MICROSTRUCTURAL CHARACTERIZATION OF PA-6 PP BLENDS FORMED DURING REACTIVE EXTRUSION OF EPSILON-CAPROLACTAM/

Consideration is given to the determination of phase and crystalline m icrostructure existing in blends of polyamide 6 (PA-6) and polypropyle ne (PP) both made by melt mixing these polymers and by polymerising E- caprolactam inside a twin-screw extruder in the presence of PP homopol ymer. Using a variety of characterisation techniques, including DSC, W AXD, SEM, FTIR spectroscopy and DMTA, so-called reaction blends can be shown to exhibit greatly increased phase miscibility, relative to the melt blended counterparts, particularly at a 90/10 PA-6/PP weight rat io. This is attributed to the in situ formation of a PA-6-g-PP copolym er during blend preparation, which also inhibits crystallisation of th e PP phase.