PET/PC blends: Effect of chain extender and impact strength modifier on their structure and properties |
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Authors: | S. S. Pesetskii B. Jurkowski O. V. Filimonov V. N. Koval V. V. Golubovich |
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Affiliation: | 1. Department of Technology of Polymeric Composite Materials and Particles, V.A. Belyi Metal‐Polymer Research Institute of National Academy of Sciences of Belarus, 32a Kirov Street, Gomel 246050, Republic of Belarus;2. Plastic and Rubber Processing Division, Institute of Materials Technology, Poznan University of Technology, Piotrowo 3, 60‐950, Poznan, Poland;3. MFK Chemical Corporation, Works on processing of repeated resources, 29, Lazarenko St., Mogilev 212009, Republic of Belarus |
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Abstract: | Methylene diphenyl diisocyanate (MDI) affects the morphology, rheological, mechanical, and relaxation properties, as well as tendency to crystallize of PET in PET/PC/(PP/EPDM) ternary blends produced by the reactive extrusion. Irrespective of the blend phase structure, the introduction of MDI increases the melt viscosity (MFI dropped), resulting from an increase in the molecular weight of the polymer chains; the PET crystallinity was also reduced. MDI favors compatibility of PET with PC in PET/PC/(PP/EPDM) blends. This is explained by intensified interphase interactions on the level of segments of macromolecules as well as monomer units. The presence of MDI causes a substantial rise in the dynamic shear modulus within the high‐elastic region of PET (for temperature range between Tg,PET and that of PET cold crystallization); the processes of PET cold crystallization and melt crystallization become retarded; the glass‐transition temperatures for PET and PC become closer to each other. MDI affects insignificantly the blend morphology or the character of interactions between the disperse PP/EPDM blend and PET/PC as a matrix. PP/EPDM reduces the intensity of interphase interactions in a PET/PC/(PP/EPDM), but a rise in the degree of material heterogeneity. MDI does not change the mechanism of impact break‐down in the ternary blends mentioned above. Increased impact strength of MDI‐modified materials can be explained by higher cohesive strength and resistance to shear flow at impact loading. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011 |
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Keywords: | poly(ethylene terephthalate) polycarbonate chain extender impact strength modifier reactive extrusion compatibility interphase adhesion crystallization hydrolysis |
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