01724nas a2200169 4500008004100000022001400041245009500055210006900150260006700219300001400286490000700300520105700307100001801364700002701382700002701409856011801436 2011 eng d a0032-388800aInfluence of DMDBS on the morphology and mechanical properties of polypropylene cast films0 aInfluence of DMDBS on the morphology and mechanical properties o a111 RIVER ST, HOBOKEN 07030-5774, NJ USAbWILEY-BLACKWELLcOCT a2013-20230 v513 a
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
1 aSreenivas, K.1 aPol, Harshawardhan, V.1 aKumaraswamy, Guruswamy uhttp://library.ncl.res.in/content/influence-dmdbs-morphology-and-mechanical-properties-polypropylene-cast-films-0