Glass transition temperatures, poly amide

Fluorinated poly(imide-ether-amide)s are readily soluble in organic solvents like dimethylformamide (DMF), N-methylpyrrolidone (NMP), pyridine or tetrahydrofu-ran (THF) and give flexible films by casting of such solutions. These polymers exhibit decomposition temperatures above 360°C, and glass transition temperatures in the 221-246° C range. The polymer films have a low dielectric constant and tough mechanical properties. 

Glass-transition temperatures (K) of poly(amide imides) derived from trimellitic anhydride (see structure above)... 

Isosorbide, a double dehydration product derived from sorbitol, is an attractive monomer due to its rigidity, chirality, and non-toxicity. Various isosorbide-based polymers have been synthesized by condensation polymerization, including polyesters, polyamides, poly(ester amides), polycarbonates, and polyurethanes. Incorporation of isosorbide into polymers backbones will introduce special properties, such as enhanced glass transition temperatures and/or optical properties. 

Polyhydrazides and poly(amide-hydrazide)s with redox-active carbazole and triphenylamine units have been synthesized [49]. The resulting poly( 1,3,4-oxadiazole)s andpoly(amide-l,3,4-oxadiazole)s show high glass transition temperatures of 288-330 °C and a high thermal stability. The polymers show a weak to medium photoluminescence with emission maxima of 474-506 nm. In addition, the materials show an enhanced redox stability and electrochromic performance. 

Acetic anhydride and pyridine can be added as reaction catalysts for imidization of the poly(amide amic acid) if desired. The glass transition temperature of the PAIs is 270-320 °C. The density of the foams is 0.1-0.5 g cm . Table 14.3 shows the properties of the final materials dependent on the degree of imidization. 

Flexure Mode. Figure 29 illustrates TMA data for a two-layer insulation wire coating. Using the knife-edged three-point bend flexure probe (67) accentuates the softening that occurs at the glass-transition temperature. It is remarkable that the softening of both the outer layer of polyester and the inner layer of poly(amide-imide) were easily detected. 

For the polycondensation of 4,4 -(hexafluoroisopropyli-dene)-N,N -bis(phthaloyl-L-leucine) diacid chloride with aromatic amines, higher glass transition temperatures (ca. 19-82 °C) were reported. A similar series of poly(amide imidejs were obtained by the polycondensation of diacid chlorides such as [N,N -(4,4 -carbonyldiphthaloyl)] bis-isoleucine diacid chloride, N,N (4,4 -carbonyldiphthaloyl)-bis-/-phenylalanine) diacid chloride, and N,N - (4,4 -... 

---