Effects of temperature and relative humidity on fibrillar collagen in parchment: AÂ micro differential scanning calorimetry (micro DSC) study

Micro DSC measurements were used to investigate the synergistic effects of temperature and relative humidity on deterioration of parchment. Samples were obtained by exposing new parchments to various temperature and relative humidity atmospheres for increasing times in controlled test chambers. The impact of this accelerated ageing was assessed by measuring the thermodynamic parameters associated with the thermal denaturation of fibrillar collagen: variation of denaturation temperature, Tmax, indicated changes in collagen thermal stability, increases of DSC peak half-width, ΔT1/2, revealed greater thermal heterogeneity and structural disorder, whereas parallel decrease of denaturation enthalpy, ΔH, and DSC peak maximum height, Cpex max, measured the loss of fibrillar structure. Deconvolution of DSC denaturation peaks provided a valuable illustration of both the dynamics and the pattern of the deterioration of fibrillar collagen. Impact of temperature and relative humidity on parchment integrity and stability is discussed in terms of their implications for conservation science.