THERMAL-BEHAVIOR OF BLENDS BASED ON HIGH-MOLECULAR POLYOXYETHYLENE AND SALTS FROM SEAWATER AND SEA LYE

The purpose of this study was to increase the thermooxidative stabilit y and flow of high-molecular polyoxyethylene (HMPOE) by introducing re adily available, technologically convenient, and economical additives. Binary systems consisting of HMPOE with mean viscosity molar mass (M) over bar(upsilon) = 3,2.10(6) g.mol(-1) and inorganic salts from both the seawater and sea lye and, also, MgCl2 of concentration from 1 to 10 mass % with respect to HMPOE, were prepared. The thermal behavior o f these systems was studied by using dynamic thermal analysis, dynamic viscometry, and melt index determination. The presence of salts of co ncentrations from 3 up to 10 mass % in HMPOE was found to increase the temperatures of initial thermooxidative decomposition of the polymer. At the same time, the degree of viscosity reduction (-Delta eta, %) c orresponding to lowering the average molar mass after the heat treatme nt for 20 h at 150 degrees C decreased. Another effect of the salts wa s found to be the increased melt flow of HMPOE above 250 degrees C. Th e best stabilizing effect was obtained in the presence of salts in sea lye and, also, MgCl2. (C) 1998 John Wiley & Sons, Inc.