The relaxation of additives in polymer matrix
The dielectric properties of synthetic polyisoprene (IR 305) samples with additives of acetonitrile were studied by means of the thermally stimulated depolarization current (TSDC) method. Acetonitrile in concentration from 0.02 to 5 wt% was added to synthetic polyisoprene samples IR 305. The dielectric measurements of natural rubber (NR) before and after extraction and measurements of IR 305 with extract from NR were studied by means of TSDC method and by means of temperature dependence of loss factor at fixed frequency. The measurements were carried out in the temperature range −150°C to +130°C
The high temperature absorption in NR and in IR 305 with extract was studied in detail and it can be seen that it is caused by orientational movement of additives in these materials.
The behavior of IR 305 with acetonitrile is more complicated. The main transition region is enlarged by the acetonitrile and we can observe its plasticizing effect in this region. The movement of free acetonitrile molecules in IR 305 appears at relatively high amounts of acetonitrile.
Key wordsDielectric relaxation depolarization current additives in polyisoprene
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