Plasticization and cocrystallization in LLDPE/wax blends |
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| Authors: | Thandi P Gumede Adriaan S Luyt Ricardo A Pérez‐Camargo Amaia Iturrospe Arantxa Arbe Manuela Zubitur Agurtzane Mugica Alejandro J Müller |
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| Affiliation: | 1. Deparment of Chemistry, Faculty of Natural and Agricultural Sciences, University of the Free State (Qwaqwa Campus), Phuthadithjhaba, South Africa;2. Center for Advanced Materials, Qatar University, Doha, Qatar;3. POLYMAT and Polymer Science and Technology Department, Faculty of Chemistry, University of the Basque Country UPV/EHU, Donostia‐San Sebastián, Spain;4. Centro de Física de Materiales (CFM) (CSIC‐UPV/EHU)‐Materials Physics Center (MPC), Donostia‐San Sebastián, Spain;5. Chemical and Environmental Engineering Department, Polytechnic College, University of the Basque Country UPV/EHU, Donostia‐San Sebastián, Spain;6. IKERBASQUE, Basque Foundation for Science, Bilbao, Spain |
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| Abstract: | The structure and thermal properties of linear low‐density polyethylene (LLDPE)/medium soft paraffin wax blends, prepared by melt mixing, were investigated by differential scanning calorimetry (DSC) and small‐ and wide‐angle X‐ray scattering (SAXS and WAXS). The blends form a single phase in the melt as determined by SAXS. Upon cooling from the melt, two crystalline phases develop for blends with more than 10 wt % wax characterized by widely different melting points. The wax acts as an effective plasticizer for LLDPE, decreasing both its crystallization and melting temperature. The higher melting point crystalline phase is formed by less branched LLDPE fractions. On the other hand, the lower melting point crystalline phase is a wax‐rich phase constituted by cocrystals of extended chain wax and short linear sequences of highly branched LLDPE chains. The presence of cocrystals was evidenced by standard DSC results, successive self‐nucleation and annealing (SSA) thermal fractionation and by the detection of a new SAXS signal attributed to the lamellar long period of the cocrystals. © 2016 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2016 , 54, 1469–1482 |
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| Keywords: | cocrystallization LLDPE/wax blends plasticization SAXS SSA thermal fractionation |
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