Polyetherimide, mechanical properties

Connectors, switches, electric distributors, fuse boxes and other electric fittings need a subtle balance of electrical and mechanical properties, durability, cost and aesthetics. This broad field creates fierce competition not only between engineering thermoplastics and SMC/BMC for the main applications but also with polypropylene and polyethylene or PVC for the lower performance parts and, at the opposite end of the scale, with high-tech plastics such as polyetherketone, polyetherimide, liquid crystal polymers. .. For example, without claiming to be exhaustive ... 

The mechanical properties are good with medium to low elongations at break and more limited strains at yield. Moduli and hardnesses are in a high range but notched impact strengths are in a medium range. Polyetherimide displays notch sensitivity and stress concentrators must be avoided when designing. 

Polyetherimide poly(2,2 -bis(3,4-dicarboxyphenoxy)phenylpropane)-2-phe-nylenediimide) (PEI) is a commercial engineering thermoplastic with excellent mechanical properties and high thermal stability. 

Gir Girard-Reydet, E., Vicard, V., Pascault, J. P., Sautereau, H. Polyetherimide-modified epoxy networks Influence of cure conditions on morphology and mechanical properties. J. Appl. Polym. Sci. 65 (1997) 2433-2445. 

D. G. Baird, S. S. Bafna, J. P. DeSouza, and T. Sun, Mechanical properties of in situ composites based on partially miscible blends of polyetherimide and liquid crystalline polymers, Polymer Composites, vol. 14, No. 3, 214-223, June (1993). 

Like the pultrusion process, the selection of a suitable thermoplastic matrix material mainly depends on the desired mechanical properties and the desired long-term service temperature. The range of usable matrix materials starts with standard polymers such as polyethylene (PE) or polypropylene (PP) and ends with high performance polymers such as polyetherimide (PEI) or poyletheretherketone (PEEK). Recent developments have shown that the processing of reactive thermoplastic materials is possible as well (CBT). For some physical properties of common matrix materials see Table 8.2. °... 

Polyetherimide and epoxy resins Mechanical properties and electrical conductivity 24... 

Crystallinity is key to the development of mechanical properties and good chemical resistance. It is what differentiates PARK from cheaper, but higher Tg, amorphous materials such as polyethersulfones and polyetherimides. 

Improved extrusion conditions are expected to provide enhancements of montmorillonite alignment in the polyetherimide and possibly improved dispersion and exfoliation efficiency with subsequent improvement in mechanical properties. 

Amorphous materials are random entanglements of pol5mer chains, known for very good mechanical properties (strength, stifi iess) and dimensional performance. Amorphous polymers include ABS, polycarbonate, PPO/PPE, polyphenylene sulfone, polyethersulfone, polysulfone and polyetherimide. 

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