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The phase behavior of coil-comb copolymers A–(B m+1 C m ) (side chain number m = 1–5) is investigated by real-space self-consistent field theory (SCFT). Depending on the copolymer composition and architecture, eight two-dimensional ordered phases are observed, including two-color lamellae (LAM 2 ), three-color lamellae (LAM 3 ), hexagonal cylinders (HEX), core–shell...
This paper describes the preparation and understanding of helical peanut-shaped ribbons of poly(vinyl pyrrolidone) (PVP) by a magnetic field-assisted electrospinning method. The relative humidity is found to significantly influence the morphology of PVP fibers. The morphology changed from straight rods to helical ribbons as relative humidity decreased. The percentage of helical ribbons increased dramatically...
Two donor–acceptor conjugated polymers PCTBTC8 and PCTTBTC12 have been prepared from Suzuki coupling reactions between the 2,7-carbazole and alkoxy substituted 2,1,3-benzothiadiazole units with two different linker groups thiophene and thieno[3,2-b] thiophene, respectively. The polymer PCTTBTC12 with the thieno thiophene linker group possessed a red-shifted UV-vis absorption spectrum and similar HOMO...
Multi-wall carbon nanotubes (MWNTs) grafted with alkyl chain were used for reinforcement of polypropylene (PP). For achieving excellent tensile properties, the as-prepared PP/MWNTs composites were subjected to a unique injection molding, as so-called dynamic packing injection molding, to induce a highly oriented structure with both PP chains and MWNTs aligned along the shear flow direction. Not only...
As a part of long-term project aimed at super polyolefin blends, in this work, we report the toughness and phase morphology of polypropylene (PP)/EPDM/SiO 2 ternary composites. Two processing methods were employed to prepare PP/elastomer/filler ternary composites. One was called one-step processing method, in which the elastomer and the filler directly melt blended with PP matrix. Another...
It is well known that a so-called “three-dimensional filler network structure” will be constructed in the polymer/layered silicate nanocomposites when the content of layered clay reaches a threshold value, at which the silicate sheets are incapable of freely rotating, due to physical jamming and connecting of the nanodispersed layered silicate. In this article, the effect of such clay network on the...
In this article, the injection-molded bars of isotactic polypropylene/organoclay nanocomposite with different clay contents have been obtained via dynamic packing injection molding (DPIM). The oriented microstructure including layered nanoparticles and PP lamellae has been inspected through 2D-WAXS analyses along the sample thickness of the molded bars. Depending on the clay content and sample thickness,...
The fibrillated linear low-density polyethylene (LLDPE)/isotactic polypropylene (iPP) fiber blends were subjected to dynamic packing injection molding (DPIM), in which the prolonged shear was exerted on the melt during solidification stage. Transcrystallization of LLDPE on PP fibers, with stacked lamellae parallel to each other and aligned approximately perpendicular to the long axial of the fibers,...
One of the most important findings in polymer-toughening is known as the critical matrix ligament thickness (τ c ) theory, which is directly related to both rubber concentration and average size of particles. All these studies assume that rubber particles are spherical and randomly distributed in the matrix. Rubber particles may be stretched and oriented along the shear flow direction in real...
The orientation of polymer chain has a great effect on its mechanical properties, therefore, it is always an important issue on how to characterize, accurately and quickly, the orientation of polymer chain during processing. In this article, according to the property that ultrasound travels in different velocities in anisotropic media, normal incident shear wave was utilized to explore the orientation...
In this paper, EPDM rubber and nano-SiO 2 particles were employed to modify PP simultaneously. Our goal was to control the distribution and dispersion of EPDM and nano-SiO 2 particles in PP matrix by using an appropriate processing method and adjusting the wettability of nano-SiO 2 particles toward PP and EPDM, so as to achieve a simultaneous enhancement of toughness and modulus...
Rigid inorganic filler has been long time used as a reinforcement agent for polymer materials. Recently, more work is focused on the possibility that using filler as a compatibilizer for immiscible polymer blends. In this article, we reported our efforts on the change of phase morphology and properties of immiscible polypropylene(PP)/polystyrene(PS) blends compatibilized with nano-SiO 2 particles...
Linear conservative dichroism has been investigated as a potential tool for tracking (in situ and in real time) the flow-induced microstructure of immiscible polymer blends. Dilute mixtures of poly(dimethylsiloxane) in poly(isobutene) and vice versa have been used as model systems. It is demonstrated that different mechanisms for structural changes can be identified with this technique: droplet deformation,...
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