Papers by Keyword: Phase Morphology

Abstract: Thermoplastic polyurethane (TPU)/polypropylene (PP) blends with different weight ratios were prepared in a novel vane extruder generating global and dynamic elongational flow. The results indicated that the addition of TPU elastomer to PP significantly improved the mechanical properties of the blends. From the SEM micrographs it could be clearly observed dispersed TPU deformed to be fibers by the effect of elongational flow. Meanwhile the results observed from DSC curves revealed apparent partial miscibility of the blends and enhanced crystallization ability of PP due to the influence of elongational flow

Abstract: In commercial 8xxx alloys several material characteristics such as softening behaviour, strength and technological ductility are influenced by alloying elements in their solute and precipitated form (i.e. microchemistry). Depending on the thermo-mechanical processing conditions a spectrum of microchemistry states (including variations of solute level, phase volume fraction, phase morphology) and therefore a spectrum of possible microchemistry-microstructure interactions can be obtained and used for a set up of sheet properties. In the present paper, the impact of homogenization conditions on the microchemistry development in selected 8xxx alloys is discussed with a view of controlling final properties. Effect of the processing route on the microchemistry evolution is demonstrated using the statistical Classical Nucleation and Growth (ClaNG) model.

Abstract: The phase morphology, rheology, and crystallization properties of the PA6/PP-g-MAH/POE blends prepared by melt-blending method were studied by scanning electron microscopy (SEM), capillary rheometer and differential scanning calorimetry (DSC), respectively. The results suggest that the compatibility of PA6 and POE can be improved by the compatibilizer of PP-g-MAH and the 10% of PP-g-MAH is preferred. PP-g-MAH and PA6 can both serve as nucleating agents for each other, and improve their crystallization behaviors. All melts of PA6/PP-g-MAH/POE blends are pseudo-plastic fluids, and PP-g-MAH components can increase the melt apparent viscosity due to its inherent higher viscosity, and so the processing property of the blend will be controlled in much wider temperature range.

Abstract: In this article, the phase morphology and mechanical properties of poly (trimethylene terephthalate)/maleinized poly (octene-ethylene) copolymer blends are studied by using scanning electron microscopy (SEM), polarized optical microscopy (POM), universal material tester and charpy impact tester. The results suggest that the crystal size of the blends decreases obviously and POE component is partly served as nucleating agent for the crystallization of PTT. PTT and POE have good compatibility in blends because the dispersed phase of POE has even dispersion in blends when POE content is lower than 5%; however, the dispersion state of POE becomes poor when POE content is larger than 5%. The impact strength increases to maximum when the POE content is about 4 %. The tensile strength gets to maximum when POE content is 1-2 %.

Abstract: The phase morphology and dynamic rheology of poly (trimethylene terephthalate)/maleinized poly (octene-ethylene)/organo-montmorillonite nanocomposites were investigated by using transmission electron microscopy (TEM) and rotational rheometer. The results suggest that some of the OMMT are peeled off and the nanosheets are dispersed evenly in the polymer matrix. When the OMMT content is more than 4%, they are tended to form the aggregates in nanocomposites. The nanocomposites’ melt are pseudo-plastic fluid, and both complex viscosity and shear storage modulus increase with increasing OMMT content due to the interaction between the OMMT and polymers. The nanocomposites’ melt show more elasticity behavior with more OMMT content especially at low shear frequencies.

Abstract: This paper presents a research concerning the equilibrium of ferrite and secondary cementite and Widmanstätten structure formation, resulting in precise conditions. If all researchers agree with the mechanisms of ferrite and massive cementite formation in steels, the Widmanstätten structure formation is rather disputable and new data in the area of massive transformation might account for the formation of Widmanstätten structures in the low carbon steels. For the massive phase and Widmanstätten structures, the mathematic relations regarding the rate of growth are presented.