Inclusion compounds formed between cyclodextrins and nylon 6

High performance properties are increasingly needed in fibers for industria l applications. Such properties have been achieved in both flexible and int rinsically stiff polymers, but only through specialized and expensive spinn ing methods. In this work the potential of achieving high performance mecha nical behavior in nylon 6 using a conventional spinning process was explore d. We report the formation of high-molecular-weight polymer inclusion compo unds (ICs) between alpha and beta-cyclodextrins (alpha- and beta-CDs) and n ylon 6 (M-n = 12 kg mol(-1)). Both high-molecular-weight polymer ICs were s uccessfully made by a heating technique. Differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), wide-angle X-ray diffraction (WAXD ), and Fourier transform infrared (FTIR) spectroscopy have been utilized to observe the nylon 6 polymer chains included inside the channels formed by the cyclodextrins. DSC and TGA scans showed the high-temperature stable nyl on 6-CD-IC samples contain no free crystalline nylon 6 polymer, and the muc h higher decomposition temperatures observed for these nylon-CD-ICs may imp ly that polymer chains included inside the polymer CD-IC channels can great ly improve cyclodextrins' stabilities. The nylon 6-alpha-CD-IC and nylon 6- beta-CD-IC X-ray diffraction patterns were very similar to those of valeric acid-alpha-CD-IC and 1-propanol-beta-CD-IC, which were confirmed to be cha nnel crystal structures by single crystal X-ray diffraction. A new band whi ch was absent from the pure cyclodextrin spectrum appeared at 1729 cm(-1) f or nylon 6-CD-ICs in their FTIR spectra and may be characteristic for CDs i n their channel-forming ICs. (C) 1999 Elsevier Science Ltd. All rights rese rved.