2-methyl imidazole (2MZ, Aldrich Chem. Co.) were used as the thermoplastic modifier and catalyst. 

Matrix materials for commercial composites are mainly liquid thermosetting resins such as polyesters, vinyl esters, epoxy resins and bismaleimide resins. Thermoplastic composites are made from polyamides, polyether ether ketone (PEEK), polyphenylene sulfide (PPS), polysulfone, polyetherimide (PEI) and polyamide-imide (PAI). 

Tmr corresponds to the temperature of maximum rate of weight loss under air atmosphere at a heating rate of 5°C/min, and D to the average bundle diameter obtained by SEM micrographs. Polyetherimide (PEI) is the compatibilizing agent. 

Table IV. Fiber Critical Lengths (Lc, ran) and Standard Deviations (SD) of Fibers Embedded in Polysulfone (PS), Polycarbonate (PC) and Polyetherimide (PEI)...

Typical UF membrane materials are polysulfone (PS), poly ether sulfone (PES), polyetheretherketone (PEEK), cellulose acetate (CA), polyacrylonitrile (PAN), polyvinylidene fluoride (PVDF), polyimide (PI), and polyetherimide (PEI) ... 

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