Influence of DMDBS on the morphology and mechanical properties of polypropylene cast films

TitleInfluence of DMDBS on the morphology and mechanical properties of polypropylene cast films
Publication TypeJournal Article
Year of Publication2011
AuthorsSreenivas, K, Pol, HV, Kumaraswamy, G
JournalPolymer Engineering and Science
Volume51
Issue10
Pagination2013-2023
Date PublishedOCT
ISSN0032-3888
Abstract

We investigate extrusion film casting (EFC) of polypropylene (PP) and examine the effects of varying the concentration of nucleating agent, dimethyl dibenzylidene sorbitol (DMDBS); melt temperature at the die exit; and the draw ratio. Addition of DMDBS increases the PP crystallization temperature, and consequently the PP lamellar repeat spacing. For the draw ratios explored, we do not observe any substantial orientation of iPP crystals for films of neat iPP. However, addition of DMDBS results in the formation of oriented PP crystals, with greater orientation for higher draw ratios. On cooling from the melt, a network of DMDBS nanofibers forms in the PP. We believe that flow-alignment of this DMDBS network templates the orientation of PP crystals. We observe that the tensile modulus and yield stress increase with PP crystal orientation. However, at high DMDBS concentrations (0.8%), films have poor mechanical strength due to formation of voids and defects. POLYM. ENG. SCI., 51:2013-2023, 2011. (C) 2011 Society of Plastics Engineers

DOI10.1002/pen.21957
Type of Journal (Indian or Foreign)Foreign
Impact Factor (IF)1.302
Divison category: 
Polymer Science & Engineering