The synthesis and structural characterization of aramid-polydimethylsiloxane block copolymers

The block copolymers of the [(A)(x)(B)(y)](n) type, [(aramid)(x)( polydimet hylsiloxane)(y)](n) were synthesized by polycondensation of aramid and line ar amino propyl terminated polydimethylsiloxane oligomers. These block copo lymers have been characterized by infrared (IR), and nuclear magnetic reson ance (NMR) spectroscopy. The elemental analysis carried out was in agreemen t with calculated values. The molecular weight distribution (MWD) was inves tigated by gel permeation chromatography (GPC), the x and y values for all the copolymers were evaluated. Glass transition temperatures were determine d from differential scanning calorimetry (DSC) measurements. Each phase sho wed its normal or near normal, glass transition temperature for all the blo ck copolymers. The surface morphology studied by scanning electron microsco py (SEM), showed that the lamellar type of structure was dominant in all ar amid-polydimethylsiloxane block copolymers.