2H NMR spin relaxation study of the soft segment motion in alternating ethylene–propylene copolymers
✍ Scribed by Takeshi Nakajima; Tsutomu Akiyama; Hidemine Furuya
- Publisher
- John Wiley and Sons
- Year
- 2002
- Tongue
- English
- Weight
- 91 KB
- Volume
- 40
- Category
- Article
- ISSN
- 0749-1581
- DOI
- 10.1002/mrc.985
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✦ Synopsis
We synthesized three partially deuterated polymer samples, namely a poly(ethylene-alt-propylene) (EP) alternating copolymer, a poly(styrene-b-EP) diblock copolymer (SEP) and a poly(styrene-b-EP-b-styrene) triblock copolymer (SEPS). The 2 H spin-lattice relaxation time, T 1 , of EP soft segments above their glass transition temperature was measured by solid-state 2 H NMR spectroscopy. It was found that the block copolymers had a fast and a slow T 1 component whereas EP copolymer had only a fast component. The fast T 1 components for SEP and SEPS are similar to the T 1 value of EP above ca 20 • C. The slow T 1 component for SEP and SEPS exhibited a minimum at 60 • C and approached the value of the fast component near the T g of polystyrene. The motional behavior of the EP units for SEP is similar to that of SEPS over the entire range of temperature.