Tuning gradient microstructures in immiscible polymer blends by viscosity ratio

Dan, Pan; Hufenus, Rudolf; Qin, Zongyi; Chen, Long; Gooneie, Ali

doi:10.1002/app.48165

Cited by 9 publications

(9 citation statements)

References 49 publications

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“…The emerged microstructure on the PS1/PP blend fiber surface mainly comes from the increasing mobility of the PS phase, which leads to the immigration of the PS phase to the fiber surface region, thus resulting in an enrichment of PS phases on the fiber surface. This phenomenon was also reported in other polymer blends during the melt extrusion process [ 14 , 15 , 43 ]. It must be mentioned that, in the case of the PS1/PP blend with 20% low-viscosity PS1 phases, the spinnability is poor and cannot take-up easily.…”

Section: Resultssupporting

confidence: 80%

“…Dispersed phases with different viscosities in one polymer matrix have different abilities to break-up, deform, and migrate during flowing. The effect of viscosity ratio and other parameters on the microrheological behaviors, such as droplet deformation, break-up, and immigration, and on the final morphology of polymer blend fibers has been studied in our previous studies [ 14 , 15 , 35 ] and many other experimental studies [ 26 , 36 , 37 , 38 , 39 ], where the viscosity ratio shows a dominant effect on the morphology of polymer blends. In this article, three sets of polymer blends with three different viscosity ratios were designed to build a surface structure on fiber.…”

Section: Resultsmentioning

confidence: 99%

“…Tsebrenko and co-authors’ studies also showed that specific fiber formation could be controlled by tailoring the rheological and interfacial properties [ 23 , 27 , 28 , 29 ]. Our previous studies found that unique gradient morphologies with long thin fibrils near the surface region and short large droplets near the center region of the filament, as well as the inverse pattern, can be produced by tunning the viscosity ratio of polymer blends and shear flow in capillary [ 14 , 15 ]. The formation mechanisms of gradient microstructures were also investigated based on capillary theory.…”

Section: Introductionmentioning

confidence: 99%

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Surface Structured Polymer Blend Fibers and Their Application in Fiber Reinforced Composite

et al. 2020

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Melt-spun surface structured fiber could be a large-scale versatile platform for materials with advanced surface function and local properties. Fibers with distinct surface and bulk structures are developed by tailoring the viscosity ratio and blend ratio of polymer component using the melt-spinning method. Spherical bulge and fibril groove structured fibers are obtained in different viscosity ratio and blend ratio systems. The interfacial bonding between fiber and matrix is improved due to the mechanical interlocking between the structured surface and matrix. The low-viscosity second phase stays as a spherical droplet even in high content. The second phase in matched- and high-viscosity ratio cases is deformed into fibril like droplet which causes an in-situ fibration of the second phase in polymer blend fiber with an enhanced mechanical property. This method provides a simple route to developing polymer materials with surface structure and appropriate mechanical properties to apply in textile and polymer fiber-reinforced composite materials.

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Section: Resultssupporting

confidence: 80%

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Surface Structured Polymer Blend Fibers and Their Application in Fiber Reinforced Composite

et al. 2020

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“…The observed cavities corresponding to the footprints of PP droplets indicate poor interfacial adhesion between PP and PS, caused by high interfacial tension between the blend constituents. Theoretically, a high viscosity ratio will result in large deformed droplets and a coarse morphology, whereas a low or matching viscosity ratio could result in fine fibrils and uniform morphology during melt-spinning [48]. There is visual evidence that interface detachment between both phases seems to occur most frequently for the fractured sample B0.9 (viscosity ratio, K > 1), where the viscosity of the PP particles is relatively higher than the PS matrix.…”

Section: Morphological Characterizationmentioning

confidence: 99%

Morphology, Rheology and Crystallization in Relation to the Viscosity Ratio of Polystyrene/Polypropylene Polymer Blends

et al. 2020

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Microfibrillar and droplet morphology of polypropylene (PP) phase dispersed in polypropylene (PS) was fabricated by using melt-extrusion. This morphology was obtained by introducing isotactic PP (20 wt.%) with different viscosity in the PS matrix (80 wt.%). Furthermore, the rheological properties of the blend investigated as a function of the viscosity ratio K. The variations in blend morphology were related to crystallization, melting properties, and viscoelasticity. The blends with K >> 1 develop a fine morphology with PP microfibrils along the flow direction, while diameters of the dispersed PP droplets gradually increase with lower values of K = 1, or K << 1. Crystallinity of the prepared blends significantly decreases compared to neat PP, while the microfibrillar morphology induces homogeneous crystallization with small crystallites. This is reflected in a decrease of the crystallization temperature, small loss in the crystallinity, and lower melting temperature of the PS80/PP20 blend compared to neat PP. The storage moduli, loss moduli, and complex viscosity are highest for the microfibrillar morphology that presents retarded relaxation. The rheological properties are dominated by the dispersed phase (K > 1), or matrix (K < 1). The variation in blend properties with microfibrillar morphology can be clearly distinguished from heterogeneous blends containing PP droplets, providing an efficient tool to create a binary blend with unique properties.

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“…The phase morphology of the PA phase can be easily valuated by observing the black stripe. Gradient morphology is developed by various injection methods and is affected by processing conditions [51,52]. As shown in Figure 8a, a thin shear layer (shear area marked with dotted lines and arrow) appears in A2(C).…”

Section: Resultsmentioning

confidence: 99%

Effects of Three Different Injection-Molding Methods on the Mechanical Properties and Electrical Conductivity of Carbon Nanotube/Polyethylene/Polyamide 6 Nanocomposite

Zhao

Zhu

2019

Polymers

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Morphological evolution under shear, during different injection processes, is an important issue in the phase morphology control, electrical conductivity, and physical properties of immiscible polymer blends. In the current work, conductive nanocomposites were produced through three different injection-molding methods, namely, conventional injection molding, multi-flow vibration injection molding (MFVIM), and pressure vibration injection molding (PVIM). Carbon nanotubes in the polyamide (PA) phase and the morphology of the PA phase were controlled by various injection methods. For MFVIM, multi-flows provided consistently stable shear forces, and mechanical properties were considerably improved after the application of high shear stress. Shear forces improved electrical property along the flow direction by forming an oriented conductive path. However, shear does not always promote the formation of conductive paths. Oscillatory shear stress from a vibration system of PVIM can tear a conductive path, thereby reducing electrical conductivity by six orders of magnitude. Although unstable high shear forces can greatly improve mechanical properties compared with the conventional injection molding (CIM) sample, oscillatory shear stress increases the dispersion of the PA phase. These interesting results provide insights into the production of nanocomposites with high mechanical properties and suitable electrical conductivity by efficient injection molding.

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Tuning gradient microstructures in immiscible polymer blends by viscosity ratio

Cited by 9 publications

References 49 publications

Surface Structured Polymer Blend Fibers and Their Application in Fiber Reinforced Composite

Surface Structured Polymer Blend Fibers and Their Application in Fiber Reinforced Composite

Morphology, Rheology and Crystallization in Relation to the Viscosity Ratio of Polystyrene/Polypropylene Polymer Blends

Effects of Three Different Injection-Molding Methods on the Mechanical Properties and Electrical Conductivity of Carbon Nanotube/Polyethylene/Polyamide 6 Nanocomposite

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