The molecular mobility at the interface of poly(dimethylsiloxane) [PDM
S]/nylon-6 block copolymers was investigated using dynamic mechanical
analysis (DMA) and solid-state deuterium NMR. Using DMA, T-g depressio
n of the nylon matrix was observed with increasing PDMS content, and t
he mechanical loss peaks were broadened to lower temperature. When the
room-temperature line spectra of solid-state deuterium NMR were compa
red for nylon-6 homopolymer and PDMS/nylon-6 diblock copolymer, a dear
difference was observed; a peak associated with highly mobile nylon w
as observed in the block copolymer spectrum. This high mobility peak.
was observed even at -50 degrees C. Using a selectively deuterated tri
block copolymer, the origin of this peak mas shown to arise from a she
ll of softened nylon in the vicinity of PDMS domains. This softening e
ffect was lost at -80 degrees C where PDMS domains can crystallize. Th
is softened shell is not only from the compositionally mixed interfaci
al zone but also from a fraction of the pure nylon region surrounding
the interfacial zone.