Blends with Thermoplastic Imides

The Michael addition reaction of dimercaptodiphenylether with N-(3-ethynyl phenyl) maleimide allowed the synthesis of ethynyl-terminated imido-thioether as shown in Fig. 50 (139). This acetylene terminated imidothioether was blended with acetylene terminated polyarylene ether oligomers of different molecular weights and tested as composite resins (140). Blends of functionalized thermoplastics such as the acetylene terminated polyarylene ethers with brittle high-Tg imide resins are finding increased attention for tough high-Tg composites. 

An aromatic polymer containing both ether and imide groups in the polymeric chain. It has a heat distortion temperature of 200 °C, continuous use temperature of 170 °C, and low flammability. It can be blended with several engineering thermoplastics for a wide range of properties and applications (mainly in automotive and electronic/electrical industries). 

Owing to these superior performances of DESs in polymer synthesis, in 2012, Fernandes reported the electrochemical synthesis of conducting polymers (polyaniline) in the eutectic mixture ChCl/EG " Ramesh and co-workers have also described other conducing polymers composed of cornstarch or cellulose acetate, mixed with lithium bis(trifluo-romethanesulfonyl)imide and the deep eutectic solvent ChCl/Urea. " " Finally, Leroy et al. used the eutectic mixtures ChCl/Urea and ChCl/Gly as functional additives to develop an efficient polymer blend of thermoplastic starch. " ... 

Polyamide-imides (PAIs) are thermoplastic amorphous polymers prepared by the condensation of an aromatic diamine, such as methylene diamine, and an anhydride, such as trimellitic add chloride. PAIs have good mechanical, thermal, chemical resistance, high strength, melt processability, and high heat capacity. They can be processed into a variety of forms, such as injection or compression molded articles, coatings, films, fiber, and adhesives. The typical heat deflection temperature for neat molded PAI is 278°C,but reinforcements are often used to improve mechanical properties. PAIs are generally soluble in strong aprotic solvents such as NMP and DMAc, and thus misdble blends with PBI are feasible. 

A mixture of a BMI (Compimide 796) with 4,4 -bis(orf/zo-propenylphe-noxy)benzophenone (TM 23) was blended in solution with Udel 700 (polysul-fone from Union Carbide), Ultem 100 (General Electric polyether imide), and PH 10 (Bayer polyhydantoin) (Fig. 35). The thermoplastics were introduced at various concentrations up to 33%. A phase segregation did not appear with PH 10, but two phases were observed with Ultem. With both semi-IPNs the observed Glc were found to be four- to fivefold the Glc of the neat BMI [113]. 

PEEK is miscible with poly(ether imide) (PEI). PEI is less expensive than PEEK it is used as an amorphous thermoplastic. The kinetics of crystallization and other properties of such blends have been presented in the literature. 

The evolution of viscosity with regards to blend composition is shown in Figure 4.3. Viscosity was shown to correspond well with the three types of typical phase stmeture, namely phase dispersion, bicontinuous and phase-inversion morphology in thermoplastic-modified thermoset systems. Before phase separation, the homogeneous mixture behaved as a semidilute polymer solution, and the viscosity increased in line with the poly(ether imide) concentration. However, on phase decomposition, tj was shown to increase or decrease abmptly, depending on the morphology variation. 

St. Clair et used the concept of sequential semi-IPNs to produce two unique IPNs which are based on acetylene-terminated imide oligomers and thermoplastic polyimides, particularly a material designated LARC-TPI. Pater and others used the concept of simultaneous semi-IPNs to make semi-IPNs which are based on PMR-15 mixed with such materials as LARC-TPI, NR150B2 and Thermid 600 polyimides. Other examples of semi-IPNs which fit into the category of high temperature materials include thermoplastic modified bismaleimides (BMI). As one example, BMI has been mixed with condensation polyimides such as PI20280 or with terminated poly (arylene ether ketone) oligomers. The observed miscibility in semi-IPNs which are based on thermoplastic BMIs was found to be further improved when a BMI and thermoplastic both prepared from aromatic diamines were blended. ... 

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