Small-angle neutron scattering composition

The morphological determinations have been performed by the small angle neutron scattering. It has been found that the structures mainly depend on the overall composition of the sample (the geometrical constraints). They may or may not exist, according to the temperature, but we always get lamellas for lowest water contents which turn into water-in oil globules. 

In this section we address the question of accordance between coexistence conditions determined for polymer mixtures in the bulk and confined in thin bilayer films. Macroscopic samples with the size of ca. 1 mm are analyzed by Small Angle Neutron Scattering. It probes the compositional fluctuations away from binodal to yield the effective interaction parameter %SANs(bilayer films are studied by profiling techniques to yield concentrations < q and 2 at binodal. These are described by the composition dependent interaction parameter %(([>). In fact only the section of the relation %(([>) bounded by ( q and <(>2 is relevant as it describes the whole intrinsic profile of Fig. 2. 

Many LLDPE are compositionally heterogeneous, since they contain molecules with few branches and molecules that are highly branched. The more highly branched fraction can be separated by solvent extraction. Small-angle neutron scattering (SANS) has confirmed the prediction that stmcturally disperse LLDPE display liquid-liquid phase separation, even if the overall branch content is low. These LLDPE behave like polyethylene blends even though they are the result of a single polymerization. 

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