Journal of Applied Crystallography

Volume 40, Supplement (April 2007)

Hierarchy/wide-Q range

J. Appl. Cryst. (2007). 40 (Supplement), s97-s100

Hierarchical structures formed by partially crystalline polymers in solution: from fundamentals to applications - a combined conventional, focusing and ultra-small-angle neutron scattering study

A. Radulescu, D. Schwahn, J. Stellbrink, E. Kentzinger, L. J. Fetters and D. Richter

Abstract: Multilevel aggregates with characteristic sizes covering four orders of magnitude, from 1 nm to 10 µm, are formed upon cooling decane solutions of poly(ethylene-butene) random copolymers (designated as PEB-n, where n is the number of ethyl side branches per 100 backbone C atoms) and wax-containing mixed solutions. The partially crystalline PEB-7.5 copolymers form two distinct morphologies that evolve on a range of length scales. When these polymers are mixed with wax molecules having a crystallization point lower than the polymer aggregation temperature, a hierarchy of morphologies evolves on decreasing the temperature. The multilevel structures were elucidated by combining conventional small-angle neutron scattering, focusing small-angle neutron scattering and ultra-small-angle neutron scattering investigations with microscopy. Contrast-matching analysis of the wax and copolymer components within the common morphologies revealed the wax-crystal modification capacity of the PEB-7.5 copolymers. Since the copolymers limit the growth of wax crystals, they are potential pour-point depressants for the fuel industry.

Keywords: small-angle neutron scattering; focusing small-angle neutron scattering; ultra-small-angle neutron scattering; partially crystalline polymers.