Wax crystallization from solution in hierarchical morphology templated by random poly(ethylene-co-butene) self-assemblies

摘要

Semicrystalline poly(ethylene-butene) (PEB-n) random copolymers can modify the sizes of wax crystals and thus improve the viscoelastic properties of crude oil and middle distillate fuels at low temperatures. The wax-copolymer interactions in solution are rather complex and not fully understood. When the copolymer self-assembles at temperatures higher than the wax cloud point a hierarchy of morphologies templated by the primordial polymer structure evolves with decreasing temperature. Multilevel structures showing characteristic sizes from 10 mu m to 1 nm are formed upon cooling in solutions of semicrystalline PEB-7.5 copolymers and in wax containing mixed solutions. The coplymer structures with the different wax molecules were evaluated by three SANS techniques (conventional SANS, focusing-SANS and ultra-SANS) and contrast matching. Complementary microscopy techniques allowed a direct visualization of these structures in real space.