Effect of composition on the gelation of tissue conditioners.

Tissue conditioners comprise poly(ethyl methacrylate) powder (or related copolymer) and a liquid containing a plasticizer and ethanol. Gelation times for two butyl/ethyl copolymers and one poly(ethyl methacrylate) polymer with buty phthalyl butyl glycollate or di-2-ethyl hexyl maleate and varying amounts of ethanol have been measured in the range 20-40 degrees C. The proprietary material "Viscogel" was used as a standard. Results were plotted according to the Arrhenius equation enabling activation energies to be determined. Values for activation energies ranged from 55 to 110 KJ mol-1 K-1. The 60/40 butyl/ethyl methacrylate copolymer gave the lowest values and those containing poly(ethyl methacrylate) the highest.