Components of co-continuous phase can form an interpenetrating network structure, which has great potential to synergistically improve the mechanical properties of the blends, and to impart the functional blends superior electrical conductivity and permeability. In this work, the effects of shear rates (50–5000 s?1) at different temperatures on the phase morphology, phase size and lamellar crystallites of biodegradable co-continuous polybutylene terephthalate (PBAT)/polybutylene succinate (PBS) blend are quantitatively investigated. The results show that the above features of the PBAT/PBS have a strong dependence on the shear flow and thermal field. The co-continuous phase of the blend is well maintained at 130 °C. Interestingly, this phase structure transforms into a “sea-island” structure at 160 °C, which gradually recovers to a co-continuous phase when the shear rate increases from 1000 s?1 to 5000 s?1. The phase size decreases with the increase of shear rate both at 130 °C and 160 °C due to the refinement and deformation of phase structures caused by strong shear stress. Unexpectedly, a unique phenomenon is observed that the shear-induced lamellar crystallites are oriented perpendicular to shear direction in the range of 500–5000 s?1 at 130 °C, while the orientation of lamellar crystallites at 160 °C is along the shear direction within the whole range of shear rates. The degree of orientation for the PBAT/PBS blend crystals increases first and then decreases at both temperatures above. In addition, the range of shear rate has reached the level in the industrial processing. Therefore, this work has important guiding significance for the regulation of the co-continuous phase structure and the performance for the blend in the practical processing.
In this paper, 3-dimensional non-axisymmetrical deformation analyses for finite hollow circular cylinders have been carried
out by Pickett's double series expansion method[1]. Through expanding the displacement potentials as the sum of fourier series and Fourier-Bessel series, we could express the
coefficients of one series by those of another under certain boundary conditions. Thus, a set of linear algebraic equations
were derived. Solving these equations, we could obtain the solutions of the problems. Numerical examples have been given to
show that the method presented here is workable for practical applications. 相似文献
The fracture process of reinforced composite materials is examined. In the outer region of the crack tip anisotropic continuum mechanics is employed, while for the crack tip region a heterogeneous micromechanical model is proposed. A solution is obtained using combined boundary layer — non-linear finite elements. 相似文献
To date, most collision cross section (CCS) predictions have invoked gas molecule impingement-reemission rules in which specular and elastic scattering of spherical gas molecules from rigid polyatomic surfaces are assumed. Although such predictions have been shown to agree well with CCSs measured in helium bath gas, a number of studies reveal that these predictions do not agree with CCSs for ions in diatomic gases, namely, air and molecular nitrogen. To further examine the validity of specular-elastic versus diffuse-inelastic scattering models, we measured the CCSs of positively charged metal iodide cluster ions of the form [MI]n[M+]z, where M?=?Na, K, Rb, or Cs, n?=?1 – 25, and z?=?1 – 2. Measurements were made in air via differential mobility analysis mass spectrometry (DMA-MS). The CCSs measured are compared with specular-elastic as well as diffuse-inelastic scattering model predictions with candidate ion structures determined from density functional theory. It is found that predictions from diffuse-inelastic collision models agree well (within 5 %) with measurements from sodium iodide cluster ions, while specular-elastic collision model predictions are in better agreement with cesium iodide cluster ion measurements. The agreement with diffuse-inelastic and specular-elastic predictions decreases and increases, respectively, with increasing cation mass. However, even when diffuse-inelastic cluster ion predictions disagree with measurements, the disagreement is of a near-constant factor for all ions, indicating that a simple linear rescaling collapses predictions to measurements. Conversely, rescaling cannot be used to collapse specular-elastic predictions to measurements; hence, although the precise impingement reemission rules remain ambiguous, they are not specular-elastic.
