Film formation from latex: Hindered initial interdiffusion of constrained polystyrene chains characterized by small-angle neutron scattering |
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Authors: | M. A. Linné A. Klein G. A. Miller L. H. Sperling G. D. Wignall |
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Affiliation: | 1. Polymer Science and Engineering Program Department of Chemical Engineering Materials Research Center #32 , Lehigh University , Bethlehem, Pennsylvania, 18015;2. Dow Chemical , Midland, Michigan, 48674;3. Director of NCSASR Oak Ridge National Laboratory , Oak Ridge, Tennessee, 37830 |
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Abstract: | Bulk polystyrene film samples were made from a 50% deuterated latex with a molecular weight of 5.85 × 106 g/mol and 38 nm particle diameter. Because of the high molecular weight and small particle size, these chains are constrained in dimensions by a factor of four. Mildly molded (compacted to full density) samples were annealed for increasing time periods and their small-angle neutron scattering (SANS) patterns recorded. The radii of gyration increase with time as segmental diffusion proceeds during film formation. The initial diffusion was hindered, as shown by a slower than expected relaxation of the chains. Residual interfacial effects were postulated to be the main cause. Chain interdiffusion between latexes of about 110 Å is sufficient to develop a tough, coherent film. |
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