The mechanical behavior of propylene−pentene isotactic copolymers synthesized with a single-center organometallic catalyst in a broad interval of pentene (Pe) concentration, from 3 to 50 mol %, is analyzed. All copolymers show flexible behavior with very high deformation at breaking. The presence and entrance of Pe counits in α and δ forms of isotactic polypropylene (iPP) transform a strong and fragile iPP homopolymer into ductile and flexible materials. The stress at yield decreases as the Pe content increases, but a different behavior has been observed for samples in the α form or in the δ form. In samples in the α form, from 3 to 8.8 mol % of Pe, the stress at yield increases as the thickness of crystalline lamellae increases, while in samples in the δ form containing higher Pe counits, it decreases as the thickness of lamellae increases and Pe content increases. Phase transition of the α form in the mesophase and crystallization of the δ form, in samples with 8−11 mol % of Pe, occur upon deformation and are correlated to the strain-hardening observed at high strain.
Mechanical Properties and Morphology of Propene-Pentene Isotactic Copolymers / De Rosa, Claudio; Scoti, Miriam; Auriemma, Finizia; Ruiz De Ballesteros, Odda; Talarico, Giovanni; Malafronte, Anna; Di Girolamo, Rocco. - In: MACROMOLECULES. - ISSN 0024-9297. - 51:8(2018), pp. 3030-3040. [10.1021/acs.macromol.8b00362]
Mechanical Properties and Morphology of Propene-Pentene Isotactic Copolymers
De Rosa, Claudio;Scoti, Miriam;Auriemma, Finizia;Ruiz De Ballesteros, Odda;Talarico, Giovanni;Malafronte, Anna;Di Girolamo, Rocco
2018
Abstract
The mechanical behavior of propylene−pentene isotactic copolymers synthesized with a single-center organometallic catalyst in a broad interval of pentene (Pe) concentration, from 3 to 50 mol %, is analyzed. All copolymers show flexible behavior with very high deformation at breaking. The presence and entrance of Pe counits in α and δ forms of isotactic polypropylene (iPP) transform a strong and fragile iPP homopolymer into ductile and flexible materials. The stress at yield decreases as the Pe content increases, but a different behavior has been observed for samples in the α form or in the δ form. In samples in the α form, from 3 to 8.8 mol % of Pe, the stress at yield increases as the thickness of crystalline lamellae increases, while in samples in the δ form containing higher Pe counits, it decreases as the thickness of lamellae increases and Pe content increases. Phase transition of the α form in the mesophase and crystallization of the δ form, in samples with 8−11 mol % of Pe, occur upon deformation and are correlated to the strain-hardening observed at high strain.File | Dimensione | Formato | |
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