A non‐invasive NMR relaxometric characterization of the cyclododecane–solvent system inside porous substrates

Abstract

With the aim of deepening the knowledge on the behavior of cyclododecane (CDD) as a temporary consolidant agent for weathered stones, NMR longitudinal and transverse relaxation decays have been exploited to follow the distribution of cyclododecane solutions into porous matrices. By measuring as function of time the relaxation decay constants of CDD solutions dropped onto porous supports, it has been possible to differentiate the step encompassing the solvent evaporation, which determines the consolidant migration within the matrix, from that governing the consolidant sublimation, which is related to the consolidation effectiveness over time.

Cultural Heritage Studies with Mobile NMR

“…[24,62] Moreover,h ydrophobic substances are employed to reduce capillary water uptake while keeping the pore network intact so that the stone can still transport water vapor. [63] Fore xample,t he penetration depth and properties of stone conservation agents has been studied [64,65] by recording the moisture content as af unction of depth. [66][67][68][69][70] In this way,u nilateral NMR can help to identify the state prior to treatment and the efficiency of the treatment.…”

Unilaterale NMR zur Untersuchung von Kunst und Kulturgut

“…Weiterhin werden hydrophobe Beschichtungen eingesetzt, die die kapillare Wasseraufnahme reduzieren, aber das Porennetzwerk intakt halten, um den Transport von Wasserdampf nicht vollständig zu unterbinden . Die Eindringtiefe und Eigenschaften von Steinkonservierungsmitteln wurden charakteriesiert, indem der Wassergehalt als Funktion der Tiefe abgebildet wurde . Auf diese Weise kann unilaterale NMR helfen, den Zustand vor einer Behandlung sowie die Effektivität einer solchen zu bestimmen .…”

Cyclododecane shaping, sublimation rate and residue analysis for the extraction of painting micro-samples from resin cross-sections

“…CDD normally sublimes in approximately 24 h at room temperature 55 , 65 , but as was already mentioned, the application process, the layer thickness and the storage environment impact the sublimation time 55 , 64 , 66 . Thus, sublimation can be a matter of hours to weeks 67 .…”

“…It can be used pure and melted 59 , between 80 and 100 °C 60 or mixed with solvents 47 , 61 . Depending on the method and the temperature of application and cooling 62 , the recrystallisation is affected 63 and affects the CDD properties 47 , such as the penetration depth, film thickness 63 and sublimation rate 55 , 64 . Prescutti et al 59 determined that a highly concentrated CDD solution or pure melted CDD has a low infiltration power and recrystallises more quickly compared with a low-concentration solution in large crystals, creating a thick and compact layer on the surface of the sample.…”