Single-Component Polymer Composites

Noncovalently bonded crystalline inclusion compounds (ICs) have been formed by threading host cyclic starches, cyclodextrins (CDs), onto guest nylon-6 (N-6) chains. N-6 was coalesced from N-6-alpha-CD-IC crystals by appropriate removal of the host alpha-CD. When added at low concentrations, the coalesced N-6 serves as an effective self-nucleating agent for the bulk crystallization of N-6 from the melt. Film sandwiches consisting of two layers of as-received, and one layer each of as-received and self-nucleated N-6 were produced by melt pressing. DSC and tensile tests were conducted on these films. As-received and self-nucleated films have their own characteristic crystallization behaviors, and the film sandwich composed of one layer each of as-received and self-nucleated N-6 show a combination of the component melt-crystallization DSC peaks, indicating that both films maintain their characteristic structures and properties even after melt-processing them into a sandwich composite. This result clearly shows that we have a composite and not a single phase material and is supported by SEM images of the composite sandwich cross section. Furthermore, when compared to the film sandwich made with two layers of as-received N-6 film, the composite as-received/self-nucleated film sandwich shows superior mechanical properties.