Optically high transparency and light color of organosoluble fluorinated polyamides with bulky xanthene pendent groups
(2523–2532)Polymers for Advanced Technologies 22 #12 (2011)
Sheng et al of Jiangxi Normal University, China, prepared new fluorinated polyamides directly from a diamine, 9,9-bis[4-(2-trifluoromethyl-4-aminophenoxy)phenyl]xanthene (BTFAPX) with various aromatic dicarboxylic acid chlorides by low-temperature polycondensation.  The polymers were produced with moderate-to-high inherent viscosities of 0.65–1.01 dl/g while the weight-average molecular weight and number-average molecular weight were in the range of 69,000–82,000 and 39,000–43,000, respectively. Nearly all the polymers were readily soluble in amide-type polar aprotic solvents [e.g. N, N-dimethylacetamide (DMAc) and N-methyl-2-pyrrolidinone], and even in less polar solvents such as dimethyl sulfoxide and pyridine, and afforded transparent, light-colored, and flexible films upon casting from DMAc solvent. The polymers showed glass transition temperatures between 235 and 284°C, and 10% weight loss temperatures ranging from 495 to 532°C and 476 to 510°C in nitrogen and air, respectively, and char yields higher than 55% at 800°C in nitrogen. All polymers were amorphous and their films exhibited tensile strengths of 64–95 MPa, elongations at break of 6–9%, and tensile moduli of 1.9–2.5 GPa. These polymers had dielectric constants ranging from 3.65 to 4.03 (100 Hz), low-moisture absorption in the range of 0.56–1.14%, and high transparency with an ultraviolet–visible absorption cut-off wavelength in the 334–372 nm range. (RDC 11/25/2011)