STUDY OF THE INCLUSION-COMPOUNDS FORMED BETWEEN ALPHA-CYCLODEXTRIN AND HIGH-MOLECULAR-WEIGHT POLY(ETHYLENE OXIDE) AND POLY(EPSILON-CAPROLACTONE)

We report the formation of high molecular weight polymer inclusion com pounds (ICs) between cr-cyclodextrin and poly(ethylene oxide) (PEO) (M -n = 100 kg mol(-1)), and poly(epsilon-caprolactone) (PCL) (M-n = 40 k g mol(-1)). Both high molecular weight polymer ICs were successfully m ade by ultrasonic and heating techniques. Dsc, tga, X-ray diffraction, FTi.r. and solid state C-13 n.m.r. were utilized to observe the PCL a nd PEO polymer chains included inside the channels formed by ol-cyclod extrin. Dsc and tga scans showed that the high temperature stable poly mer-CD-IC samples contain no free crystalline polymer. The much higher decomposition temperatures observed for these polymer-CD-ICs may impl y that polymer chains included inside the polymer CD-IC channels can g reatly improve cyclodextrin's stability. The polymer-CD-IC's X-ray dif fraction patterns were very similar to that of valeric acid-CD-IC, whi ch is confirmed to be a channel crystal structure, and the strong peak for both polymer-CD-ICs at approximately 20.0 degrees (2 theta) may c onfirm their IC formation. New bands appeared at 1729 cm(-1) for PEO-C D-IC and at 1739 cm(-1) for PCL-CD-IC in their FTi.r. spectra. Both ba nds were absent from the alpha-cyclodextrin spectrum. In CP/MAS/DD C-1 3 n.m.r. spectra, single resonances for PEO-CD-IC, which compared with the multiple resonances observed for each carbon type in cr-cyclodext rin, may indicate that or-cyclodextrin adopts a more symmetrical cycli c conformation in the PEO-CD-IC sample, while pure alpha-cyclodextrin assumes a less symmetrical conformation in the crystal when it does no t include a guest polymer PEO inside its cavity. A one-pulse C-13 n.m. r. spectrum was observed to identify the resonance peak for PEO inside the PEO-CD-IC. (C) 1998 Elsevier Science Ltd. All rights reserved.