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Ultra-High Resolution Small-Angle Neutron Scattering Investigations of Liquid-Liquid Phase Separation in Linear Low-Density Polyethylene

Published online by Cambridge University Press:  10 February 2011

M. M. Agamalian ,
R. G. Alamo ,
J. D. Londono ,
L. Mandelkern ,
S. Spooner ,
F. C. Stehling  and
G. D. Wignall
M. M. Agamalian
Affiliation:
Oak Ridge National Laboratory, Oak Ridge, TN 37831–6393
R. G. Alamo
Affiliation:
Florida Agricultural and Mechanical University and Florida State University College of Engineering, Department of Chemical Engineering, Tallahassee, FL 32310–6046
J. D. Londono
Affiliation:
Oak Ridge National Laboratory, Oak Ridge, TN 37831–6393
L. Mandelkern
Affiliation:
Institute of Molecular Biophysics, Florida State University, Tallahassee, FL 32306–3015
S. Spooner
Affiliation:
Oak Ridge National Laboratory, Oak Ridge, TN 37831–6393
F. C. Stehling
Affiliation:
Plastics Technology Division, Exxon Chemical Company, Baytown, TX 77520 (current address: 214 Post Oak, Baytown, TX 77520).
G. D. Wignall
Affiliation:
Oak Ridge National Laboratory, Oak Ridge, TN 37831–6393
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Abstract

Previous small-angle neutron scattering (SANS) studies [1] of heterogeneous ethylene-hexene linear low-density polyethylene (LLDPE) copolymers have confirmed the existence of a dispersed minority phase (volume fraction φ ∼ 10−2) consisting of highly branched, amorphous material. However, these experiments were conducted via a pinhole SANS spectrometer with an upper resolution limit ∼ 103 Å, whereas microscopy indicates that the dimensions of the disperse phase extend to the μm-range. We have therefore complemented these investigations via a Bonse-Hart ultra-small angle neutron scattering (USANS) instrument which increases the instrumental resolution in reciprocal space by a factor - 100, and thus particle size up to 30 μm can be resolved. The sensitivity of the USANS camera has recently been increased by two orders of magnitude by using the modified channel cut crystals [2], and the performance is therefore comparable to the best x-ray Bonse-Hart cameras. Xylene extraction removes the highly branched molecules and hence the volume fraction of the disperse phase is higher (φ ∼ 0.3) in the extracted material.

Type
Research Article
Information
MRS Online Proceedings Library (OPL) , Volume 461: Symposia BB – Morphological Control in Multiphase Polymer Mix… , 1996 , 205
Copyright
Copyright © Materials Research Society 1997

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References

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