화학공학소재연구정보센터
Journal of Polymer Science Part A: Polymer Chemistry, Vol.36, No.1, 31-38, 1998
New polymer syntheses. XC. A-B-A triblock copolymers with hyperbranched polyester A-blocks
Telechelic oligo(ether-ketone)s containing two trimethylsiloxy end groups and one methyl group per repeating unit were prepared by polycondensation of 4-fluoro-2'-methyl-4'-(trimethylsiloxy)benzophenon. The telechelic character was achieved by cocondensation of a small amount of silylated bisphenol-P. The end groups of the silylated oligo(ether-ketone)s were acetylated by means of acetyl chloride. On the basis of H-1-NMR end group analyses two samples of alpha,omega-bis(acetoxy) oligo(ether-ketone)s with DP = 14 and DP similar to 28 were obtained. These oligo(ether-ketone)s and a 70 or 140 fold molar amount of silylated 3,5-bis(acetoxy) benzoic acid were polycondensed at 270 degrees C in bulk. The resulting A-B-A triblock copolymers were fractionated by dissolution in tetrahydrofuran. In three out of four experiments a small fraction of precipitated material rich in oligo(ether-ketone) was isolated. The purified triblock copolymers were characterized by inherent viscosities and NMR spectra. For those samples containing the long oligo(ether-ketone) block a low degree of crystallinity was observed after annealing. Four additional polycondensations were conducted with an initial reaction temperature of 290 degrees C. In this way a completely soluble and amorphous triblock copolymer was obtained.