| Isotactic polypropylene/ Poly(ethylene-1-octene) (PP/POE) blends with various blend ratios were prepared in an intermeshing co-rotating twin-screw extruder under different mixing conditions. The morphology development,thermal properties and rheology properties of PP/POE blends were investigated in details by Scanning Electron Microscopy (SEM), In-line Small Angle Laser Scattering (in-line SALS), Differential scanning calorimetry (DSC) and Rotational rheometer.The influences of blend composition and processing conditions (mixing time,rotor speed and mixing temperature) on phase morphology development of the blends were investigated by SEM. The experiment result showed the rule of phase morphology evolution of the blends, and the effect of viscoelastic rheological and thermodynamic properties on the rule are given.There are exist an critical particle size below which the phase colascene will be observed. Under the mixing conditions we chose, the critical particle size is 0.25μm. With the dipersed content incresing, the dispersed phase dimension is increased. The optimum mixing conditions is that 84rpm and 210-220℃.The solidification process of the blends in intrim mixer is investigated by SEM and in-line SALS. The result shows phase coalescence occurs in the normal cooling process and analysis the reason of it. The confinment crystallization behaviors of PP which the crystallization temperature is lowered than the bulk polymer was first obseverd during the solidification process. WAXD graph incidated that the crystallization structure is not chang. The syudy of shear induce phase coalescence of blends incidates that the morphology development should be composed of three parts. The three parts can be described by various scaling function.DSC was used to get the thermodynamic properties of PP/EOC blends. Melting, crystallization behaviors showed that the two components are partly miscible. When the POE dispersed as particles, melting curve and WAXD graph represents that the addition of POE do not affect the crystallizaiton structure of PP. The Avrami equation can be used to describe the isothermal crystallization of PP exactly. When the PP dispersed as particles in POE martix, the morphology of PP was obsevered by TEM in the solution directly. The corresponding DSC analysis indicates that the confinement crystallization is occur in the PP particles.The results of rheological measurement on PP/POE blends were list as follow. Temperature was a key factor in viscosity of the pure polymers and blends. The higher temperature the lower activation energy. It showed that viscosities of the blends were less sensitive to temperature. Under the condition of dynamic rheological measurements, viscosities and modulus decreased as temperature and addition of POE increased, except the blends with 10% and 20% POE. Under the condition of dynamic rheological measurement, the dynamic storage modulus, G', and the dynamic loss modulus, G"increased as the frequency increased. The complex viscosity,η*decreased as the frequency increased. The relation between modulus , viscosity and addition of POE showed that blends with 10% or 20% POE had the highest value. The blends with 10% POE had the longest relaxation time,τx at the temperature 220℃and 230℃. The results all above showed that interaction between molecular chain in blends with 10% or 20% POE were stronger than other blends. This may be related to the brittle-tough transition.
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