J. Duvall et al., EFFECT OF COMPATIBILIZATION ON THE PROPERTIES OF POLYAMIDE-66 POLYPROPYLENE (75 25 WT/WT) BLENDS/, Polymer, 35(18), 1994, pp. 3948-3957
Blends consisting of a polyamide 66 (PA) matrix (75 wt%) and a dispers
ed isotactic polypropylene (PP) phase were prepared by extrusion with
anhydride-grafted isotactic polypropylene compatibilizers, one of high
anhydride content (HAC, 2.7 wt% grafted maleic anhydride) and one of
low anhydride content (LAC, 0.2 wt% grafted anhydride). HAC and LAC ha
d similar effects on PP domain size and tensile properties at equal lo
adings, unlike the anhydride concentration dependency that had been re
ported for high PP content blends. As compatibilizer loading increased
from 0 wt% to 7.5 wt%, a skin/core injection-moulded morphology gradi
ent diminished, PP domain size decreased to less than 1 mu m, tensile
strain increased and microscale deformation of the PP phase progressed
from debonding to particle drawing and debonding to fibril fracture.
The PP phase deformation mode depends on the interfacial strength as c
ompared to the PP domain strength. HAC and LAC are postulated to behav
e similarly because of sufficient reactivity with PA and similar surfa
ce coverage by HAC-g-PA and LAC-g-PA. Interfacial strength is postulat
ed to increase with decreasing particle size because of increasing sur
face/volume ratio at relatively constant surface coverage.