Dielectric and thermal characterization of low density ethylene/10‐undecen‐1‐ol copolymers prepared with nickel catalysts |
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| Authors: | M Teresa Viciosa Carla Rodrigues Susete Fernández Inês Matos Maria M Marques M Teresa Duarte João F Mano Madalena Dionísio |
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| Institution: | 1. REQUIMTE, Departamento de Química, Faculdade Ciências e Tecnologia, Universidade Nova de Lisboa, 2829‐516 Caparica, Portugal;2. Centro de Química Estrutural, Instituto Superior Técnico, Av. Rovisco Pais, 1049‐001 Lisboa, Portugal;3. 3B's Research Group—Biomaterials, Biodegradables, Biomimetics, Department of Polymer Engineering, University of Minho, Campus de Gualtar 4710‐053 Braga, Portugal;4. Department of Polymer Engineering, University of Minho, Campus de Azurém 4800‐058 Guimar?es, Portugal;5. REQUIMTE, Departamento de Química, Faculdade Ciências e Tecnologia, Universidade Nova de Lisboa, 2829‐516 Caparica, PortugalREQUIMTE, Departamento de Química, Faculdade Ciências e Tecnologia, Universidade Nova de Lisboa, 2829‐516 Caparica, Portugal |
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| Abstract: | Ethylene and 10‐undecen‐1‐ol copolymers, prepared using a nickel complex as catalyst, were studied using differential scanning calorimetry (DSC), X‐ray diffraction, and dielectric relaxation spectroscopy. The behavior exhibited by copolymers containing incorporated 10‐undecen‐1‐ol amounts within 0.5 and 4.6 mol % was compared with neat polyethylene. DSC revealed that a new crystalline region with lower thickness lamellae emerges in copolymers due to the side‐chains crystallization. Nevertheless, the global crystallization degree decreases due to the loss of crystallinity that occurs in a greater extent in PE‐like regions. Dielectric relaxation spectroscopy detected two processes, a low activation energy process below ?20 °C related with localized mobility increasing in intensity and deviating to higher temperatures with the increase in 10‐undecen‐1‐ol amount, and a high activation energy process ascribed to the glass transition, located at higher temperatures for the different copolymers relatively to neat polyethylene. © 2007 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 45: 2802–2812, 2007 |
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| Keywords: | copolymerization dielectric relaxation polyethylene |
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