title: Extruded blend films of poly(vinyl alcohol) and polyolefins: common and hard-elastic nanostructure evolution in the polyolefin during straining as monitored by SAXS.
abstract: Straining of PVA/PE and PVA/PP blends (70:30) is monitored by small-angle x-ray scattering (SAXS). Sheet-extruded films with different predraw ratio are investigated. The discrete SAXS of predrawn samples originates from polyolefin nanofibrils inside of polyolefin microfibrils immersed in a PVA matrix. PE nanofibrils deform less than the macroscopic strain without volume change. PP nanofibrils experience macroscopic strain. They lengthen but their diameter does not decrease. This is explained by strain-induced crystallization of PP from an amorphous depletion shell around the core of the nanofibril. The undrawn PVA/PE film exhibits isotropic semicrystalline nanostructure. Undrawn PVA/PP holds PP droplets containing oriented stacks of semicrystalline PP like neat precursors of hard-elastic thermoplasts. Respective predrawn films are softer than the undrawn material, indicating conversion into the hard-elastic state. Embedding of the polyolefin significantly retards neck formation. The polyolefin microfibrils can easily be extracted from the water-soluble matrix.
authors.affiliation: Department of Chemistry, University of Hamburg, Bundesstrasse. 45, D-20146 Hamburg, Germany.
authors.forename: Norbert
authors.initials: N
authors.lastname: Stribeck
authors.affiliation: Department of Chemistry, University of Hamburg, Bundesstrasse. 45, D-20146 Hamburg, Germany.
authors.forename: Ahmad
authors.initials: A
authors.lastname: Zeinolebadi
authors.affiliation: Mechanical Engineering Department, University of Auckland, Private Bag 92019, Auckland, New Zealand.
authors.forename: Stoyko
authors.initials: S
authors.lastname: Fakirov
authors.affiliation: Mechanical Engineering Department, University of Auckland, Private Bag 92019, Auckland, New Zealand.
authors.forename: Debes
authors.initials: D
authors.lastname: Bhattacharyya
authors.affiliation: HASYLAB at DESY, Notkestrasse. 85, D-22603 Hamburg, Germany.
authors.forename: Stephan
authors.initials: S
authors.lastname: Botta
keywords: 10.13; 20.05; 30.1; blend polymer film; hard-elastic; mechanical properties; microstructure; small-angle x-ray scattering; straining