Przemysl Chemiczny, Vol.84, No.2, 101-104, 2005
X-Ray diffraction studies on the degree of crystallinity of recycled poly(ethylene terephthalate) involving the Marquart-Levenberg method of analysis
Post-consumer bottle PET was washed, dried and flaked, 10x15-mm, 0.3 g/cc, fed into a double-screw extruder (160 rpm, 225 kg/hour) and cut at 40 degrees C in a water bath into 3x3-mm granules, 0.76 g/cc. These were x-rayed and the lines less than 4 degrees in half-width were taken as evidence for the amorphous phase. The regranulated PET was less crystalline, 8.83-13.30%, than virgin PET, 35%. The intrinsic viscosity and M followed the descending order. virgin PET granulate -> flakes -> regranulate, on account of progressing polymer degradation. A random PET collection scheme resulted in dispersed viscosity and crystallinity data. Solid state repolymn. would raise the viscosity of the regranulate to the virgin-grade level.