We successfully formed an inclusion complex between nylon-6 and R-cyclodextrin and attempted to use the formation and subsequent disassociation of the nylon-6/R-cyclodextrin inclusion complex to manipulate the polymorphic crystal structures, crystallinity, and orientation of nylon-6. Formation of the inclusion complex was verified by Fourier transform infrared (FTIR) spectroscopy, wideangle X-ray diffraction (WAXD), differential scanning calorimetry (DSC), and CP/MAS 13 C NMR. After obtaining the inclusion complex of nylon-6 and R-cyclodextrin, the sample was treated in an acid environment to remove the host R-cyclodextrin and coalesce the nylon-6 guest polymer. Examination of as-received and IC coalesced nylon-6 samples showed that the R-form crystalline phase of nylon-6 is the dominant component in the coalesced sample. X-ray diffraction patterns demonstrate that the γ-form is significantly suppressed in the coalesced sample. Along with the change in crystal form, an increase in crystallinity of ∼80% was revealed by DSC, and elevated melting and crystallization temperatures were also observed for the coalesced nylon-6 sample. FTIR spectroscopy revealed a significant degree of orientaion for the nylon-6 chains coalesced from their R-cyclodextrin inclusion complex crystals. Thermogravimetric analysis indicated that nylon-6 has an ∼30 °C higher thermal degradation temperature after modification by threading into and being extracted from its R-cyclodextrin inclusion complex.

Melting parameters are reviewed for the nitrates of Li, Na, K, Rb, Cs and Ag, and are com­pared with values for the corresponding halides. Previously published information has been supplemented by experiments on the viscosity of molten AgNO 3 , and on the dilatometry and electrical conductivity of AgNO 3 in the solid and melt. It is suggested that the low melting points of group I nitrates, compared with the corre­sponding halides, is due to the formation of association complexes in the nitrate melts. This process could contribute a term to the overall entropy of fusion S f without greatly increasing the heat of fusion H f . Since T f = H f / S f , this would explain the unusually low melting points. The small volume changes of fusion of nitrates, where measured, and the abnormal activation energies for the viscosities of molten nitrates, support the suggested mechanism of melting.