Initial flow of tissue conditioners--influence of composition and structure on gelation.

The effects of the molecular weight of polymer powders, the ethyl alcohol content of the liquids, the type of plasticizer and the polymer powder/liquid ratio on viscoelastic properties during gelation of tissue conditioners were studied with an oscillating rheometer. The results showed that: (i) The gelation time decreased exponentially with increases in molecular weight of the polymer powder and with powder/liquid ratio. There were linear relationships between the log of gelation time, and both the molecular weight of the polymer powder and the powder/liquid ratio. (ii) In general, gelation time decreased exponentially with increases in ethyl alcohol content. However, the relationship between the log of the gelation time and ethyl alcohol content fitted a second-order polynomial. (iii) The type of plasticizer affected gelation time. The order of gelation times was: benzyl benzoate < dibutyl phthalate < butyl phthalyl butyl glycolate. The initial flow of tissue conditioners could be controlled over a wide range by varying the molecular weight of the polymer powders, the ethyl alcohol content, the powder/liquid ratio and the type of plasticizer.