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The blend surface of polyamide 6 and polytetrafluoroethylene (PA 6/ PTFE) and its change as a function of annealing time are investigated by means of attenuated total reflection (ATR)-FTIR spectroscopy, contact angle (CA) measurement, as well as atomic force microscopy (AFM) under ambient condition; meanwhile the surface elemental compositions are obtained by X-ray photoelectron spectroscopy (XPS). The results show that the addition of fluoro content can decrease the surface energy compared with the pure polyamide, while, an evident influence on the surface energy has not been detected with increasing fluoro contents. Upon annealing at 120 8C, there is a profound enrichment of the low-surface energy component to the sample surface; yet this situation becomes more complex when samples are annealed at 150 8C-not only the segregation effect from the low surface energy PTFE, but also the crystallization of the PA 6 will come into play for the blend with 50% PTFE. These observations are ascribed to the presence of the polar group of the polyamide component, as well as its strong tendency to crystallize when subjected to thermal treatment at sufficiently high temperatures, and this behavior would basically offset the segregation tendency of fluoro component to the sample surface. This assumption is further corroborated by the XPS measurement in the current researches. V V C 2006 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 45: 138-152, 2007

Composites comprised of chitosan (CS) and multiwalled carbon nanotubes (MWCNTs)were fabricated by milling and ultrasonication dispersion methods. Scanning electron microscopy images showed homogeneous dispersion of MWCNTs throughout the CS matrix for samples prepared by either ultrasonication or milling methods. Further, the crystallinity of the CS component was found to decrease with the addition of MWCNTs, although the decomposition temperature and the storage modulus (E ) of the samples were improved. The decomposition temperature for the composite prepared by milling was 7 • C higher than that by the ultrasonication. Meanwhile, the E decreased relatively slowly with temperature in the dynamic mechanical analysis measurements. In addition, IR analysis implied an interaction between CS and MWCNTs, which likely originated from hydrogen bonds between the amino, hydroxyl, and carboxyl groups of the two components. Compared with the ultrasonication, milling was more effective to promote the formation of the hydrogen bonds between CS and the MWCNTs and thus enhance the thermal stability of CS.