Synthesis and properties of thermoplastic elastomers based on PTMO and tetra-amide

Segmented copolymers based on T6T6T-dimethyl (two-and-a-half repeating unit of nylon-6,T) and PTMO or extended PTMO1000/DMT that are thermoplastic elastomers were made via polycondensation. The materials have a good solvent resistance, are melt-processable and transparent. The polymers all have a low glass transition temperature (-60 to -0 degreesC). The rubbery plateau is wide and extremely flat and the melting temperature is sharp and high. The shear modulus of the rubbery plateau (3.3-14.5 MPa) and the flow temperature (183-220 degreesC) increase with increasing T6T6T content (5-16 wt%), corresponding to increasing crystallinity. The undercooling, as measured by DSC, is 20-30 degreesC. The compression set at room temperature is low (6-7%) and decreases slightly with decreasing T6T6T content. With AFM it was shown that the crystalline T6T6T units form long threads or ribbon like structures with a high aspect ratio in the amorphous PTMO matrix. (C) 2003 Elsevier Ltd. All rights reserved.