Role of aliphatic alcohols on the stability of rat-tail tendon (RTT) collagen fiber

The dimensional stability of collagen is related to hydrogen bonding, electrostatic, hydrophobic, London, or van der Waals forces, and weak: interactions. To assess the influence of dielectric constant of solvents on the ion pair interactions, in this work, influence of different aliphatic alcohols viz., methanol, ethanol, and n-propanol on thermomechanical behavior of rat-tail tendon (RTT) collagen fiber has now been investigated. The results show that the shrinkage temperature of native RTT decreases in aqueous alcoholic mixtures with increasing mol proportions of alcohol up to the level of 10 mol %, and when the mol proportion of alcohol exceeds 10 mol %, shrinkage temperature increases, possibly due to a desolvational effect. Further, the thermal and mechanical stability of native RTT is lower in n-propanol medium. The stress relaxation behavior of RTT is explained in terms of a two-element model, involving two superposed exponentials, and the rate constants corresponding to two relaxation processes have been computed using a nonlinear least square fit of experimental data. The activation energy values E-0, and Ed corresponding to the two relaxation processes identified, have been computed and the differential scanning calorimetric studies have been made to assess the enthalpy changes associated with the heat denaturation processes. (C) 1999 John Wiley & Sons, Inc.