Summary: Polyacrylonitrile (PAN) particles with micro‐size ranges (0.15–2 μm) were prepared by emulsion and dispersion polymerizationa and in supercritical carbon dioxide media. The PAN particles were blended with Nylon 6 (PA6) at 220 °C by using a miniature mixer; it was found that melt‐mixing was possible for PAN‐rich compositions as high as 70 wt.‐%. Blends were characterized by scanning electron microscopy, IR, viscosity measurements, differential scanning calorimetry, and dynamic mechanical thermal analysis (DMTA). The size and shape of original PAN particles were retained in PAN/PA6 blends. The useful range to blend PAN particles size was less than 1 μm in terms of shape retention of the PAN particles in blends. Blends with 40 wt.‐% PAN content were found to be melt‐processable. The elastic modulus was higher for PAN/PA6 blends than pure PA6.
SEM photograph of PAN‐SC/PA6 blend with a 40/60 weight ratio. 相似文献
A simple semi-empirical analysis method for predicting the group effect of pile group under dragload embedded in clay was
described assuming an effective influence area around various locations of pile group. Various pile and soil parameters such
as the array of pile group, spacing of the piles (S), embedment length to diameter ratio of piles (L/D) and the soil properties such as density (γ), angle of internal friction (φ) and pile-soil interface friction coefficient (μ) were considered in the analysis. Model test for dragload of pile group on viscosity soil layer under surface load consolidation
conditions was studied. The variations of dragload of pile, resistance of pile tip and the layered settlement of soil with
consolidation time were measured. In order to perform comparative analysis, single pile was tested in the same conditions.
The predicted group effect values of pile group under dragload were then compared with model test results carried out as a
part of the present investigation and also with the values reported in literatures. The predicted values were found to be
in good agreement with the measured values, validating the developed analysis method. The model test results show that negative
skin friction of pile shaft will reach 80%–90% of its maximum value, when pile-soil relative displacement reaches 2 mm.
Foundation item: Project(50679015) supported by the National Natural Science Foundation of China 相似文献