376 JOURNAL OF THE SOCIETY OF COSMETIC CHEMISTS C:OSO LLIB, I L I Z ERE F F I C I EHCV C.•stor Oil / Idiner.•l Oil - 50/513 61-] , • C,4 s TOIl \ [3..•,.... I•Ib/EI?AL OIL ..,& OIL' "' '•,,t.. E] REGRE::" S•,OIi LIHE i ' I " ..... ---' I ""J-•S[]:EM"S ' - I I I I o 'iEI SO LI_IB, I L IT'.? PARAhlET ER cd:' -"- ½'- -• ' I_:J._,l_l LLIB. I L I ..-ER Figure 3. Cosol•biIizcrs oeor c•stor oil/•incr•l oil. HAHT CONCLUSION Additives that induce miscibility between two otherwise immiscibile materials known as "coupling agents" may be incorrectly named. This term specifically appears to be a misnomer when applied to the castor oil/mineral oil system. Our analysis of the cohesive energies of 24 additives and the general behavior of 10 others shows that they act on the most polar (castor oil) component, thereby inducing miscibility with the mineral oil. The relationship of the cosolubilizer effectiveness to polarity indicates that nonelectro- lyte cosolubilizers do not induce "coupling" in the physical sense, as has previously been thought. The cosolubility between immiscible materials is instead effected through increased entropy within the most polar and cohesively energetic phase. The only coupling observed takes place between the cosolubilizer and the most polar ingredient in a process we have termed "cohesive blocking." The cosolubilizer serves to block or reduce the cohesive self-attraction of the polar castor oil, reducing the squeeze out (49) of the mineral oil. This mechanism provides an explanation for the effectiveness of isostearyl alcohol or oleyl alcohol in reducing syneresis (50) in wax/oil based products such as lipstick, cream rouge, car wax, and suppository formulations. But, more important, the implications of this mechanism should redirect cosolubilizer choices in formulation toward materials most closely matched to the most polar ingredient. ACKNOWLEDGMENT Sincere appreciation is extended to Dinesh Patel for his work and advice in investigating the range of solubilities above 9.0 (cal/cc) v2.

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