Session C1 - Poster Session I.
POSTER session, Monday afternoon, March 22
, Palais des Congres
Polyolefin copolymers of diblock (poly)(syndio-)propylene-b-ethylene- propylene and triblock (poly)(syndio-)propylene-b-ethylene-propylene-(syndio-)propylene were synthesized using new living single site titanium catalyst. The phase diagram was established and interesting morphology was observed in the microphase-separated domains where both polypropylene (PP) and ethylene-polypropylene (EP) layers were semicrystalline. Crystallinity of the copolymers was determined and mechanical properties such as stress-strain and stress relaxation behaviors were examined to observe fracture stress and strain, Young modulus and mechanical hysteresis at different temperatures. It was found that molecular structures strongly affect the mechanical properties of the copolymers. Increasing molecular weight improves the ductility of the copolymers and increasing PP content increases Young modulus and the plastic strain after deformation. Higher ethylene content in EP block produces a higher fracture stress even in the weak diblock copolymers. We will discuss these interesting mechanical characteristics in terms of the semicrystalline microstructures of the copolymers.