Polyetherimide compounds

Figure 7.9 Uniaxial fatigue test of SABIC Innovative Plastics Ultem polyetherimide compounds with different glass fiber content [1 ]. 

Figure 7.10 Fatigue cycles to failure versus stress in flexure for SABIC Innovative Plastics reinforced LNP polyetherimide compounds.

I itro-DisplacementPolymerization. The facile nucleophilic displacement of a nitro group on a phthalimide by an oxyanion has been used to prepare polyetherimides by heating bisphenoxides with bisnitrophthalimides (91). For example with 4,4 -dinitro monomers, a polymer with the Ultem backbone is prepared as follows (92). Because of the high reactivity of the nitro phthalimides, the polymerkation can be carried out at temperatures below 75°C. Relative reactivities are nitro compounds over halogens, Ai-aryl imides over A/-alkyl imides, and 3-substituents over 4-substituents. Solvents are usually dipolar aprotic Hquids such as dimethyl sulfoxide, and sometimes an aromatic Hquid is used, in addition. 

The UL flammability ratings describe the relative ease of ignition and combustibiUty of plastics. Tests include the measurement of flame propagation, time to self-extinguish, melt and drip with and without flame, and oxygen indexes. Some engineering plastics, eg, polyetherimides, are, as ranked by this test, inherently nonflammable. Others can be made nonflammable by compounding with flame retardants (ERs) such as bromine... 

Polyetherimides are inherently fire resistant, with oxygen indices superior to 47 and a UL94 VO rating. Compounding can improve these performances and certain grades reach an oxygen index of 50. In the event of fire, smoke emissions are low. 

Towflex (Hexcel Composites) is based on carbon, glass or aramid fibres impregnated with polypropylene, polyamide, PPS, polyetherimide, PEEK. Product forms include flexible Towpreg, woven fabric, braided sleeving, UD tape, chopped compression moulding compound, moulded plates, thermoformable laminates. 

Condensation of Dianhydrides with Diamines. The preparation of polyetherimides by the reaction of a diamine with a dianhydride has advantages over nitro-displacement polymerization sodium nitrite is not a by-product and thus does not have to be removed from the polymer, and a dipolar aprotic solvent is not required, which makes solvent-free melt polymerization a possibility. Aromatic dianhydride monomers (8) can be prepared from IV-substituted nitrophthalimides by a three-step sequence that utilizes the nitro-displacement reaction in the first step, followed by hydrolysis and then ring closure. For the 4-nitro compounds, the procedure is as follows. 

S—EB—S (compounds) polyurethane/elastomer block copolymers polyester/elastomer block copolymers polyamide/elastomer block copolymers polyetherimide/polysiloxane block copolymers polypropylene/EPDM or EPR blends polypropylene/EPDM dynamic vulcanizates polypropylene/butyl rubber dynamic vulcanizates polypropylene/natural rubber dynamic vulcanizates polypropylene/nitrile rubber dynamic vulcanizates PVC/ nitrile rubber blends... 

Because the components must initially form miscible solutions or swollen networks a degree of affinity between the reacting components is needed. Therefore, most of the investigations into epoxy IPNs have involved the use of partially miscible components such as thermoplastic urethanes (TPU) with polystyrenes [57], acrylates [58-61] or esters which form loose hydrogen-bound mixtures during fabrication [62-71 ]. Epoxy has also been modified with polyetherketones [72],polyether sulfones [5] and even polyetherimides [66] to help improve fracture behavior. These systems, due to immiscibility, tend to be polymer blends with distinct macromolecular phase morphologies and not molecularly mixed compounds. 

Recovery of aroma compounds PDMS on polyetherimide from wine-must fermentation... 

Thermoplastic polyetherimide Ultem can be formulated with high temperature foaming agents such as 5-phenyldihydro-l,3,4-oxadiazinone to produce structural form products [99] by injection molding. PEI could be readily imbibed with various volatile organic compounds such as chlorinated hydrocarbons [100] and acetone [101]. 

Results of some of these short-term tests are shown in Table II. A comparison is given between PPS and five other plastics nylon (Zytel 101), polycarbonate (Lexan 141), polysulfone (Bakelite Polysulfone), polyphenylene oxide (Noryl), and polyetherimide (Ultem 2300). The data presented are based upon retention of tensile strength for all plastics except the Ultem 2300, which is based upon retention of flexural strength. Unsuccessful attempts were made to injection mold ASTM Type IV tensile bars out of the Ultem compound, but flexural strength bars could be made. Experience has shown that chemical resistance tests monitored by flexural strength retention are comparable to those monitored by retention of tensile strength. 

Polyetherimide (Ultem 1000, GEC) is a high performance engineering thermoplastic with high heat distortion temperature (> 200°C), high mechanical strength and inherent flame-retardancy characteristics. Recently blends of polyetherimide with polycarbonate have been commercially offered as thermoformable sheets and as molding compounds (Table 15.28). The primary reason for... 

Volatile compounds were found to penetrate into polyetherimide resins. Chemical moieties such as bromine, iodine, hydrofluoric acid, hydrochloric acid, hydrobromic acid, ammonia, hydrazine, triethylamine, formaldehyde, formic or acetic acid, trifluoroacetic acid, and nitric acid were examined. The use of these chemical impregnators to augment the mechanical component was investigated. In addition to being volatile, candidate materials had to either etch the polyetherimide surface or interact with subsequent species to etch the... 

Polyetherimide molding compounds are commercially available in extmsion and injection molding grades. The major suppliers of this material include GE Plastics (JJltem), Compound Technologies, DSM Engineering, LNP, and RTF A polyether-imide-polycarbonate alloy and a polyetherimide-silicone alloy are also available from GE Plastics. 

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. 

Global demand staged a modest recovery in 2002, with an estimated growth rate of 5.2%. For the period 2002-2007, world polyetherimide consumption is projected to increase at a compound... 

Automotive is by far the largest market for polyetherimide, representing 50% of total world volume in 2002. Polyetherimide usage in automotive applications has been increasing in recent years due to its replacement of metal, thermosets and bulk moulding compounds (BMC). There is still scope for further use of PEI in car electrical and under-the-boimet applications, which will underpin good growth prospects. 

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