Modified method for obtaining the critical cooling rate for vitrification of polymers

Abstract

Due to the relevance of the critical cooling rate, Rc, for glasses, Barandiarán and Colmenero (BC) developed a method for calculating Rc as a function of the crystallization temperature on cooling obtained from thermal analysis. The critical cooling rate is obtained by the extrapolation method to conditions of infinity undercooling. However, for polymers, there is a strong reason for modifying the original BC method. In this case, the extrapolation must be extended only to the undercooling associated to the glass transition temperature, Tg, because no crystallization can occur below this temperature. Following this modified method (MBC) proposed by the present authors, the critical cooling rate for PP, PEEK, P10MS and PET were determined. The results showed that the new values are much lower than those obtained by the original BC method

Magnetic heating of nanoparticles as a scalable cryopreservation technology for human induced pluripotent stem cells

“…In the cryopreservation process, both cooling and warming rates should exceed the critical cooling rate (CCR) 17 and critical warming rate (CWR) 18 to avoid failure of vitrification, resulting in cell damage caused by ice crystal growth 19 . In large scale cryopreservation, one of the major technological barriers is achieving the CWR to avoid devitrification, because the conventional method of rewarming is performed by immersing vitrified cells in a water bath at 37 °C to avoid cellular damage caused by overheating.…”