Morphology and rheology of poly(trimethylene terephthalate)/metallocene linear low-density polyethylene (PTT/m-LLDPE) immiscible blends with varying extent of compatibilization were experimentally examined and theoretically analyzed using Palierne and Coran models. A glycidyl methacrylate-based terpolymer was used to modify the interface of the blend. The particle radius in the PTT75/m-LLDPE25 system decreases in proportion to the level of added compatibilizer up to 5 wt% of terpolymer, beyond which the particle size remains unchanged. This is attributed to the saturation of interface by interfacial modifier leading to diminish the effectiveness of the compatibilizer. Morphological observations reveal that the saturation of the interface for PTT25/m-LLDPE75 system occurs at 2.5 wt% compatibilizer content. Rheological examinations show a sharp reduction of complex viscosity for the latter system at 10 wt% terpolymer which is ascribed to the micelle formation in the bulk phase. Plots of the relaxation time spectrum exhibit that upon addition of the compatibilizer the magnitude of the relaxation peaks associated with interface increases which is ascribed to the increase of the interfacial area. The Palierne model fails to predict admissible values and reasonable trend for interfacial tension. This failure is believed to be due to the excessively large difference between the complex shear modulus values of the dispersed and matrix phases. However, the Coran model used to describe the dynamic moduli, shows a good fit to the experimental data. 相似文献
Summary: Blends of poly(trimethylene terephthalate) (PTT) and polycarbonate (PC) over full composition range were prepared using a twin‐screw extruder. A glycidyl methacrylate‐based terpolymer was used to modify the interface of the blends. Morphological examinations were carried out using transmission electron microscopy (TEM) and confirmed the biphasic structure of the blends. Dynamic rheological response of the blends was recorded in the linear viscoelastic region. It was observed that addition of the terpolymer to the system increases the dynamic shear moduli and complex viscosity of the blends, which is attributed to interactions of the terpolymer at the interface of two phases leading to a restricted chain mobility of the blend components. The Veenstra model was found to be able to describe dynamic shear modulus of the PTT/PC 50/50 blend; however, for the compatibilized blend of PTT/PC 50/50, the fit is not as good as that of uncompatibilized system, which is believed to be due to formation of micelles in this system.
Dynamic storage modulus of the compatibilized and uncompatibilized PTT/PC blends. 相似文献
The rheological, phase morphologic, thermal and mechanical properties of poly (trimethylene terephthalate)/metallocene polyethylene
(PTT/mPE) blends in the presence of ethylene propylene diene monomer copolymer grafted with maleic anhydride (EPDM-g-MAH) as compatibilizer are studied by means of a capillary rheometer, scanning electron microscopy (SEM), differential scanning
calorimetry (DSC) and thermogravimetric analyzer (TGA). Results suggest that the compatibility of PTT/mPE blends is improved
greatly after the addition of a compatibilizer. The radius of the dispersed phase in the system decreases greatly when the
compatibilizer is added into the blend. When the amount of compatibilizer exceeds 8 wt-%, the size of dispersed phase becomes
larger again. This phenomena could be attributed to the higher viscosity of the EPDM-g-MAH phase, which is dispersed more difficulty in the PTT phase of lower viscosity, thus the mixing efficiency is apparently
decreased during the melt blending process. Moreover, the melt viscosity of the blend reaches the maximal value in case of
4 wt-% compatibilizer content, above which it would decrease again. This result is associated with the generation of more
and bigger dispersed phase inside the bulk phase, thus the grafting efficiency at the interface is decreased, which could
result in lower viscosity. The DSC results suggest that the mPE component shows a nucleating effect, and could increase the
overall degree and rate of PTT crystallization, while the addition of a compatibilizer might slightly diminish these effects.
In addition, the blend with 4 wt-% compatibilizer shows the best thermal stability. Furthermore, the Izod impact strength
and the tensile strength at room temperature of the blend are also markedly improved by the addition of a 4–8 wt-% compatibilizer. 相似文献
The rheological, phase morphologic, thermal and mechanical properties of poly(trimethylene terephthalate)/metallocene polyethylene (PTT/mPE) blends in the presence of ethylene propylene diene monomer copolymer grafted with maleic anhydride (EPDM-g-MAH) as compatibilizer are studied by means of a capillary rheometer, scanning electron microscopy (SEM), differential scanning calorimetry (DSC) and thermogravimetric analyzer (TGA). Results suggest that the compatibility of PTT/mPE blends is improved greatly after the addition of a compatibilizer. The radius of the dispersed phase in the system decreases greatly when the compatibilizer is added into the blend. When the amount of compatibilizer exceeds 8 wt-%, the size of dispersed phase becomes larger again. This phenomena could be attributed to the higher viscosity of the EPDM-g-MAH phase, which is dispersed more difficulty in the PTT phase of lower viscosity, thus the mixing efficiency is apparently decreased during the melt blending process. Moreover, the melt viscosity of the blend reaches the maximal value in case of 4 wt-% compatibilizer content, above which it would decrease again. This result is associated with the generation of more and bigger dispersed phase inside the bulk phase, thus the grafting efficiency at the interface is decreased, which could result in lower viscosity. The DSC results suggest that the mPE component shows a nucleating effect, and could increase the overall degree and rate of PTT crystallization, while the addition of a compatibilizer might slightly diminish these effects. In addition, the blend with 4 wt-% compatibilizer shows the best thermal stability. Furthermore, the Izod impact strength and the tensile strength at room temperature of the blend are also markedly improved by the addition of a 4 8 wt-% compatibilizer. 相似文献
The physical properties of nylon 6/poly(acrylonitrile-butadiene-styrene) terpolymer (ABS) blends using a maleated polybutadiene
(denoted PB-g-MA) as compatibilizer were investigated. The morphology results reveal that ABS domain sizes decrease with an
increasing compatibilizer content, suggesting the good interaction between the nylon 6 matrix and the ABS dispersed phase.
Cooling conditions and compatibilizer contents strongly affect the crystalline structure of nylon 6, as determined from X-ray
diffraction and non-isothermal crystallization thermal analyses. The coexistence of α- and predominantly γ-form crystals for
the 10 phr compatibilized blends was observed. Isothermal crystallization kinetics suggests that the introduced compatibilizer
impeded the growth rate of the crystals, especially for the higher compatibilizer content. The compatibilizer was beneficial
in enhancing the thermal stability of the blends. 相似文献
Poly(trimethylene terephthalate)/polybutadiene grafted polymetyl methacrylate (PB-g-PMMA, MB) blends were prepared by melt processing with varying weight ratios (0-5 wt%) of diglycidyl ether of bisphenol-A (DGEBA) epoxy resin as a reactive compatibilizer. DMA result showed PTT was partially miscible with MB particles in the presence of the compatibilizer. Fourier transform infrared (FTIR) and rheological measurements further identified the reactions between PTT and DGEBA epoxy resin. Scanning electron microscopy (SEM) displayed that the core-shell structured modifiers exhibit a smaller dispersed domain size with the addition of DGEBA epoxy resin. Mechanical tests showed the impact and tensile properties of PTT blends are improved by the introduction of DGEBA epoxy resin to the blends. SEM and TEM results showed shear yielding of PTT matrix and cavitation of rubber particles were the major toughening mechanisms. 相似文献