MORPHOLOGICAL EVOLUTION AND VISCOELASTIC BEHAVIOR OF COMPATIBILIZED HDPE/PA6 BLENDS
HDPE/PA6反应增容体系的形态演化与黏弹行为

Morphologies and viscoelastic behavior of high density polyethylene/nylon 6(HDPE/PA6) blends compatibilized by maleic anhydride grafted high density polyethylene(HDPE-g-MAH) were studied through observation of scanning electron microscope(SEM) and dynamic rheological testing.It is found that HDPE-g-MAH can efficiently enhance the compatibility between PA6 and HDPE and improve the dispersion of PA6 and the interfacial state of phases due to in situ forming of graft copolymer(HDPE-g-PA6).Such improvement appears more obviously with the increasing of HDPE-g-MAH content when the concentration of HDPE-g-MAH is below 20 wt%.Hence,change of HDPE-g-PA6 amount also results in corresponding variations of linear viscoelastic behavior for the blends.The zero shear viscosity of blends increases with the addition of HDPE-g-MAH and approaches invariablenes with 20 wt% HDPE-g-MAH.At low frequency region the dependence of storage modulus on frequency for the blends tends to be weakened with the increase of HDPE-g-MAH concentration and begins to show "second plateau" with 10 wt% HDPE-g-MAH.These phenomena reflect macromolecular-chains entanglement enhancement due to HDPE-g-PA6 forming.Both changes in morphologies and viscoelastic behavior for blends are ascribed to formation of HDPE-g-PA6.Compared with SEM observation,dynamic rheological testing gives much information about interface and interaction between macromolecular-chains.It is suggested that structure evolution with increase of HDPE-g-MAH content for HDPE/PA6 blends can be characterized preferably by using dynamic rheological measurements.