Solvent-assisted NMR imaging or heterogeneous coal macromolecular networks
Solvent swelling has been employed to probe the physical structure of coal (1). The swelling behavior of bituminous coals in various solvents has been used to assess different strengths or types of secondary interactions which determine their macromolecular structures (2-5). The phenomenon of solvent transport into coal during solvent swelling has also been extensively investigated by numerous researchers (6-10). Recently, we have obtained important information concerning solvent accessibility in coals and maceral domains by proton NMR imaging of mobile proton distributions resulting from solvent swelling (11). Images of coals swollen with perdeuterated solvents were used to map mobile phases in the coal macromolecular structure, while images obtained with protic solvents mapped distributions of the ingressed solvent. For the present purposes 2-D images are sufficient and their acquisition is suitably fast. In order to ensure that the transport process was also two-dimensional, the upper and lower sample surfaces were protected from solvent infiltration by glass coverslips which restricted the flow of solvent to cross only the exposed faces of the sample. Each sample is rectangular with initial dimensions on the order of 2 {times} 2 {times} 1 mm. The experimental protocol involved immersing the sample in the solvent for a period of time, removing it from the solvent bath, acquiring an image, and re-immersing it. Figure 1 presents transient images together with one-dimensional projections for each of the three macromolecular systems.
- Research Organization:
- Argonne National Lab. (ANL), Argonne, IL (United States)
- Sponsoring Organization:
- USDOE, Washington, DC (United States)
- DOE Contract Number:
- W-31109-ENG-38
- OSTI ID:
- 10180781
- Report Number(s):
- ANL/CHM/CP-78384; CONF-930904-7; ON: DE93019771
- Resource Relation:
- Conference: 7. international conference on coal science,Banff (Canada),12-17 Sep 1993; Other Information: PBD: [1993]
- Country of Publication:
- United States
- Language:
- English
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