caa a22 4500 46322423X CHVBK 20180405153222.0 cr unu---uuuuu 170326e20070501xx s 000 0 eng 10.1007/s10853-006-1434-4 doi (NATIONALLICENCE)springer-10.1007/s10853-006-1434-4 LLDPE's grown with Metallocene and Ziegler-Natta catalysts: events in the melt and FTIR analysis [Elektronische Daten] [Z. Ferhat-Hamida, H. Phuong-Nguyen, P. Bernazzani, A. Haine, G. Delmas] LLDPE samples synthesized with Ziegler-Natta (ZN) and Metallocene (MT) catalysts have been analyzed to investigate a potential catalyst-dependent morphology and to find an explanation for the difficult processing of MT. Slow calorimetry at v=0.02K/min and IR at RT and in the melt are used. The differences between MT and ZN are assigned to their different composition, MT not having the linear segments, which are present in ZN. Slow calorimetry is effectively a drawing process of the melt with chain orientation followed by decay. The later event, characterized by an endotherm, ΔH network, occurs at higher temperatures for MT, the presence of a regular distribution of methyl groups slowing down the process. The rocking, gauche, bending and stretching regions of the IR spectra are analyzed. The nascent MT has more strained bands in the rocking region. The wagging region reveals the more homogeneous environment of MT through the maximum absorbance at 1,368cm−1. Decomposition of bands is made for the rocking and wagging regions. The orthorhombic crystallinity, αc (FTIR), measures the sum of long- and short-range orthorhombic order, the latter being obtained by αc (FTIR)-αc (X-rays). The values of αc (FTIR) for MT and ZN are very similar in conditions of equilibrium. The justifications for the molecular origin of ΔH network are presented: (i) the slow relaxation of long chains strained and oriented in the melt measured by other techniques, (ii) The correlation, for gels of a linear sample, made in different solvents, between the maximum drawability, λmax, and ΔH network in a slow T-ramp. The range is 80-270 for λmax and 40-120J/g for ΔH network. (iii) The comparison of two traces of the same sample, between 140°C and 270°C, show that comparable events in the melt appear in the integrated absorbance and in the slow calorimetry signal. Analysis on thin films of the little-studied CH2 stretching region reveals that their extinction coefficient, ε, and the shape of the bands are highly sensitive to the sample history, ε diminishing by a large factor in slowly crystallized samples. Events in the slow T-ramp, followed by a fast crystallization, on the other hand, leads to materials with standard characteristics. Slow calorimetry traces display more events (endothermic and exothermic) for MT than for ZN, a finding consistent with more flow irregularities during processing. Equilibrium conditions and better processing could be reached for MT by extending time in the melt or using higher temperatures. Springer Science+Business Media, LLC, 2007 Ferhat-Hamida Z. Chemistry Department, Université du Québec in Montréal, CP 8888, Succ Centre ville, H3C 3P8, Montreal, Canada aut Phuong-Nguyen H. Chemistry Department, Université du Québec in Montréal, CP 8888, Succ Centre ville, H3C 3P8, Montreal, Canada aut Bernazzani P. Chemical Engineering Department, Texas Tech University, 79409-3121, Lubbock, TX, USA aut Haine A. Chemistry Department, Université du Québec in Montréal, CP 8888, Succ Centre ville, H3C 3P8, Montreal, Canada aut Delmas G. Chemistry Department, Université du Québec in Montréal, CP 8888, Succ Centre ville, H3C 3P8, Montreal, Canada aut Journal of Materials Science Kluwer Academic Publishers-Plenum Publishers; http://www.springer-ny.com 42/9(2007-05-01), 3138-3154 0022-2461 42:9<3138 2007 42 10853 https://doi.org/10.1007/s10853-006-1434-4 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/s10853-006-1434-4 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Ferhat-Hamida Z. Chemistry Department, Université du Québec in Montréal, CP 8888, Succ Centre ville, H3C 3P8, Montreal, Canada aut NATIONALLICENCE 700 1- Phuong-Nguyen H. Chemistry Department, Université du Québec in Montréal, CP 8888, Succ Centre ville, H3C 3P8, Montreal, Canada aut NATIONALLICENCE 700 1- Bernazzani P. Chemical Engineering Department, Texas Tech University, 79409-3121, Lubbock, TX, USA aut NATIONALLICENCE 700 1- Haine A. Chemistry Department, Université du Québec in Montréal, CP 8888, Succ Centre ville, H3C 3P8, Montreal, Canada aut NATIONALLICENCE 700 1- Delmas G. Chemistry Department, Université du Québec in Montréal, CP 8888, Succ Centre ville, H3C 3P8, Montreal, Canada aut NATIONALLICENCE 773 0- Journal of Materials Science Kluwer Academic Publishers-Plenum Publishers; http://www.springer-ny.com 42/9(2007-05-01), 3138-3154 0022-2461 42:9<3138 2007 42 10853 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer