Poly imide toughness

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. 

There is much interest in the formation of blends of poly(imide)s with other polymers, so as to improve properties such as toughness and processability [14-19, 58, 59]. The subject of measurement of interactions and miscibility of blends by NMR spectroscopy has been discussed by Takagoshi and Asano in Chapter 10 of this book, and will not be referred to in detail here. The use of NMR to study miscibility in blends containing poly(imide)s is somewhat restricted because most poly(imide)s contain a high proportion of aromatic groups, and consequently form blends with other highly aromatic polymers. The CPMAS spectra, which as discussed above are broad and... 

Poly(amide imide) Toughness, good mechanical strength ... 

Recently siloxane-imide copolymers have received specific attention due to various unique properties displayed by these materials which include fracture toughness, enhanced adhesion, improved dielectric properties, increased solubility, and excellent atomic oxygen resistance 1S3). The first report on the synthesis of poly(siloxane-imides) appeared in 1966, where PMDA (pyromellitic dianhydride) was reacted with an amine-terminated siloxane dimer and subsequently imidized 166>. Two years later, Greber 167) reported the synthesis of a series of poly(siloxane-imide) and poly(siloxane-ester-imide) copolymers using different siloxane backbones. However no physical characterization data were reported. 

Inherent viscosities (Tiinh) of the poly(amic acid)s were as low as 0.08-0.23, however, they formed flexible and tough films. In the IR spectra of nonaromatic polyimides, characteristic imide absorptions at 1767 cm"1 (asym C=0 str.) and 1699-1703 cm 1 (sym C=0 str.) were observed, and the absorptions of amic acid groups have practically disappeared. 

Jan Jang, J.-S., Shin, S.-H. Toughness improvement of tetrafunctional epoxy resin by using hydrolysed poly (ether imide). Polymer 36 (1995) 1199-1207. 

Gen Gensler, R., BegueUn, P., Plummer, C. J. G., Kausch, H.-H., Mtinstedt, H. Tensile behaviour and fracture toughness of poly (ether ether ketone)/poly (ether imide) blends. Polym. Bull. 37... 

R. Gensler, Ph. Biiguelin, C. J. G. Plummer, H.-H. Kausch, and H. Miinstedt. "Tensile behaviour and fracture toughness of polyfether ether ketone)/ poly(ether imide) blends." Polymer Bulletin, pp. 111-118,1996. 

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