Phase Behavior and Its Effects on Crystallization in a Poly(trimethylene terephthalate)/Phenoxy Resin Blend
Phase behavior and its effects on crystallization in an extruded poly(trimethylene terephthalate) (PTT)/phenoxy resin blend were studied with time-resolved light scattering (TRLS), optical microscopy (OM), differential scanning calorimetry (DSC), and small-angle X-ray scattering (SAXS). During annealing in the molten state, a two-phase structure with unique periodicity and phase connectivity was developed by liquid–liquid phase separation. After the formation of the phase-separated structure, the blend was homogenized by the interchange reactions between the two polymers. The crystallization behavior of PTT predominantly depended on the phase morphology developed during annealing. The pre-existing phase structures disturbed the lamellar orientation, resulting in a poorly ordered spherulitic superstructure.
Annealing effect on tensile property and hydrolytic degradation of biodegradable poly(lactic acid) reactive blend with poly(trimethylene terephthalate) by two-step blending procedure
Abstract A blending procedure utilizing a crystallized, tough, biodegradable poly(lactic acid) (PLA) blend with poly(trimethylene terephthalate) (PTT) and reactive compatibilizer, poly(ethylene-co-glycidyl methacrylate) (PEGMA), produced by two-step blending, was investigated in this research. The effects of the reactive compatibilizer and annealing temperature were investigated using an annealing PLA/PTT/PEGMA blend. The tensile properties of the annealed PLA/PTT/PEGMA blend were drastically improved compared with the annealed neat PLA and PLA/PTT blends. Craze formation was observed in the elongated area of the annealed PLA/PTT/PEGMA blend, and it was suggested to contribute to the toughening of the blend. The crystal's lack of spherulitic morphologies also contributed to the improved tensile properties, as confirmed by polarized optical microscopy (POM) and small-angle light scattering (SALS). The crystallization kinetics of the blends during annealing were also studied. Moreover, hydrolytic degradation of the blend could be controlled, after blending with PTT and PEGMA.
Evaluation of buckling load and dynamic performance of steel shear wall retrofitted with strips made of shape memory alloy
One of the most imperfections of the steel shear wall is out of plane displacements that cause severe damage in both structural and non-structural elements. In this paper, the effects of shape-memory alloys on steel shear walls are investigated. First, a numerical analysis using the finite element method in ABAQUS software has been carried out according to an experimental test. The results of the numerical analysis have been verified with experimental results. Next, shape-memory alloy fibers have been added vertically and horizontally to various parts of the steel shear wall. The results show that retrofitting with the shape-memory alloy reduces the out-of-plane displacement of the steel shear wall under both cyclic and seismic loadings. Besides, the buckling load in the steel shear wall increases when it is retrofitted with the shape-memory alloy. Also, the total out-of-plane movement (accumulated absolute displacements) of the steel shear wall and non-structural damage are controlled by the characteristic of a shape-memory alloy material called “super-elastic”.