Amino modified polydimethylsiloxane emulsions with excellent thermal stability and hydrophilicity for application in spinning oil of PAN precursors

Spinning oil was an important adjuvant used in the process of polyacrylonitrile (PAN) precursors. In this article, amino modified polydimethylsiloxane (AMPS) emulsions with excellent properties that could be used as spinning oil were successfully prepared. AMPS was synthesized firstly with octamethylcyclotetrasiloxane (D4), 3-(dimethoxy(methyl)silyl)propylamine (KH554) and decamethyltetrasiloxane(MD2M). The AMPS emulsion was prepared with AMPS, emulsifiers, acetic acid and water, and the influence of amino content on the properties of AMPS and AMPS emulsions was investigated in detail. The introduction of amino decreased the thermal decomposition temperature and enhanced the thermal stability of AMPS at 500–600 °C. In addition, the particle size and water contact angles of AMPS emulsion were obviously reduced with the increase of amino content, as the interaction between AMPS and PAN was enhanced. When the proportion of KH554 was 7.5%, AMPS emulsion had a proper particle size of 160.3 nm and a small contact angle of 34.5° with PAN film, which could be applied as spinning oil during the processing of PAN precursors. The optimum solid content of AMPS emulsion coating on the PAN precursors was also investigated. The surface of PAN precursors was smooth and the grooves were nearly repaired with the solid content of 1 wt%.