Table 1 Summary of key findings for paint aged 11 months (cross section, DMA and Nanoindentation) and 21 months (SEM imaging)
From: A pilot study of solvent-based cleaning of yellow ochre oil paint: effect on mechanical properties
Investigation technique | Sample type | Age of paint film (months) | |
|---|---|---|---|
11 | 21 | ||
Cross section | Untreated sample | Untreated sample had a UV-fluorescent medium skin present at the paint surface; ca. 9–15 μm thick | N/A |
SEM | 24-h immersion | N/A | Surface disruption caused by deinoised water and shellsol D40. No visible changes caused by D5 |
Sponge cleaning | N/A | No visible changes to the surface for any of the selected solvents | |
DMA (bulk mechanical propertie) | 24-h immersion | Deionised water caused a fivefold increase in storage modulus (E') or stiffness; Shellsol D40 caused a twofold increase in stiffness; there were no measurable changes to paint stiffness caused by D5 Also, differences in Tg were observed based on the tan δ measurements | N/A |
Sponge cleaning | No significant change of bulk mechanical properties E' or Tg was measured for any of the selected solvents | N/A | |
Nanoindentation (surface mechanical properties) | Untreated sample | There is considerable variation in measured reduced storage modulus (Er′) and loss tangent, (tan δ) across the surface at a given measurement depth, owing to the inherent variability of the surface The reduced storage modulus, (Er′) and loss tangent (tan δ) increase and decrease respectively with increasing depth. This is consistent with the surface having a lower PVC, and being less stiff and more medium rich compared to bulk paint | N/A |
24-h immersion | Reduced storage modulus (Er′) or stiffness increased fivefold following immersion in water | N/A | |
Sponge cleaning | No significant changes to surface mechanical properties i.e. reduced storage modulus (Er′) or loss tangent (tan δ) were detected following sponge cleaning with either of the three selected solvents | N/A | |