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Low‐temperature bitumen stiffness and viscous paraffinic nano‐ and micro‐domains by cryogenic AFM and PDM
Author(s) -
MASSON JF.,
LEBLOND V.,
MARGESON J.,
BUNDALOPERC S.
Publication year - 2007
Publication title -
journal of microscopy
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.569
H-Index - 111
eISSN - 1365-2818
pISSN - 0022-2720
DOI - 10.1111/j.1365-2818.2007.01796.x
Subject(s) - atomic force microscopy , microscopy , asphalt , asphaltene , phase (matter) , polar , phase transition , chemistry , optical microscope , chemical physics , chemical engineering , materials science , analytical chemistry (journal) , nanotechnology , composite material , thermodynamics , optics , organic chemistry , scanning electron microscope , physics , engineering , astronomy
Summary In an effort to better understand the structure and behaviour of bitumen in low temperature, we describe the first use of cryogenic atomic force microscopy and phase detection microscopy to characterize bitumen nano‐ and micro‐structures. The results were interpreted in light of glass transition temperatures ( T g s) for bitumen fractions. The domains visible by microscopy, the catana, peri and para phases, were attributed to domains rich in asphaltenes, naphthene and polar aromatics, and saturates, respectively. Between −10°C and −30°C, atomic force microscopy images revealed topographic features not visible in atomic force microscopy images acquired at room temperature. According to phase detection microscopy and T g s, the features were assigned to viscous unfrozen saturates. Upon cooling to −72°C, unfrozen domains of 20–400 nm were observed. These domains were found in the paraphase rich in saturates and in the periphase rich in naphthene aromatics and polar aromatics. The findings indicate that new viscous domains form upon cooling to low temperatures owing to phase segregation, and that some bitumens are never entirely rigid in low temperatures.