Synthesis and evaluation of novel polyimides derived from spirobichroman diether anhydride

A strategy for preparing spirobichroman dianhydride from bisphenol A and its resulting polyimide with low dielectric characteristic

“…7(a) shows the TMA thermogram of SBC-DDM. The T g value, dened by on onset temperature of the TMA thermogram, is 343 C. On the other hand, the T g value of the referenced PEI 7f is 235 C, 16 demonstrating that the higher rigidity of diether-free SBC-DDM contributes to the improved thermal properties. The coefficient of thermal expansion (CTE) of SBC-DDM in the temperature range of 50-150 C is around 41 ppm C À1 , suggesting a remarkable dimensional stability at low temperature.…”

“…This is due to the incorporation of hydrophobic chroman and methylene units in SBC-DDM. When compared with the diether and spirobichroman-containing polyetherimide 7f (the structure is shown in Table 3), 16 diether-free SBC-DDM exhibits superior organo-solubility (Table 3).…”

“…15 Hsiao et al extended two kinds of spirobichroman diol (1)- (2) to spirobichroman dietheramines (3)-(4) and dietheranhydride (5), respectively (Scheme 1). [16][17][18] Spirobichroman and diether-containing polyetherimides (PEIs) were further prepared, showing excellent organo-solubility. [16][17][18] However, the T g values of these PEIs are in the range of 175-280 C. Obviously, the diether linkages reduced the rigidity of polymer chains, leading to only moderate T g s.…”

The role of leukotrienes in alveolitis associated with scleroderma

“…Polyimides containing ether linkages prepared through phenoxy derivatives via nitro displacements, especially General Electric's poly(ether imide) Ultem®, have achieved great commercial success 6, 7. On the other hand, the introduction of bulky groups into the polymer chain8–16 or the attachment of bulky lateral groups17–27 can impart a significant increase in the glass‐transition temperature ( T g ) by restricting the segmental mobility while providing good solubility from decreased packing and crystallinity. Combining these two structural modifications minimizes the trade‐off between the poor processability and the improved physical properties of aromatic polyimides.…”

Preparation and properties of novel polyimides derived from 4‐aryl‐2,6 bis(4‐amino phenyl)pyridine

“…Consequently, the preparation of new polyimides with better processability (and maintained thermal stability) has been a major research topic. To overcome these shortcomings, various noteworthy attempts have been made with the aim of synthetic modification of the rigid‐chain structure—first, by the introduction of flexibilizing linkages into the main chain that generally lead to a lower glass‐transition temperature ( T g ) as well as a significant improvement of the solubility and thermoplasticity of polymers,7–10 and second, by the introduction or the attachment of bulky groups11–22 into the polymer main chain that impart a significant increase in T g by restricting the segmental mobility and providing a good solubility as a result of decreased packing and crystallinity.…”