Synthesis and characterization of new soluble and thermostable polyimides via novel diisocyanates

Abstract

A facile synthesis of two novel diisocyanates containing methylene groups and preformed imide structure is described. Furthermore, six thermally stable and soluble polyimides were synthesized by polycondensation of these two diisocyanates with pyromellitic dianhydride (PMDA), 3,3′,4,4′‐benzophenonetetracarboxylic dianhydride (BTDA) and hexafluoroisopropylidene‐2,2‐bis‐(phthalic anhydride) (6FDA) in N,N‐dimethyl acetamide. All monomers and polymers were characterized by conventional methods and their physical properties such as solution viscosity, solubility properties, thermal stability and thermal behaviour were studied. © 1999 Society of Chemical Industry

Effect of sepiolite nanoparticles on the properties of novel poly(sulfone ether imide)

“…Polyimides (PIs) are well known as an important class of heat‐resistant polymers in addition to a combination of many desirable physical, mechanical, and optical properties …”

Synthesis and properties of new aromatic polyimides based on 2,2′‐dibromo‐4,4′,5,5′‐benzophenone tetracarboxylic dianhydride

“…Therefore, a lot of research work has been focused on the improvement of the solubility and processability of polyimides in fully imidized form, while maintaining thermal stability and high‐temperature mechanical properties, which are characteristic of aromatic polyimides. Of the various alternatives to design novel processable polyimides, some universally adopted approaches are as follows: a) introduction of aliphatic or other flexible segments, which reduce chain stiffness;6–12 b) incorporating a large polar or non‐polar pendent bulky group along the polymer backbone, which reduces the inter‐chain interactions by eliminating the charge‐transfer complex between chains through steric hindrance and also hinders molecular packing and crystallization;13–16 c) use of enlarged monomers containing angular bonds, which suppress coplanar structures;17, 18 and d) use of 1,2‐ or 1,3‐substituted, instead of 1,4‐substituted monomers, and/or asymmetric monomers, which lower regularity and molecular ordering 19, 20…”

Preparation of novel pyridine‐based, thermally stable poly(ether imide)s

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