Structure and Properties of Supermolecular Elastomer Formed by Telechelid Polymer and Crystalline Amines

点击翻译按钮获取中文摘要

Characterization of carboxyl-terminated telechelic poly(ethyrene-butylene)(CTPEB) was performed by NMR, GPC, small angle neutron scattering (SANS), and FT-IR. It was clarified that this sample has M_n=2000 and almost 100% telechelic. CTPEB sample was neutralized by octadecylamine (ODA) by two methods, i.e., via solution and melt blending and confirmed that the neutralized samples by both methods have practically the same structure and physical properties. A series of sample with different molar ratio of COOH and NH_2 were prepared and their structure and viscoelastic properties at around room temperature (ca 25 ℃) and elevated temperature (65 or 70℃) were examined. The 1: 1 blend sample did not show elastic behavior at all. When excess ODA was added, the system was elastic substance at low temperature and viscoelastic liquid at high temperature. The transition was reversible. From DSC, XRD, FT-IR analysis, it was revealed that most of ODA are non-crystalline. From SANS measurements, sc … More attering curve similar to aluminum tristearylate/decalin system, which was examined as a reference system and became clear that its viscoelastic behavior is due to entangled wormlike micelle structure generated by aggregation of C_18 residue. Therefore, it was concluded that the elastic behavior of CTPEB/ODA is also due to the network structure generated by aggregation of C_18 residue. Strength of the network structure was examined by strain sweep measurement and found that this system shows plastic flow at low strain (ca. 10%). This value is close to the values obtained for ionomers, which was prepared by neutralization of CTPEB with multivalent metal ions.From the value of plateau modulus, it was speculated that only 10 % of poly(ethyrene-butylene) molecules take bridge conformation while others become loop or dangling ends.When amino residue is replaced by amide, there was only a slight increase of transition temperature. Other model alkanes having polar residues, they showed poor miscibility with CTPEB. On the other hand, their crystalline structure and structural transition are very interesting which can be studied as model system for crystalline polymers. Less