Ultrasonic oscillations effect on rheological and processing properties of metallocene‐catalyzed linear low density polyethylene

Wu, Hong; Guo, Shaoyun; Chen, Guangshun; Lin, Jia; Chen, Wei; Wang, Hongtao

doi:10.1002/app.12859

Cited by 22 publications

(25 citation statements)

References 49 publications

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“…23 The maximum power output and fixed frequency of the generator were 300 W and 20 kHz. The POE was mixed with MAH, DCP, and St which were dissolved in acetone before extrusion.…”

Section: Samples Preparationmentioning

confidence: 99%

Enhanced compatibility of PA6/POE blends by POE‐g‐MAH prepared through ultrasound‐assisted extrusion

Xie

Bao

et al. 2010

J of Applied Polymer Sci

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The effects of POE-g-MAH, prepared through different methods, on morphology and properties of PA6/POE/POE-g-MAH blends are summarized in this article. The grafting degree of POE-g-MAH can be increased through the ultrasound-assisted extrusion. Experimental results showed that the addition of POE-g-MAH can increase the mechanical properties of the PA6/ POE blend and decrease the particle size of POE dispersed phase in PA6 matrix due to the compatibilization by POE-g-MAH. The PA6/POE blend compatibilized by POE-g-MAH prepared through the ultrasound-assisted extrusion has smaller particle size of POE dispersed phase and higher notched Izod impact strength than that by POE-g-MAH with similar grafting degree initiated only by peroxide. This result is ascribed to some anhydride rings attached to the chain terminus of POE due to ultrasound initiation. Rheological and Molau test results also showed enhanced compatibilization of POE-g-MAH prepared through the ultrasound-assisted extrusion on the PA6/POE blend due to a structural difference of POE-g-MAH.

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“…23 The maximum power output and fixed frequency of the generator were 300 W and 20 kHz. The POE was mixed with MAH, DCP, and St which were dissolved in acetone before extrusion.…”

Section: Samples Preparationmentioning

confidence: 99%

Enhanced compatibility of PA6/POE blends by POE‐g‐MAH prepared through ultrasound‐assisted extrusion

Xie

Bao

et al. 2010

J of Applied Polymer Sci

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“…If we oscillated the nozzle up and down, the diameter of the strand slightly increased. This is because the viscosity of the PCL solution decreased due to the oscillation of the nozzle [22][23][24]. The vibration force applied to the polymer solution reduced the van der Waals force connecting the macromolecules of the polymer solution, so that the viscous force between the macromolecules decreased.…”

Section: Resultsmentioning

confidence: 95%

Fabrication and characterization of 3D scaffold using 3D plotting system

Lee

Park

et al. 2010

Chin. Sci. Bull.

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In this paper, we design and fabricate a 3D scaffold using rapid prototyping (RP) technology for tissue engineering. The scaffold should have a three-dimensional interconnected pore network. We fabricate a polycaprolactone (PCL) scaffold with interconnecting pores and uniform porosity for cell ingrowth using a 3D plotting system. In order to keep the three dimensional shape under mechanical loading while implanted, we design an oscillating nozzle system to increase elastic modulus and yield strength of PCL strand. We characterize the influence of pore geometry, compressive modulus of the scaffold, elastic modulus and yield strength of the strand using SEM, dynamical mechanical analysis (DMA) and Nano-UTM. Finally the cell responses on scaffolds are observed. 3D scaffold, polycaprolatone (PCL), rapid prototyping (RP), oscillating nozzle, tissue engineeringCitation: Lee J-H, Park S-A, Park K E, et al. Fabrication and characterization of 3D scaffold using 3D plotting system. Chinese Sci Bull, 2010, 55: 94-98, A 3D scaffold for tissue regeneration is a supporting structure to hold cells in place. It should have a three-dimensional interconnected pore network for cell growth, nutrient delivery, and metabolic waste. And it also needs good mechanical properties to keep the three-dimensional shape under mechanical loading while implanted [1,2]. Conventional scaffold fabrication methods include solvent casting and particle leaching [3], gas foaming [4], melt molding [5], fiber meshes and fiber bonding [6,7], phase separation [8], and freeze drying [9,10]. But there are several limitations to the conventional scaffold fabrication methods. These methods cannot precisely control pore size, interconnection of pores, or pore geometry.In order to overcome these limitations, a rapid prototyping (RP) system has been proposed to solve these problems [1,2]. The RP system can control the pore size, pore geometry, and interconnection of pores in the scaffold. The scaffold fabricated by a RP system has a three-dimensional interconnected pore network, so it can transport more oxygen and nutrients deep into the scaffold. Metabolic waste can be easily transported within the interconnected pore network. There are a lot of methods for the fabrication of the RP scaffold, such as selective laser sintering (SLS) [11], fused deposition modeling (FDM) [12], stereolithography (SLA) [13], 3D printing [14] and 3D plotting [15]. As the 3D scaffold is a supporting structure, the mechanical properties of the scaffold are of great importance, especially for the field of bone tissue engineering. Some of the work has been done to analyze the mechanical properties of the 3D scaffold made by particle leaching method [16][17][18]. However, few studies have been done to characterize and improve the mechanical properties of the 3D scaffold made by an RP system.In this paper, we design and fabricate a 3D PCL scaffold using a PR system-3D plotter. In order to increase the elastic modulus and yield strength of the PCL strands in the

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“…Our main experiment is a specially designed ultrasound‐assisted extrusion system developed in our lab [28]. The die, which is constructed by steel, includes a special horn serving as a capillary, whose length/diameter ( L / D ) ratio is fixed at 8.…”

Section: Methodsmentioning

confidence: 99%

“…In recent years, ultrasound technology has been developed to improve the processing properties of polymers during the extrusion [19–23]. In our laboratory, different kinds of polyethylene melts such as HDPE, LLDPE, and metallocene‐catalyzed linear low‐density polyethylene (mLLDPE), have been studied during ultrasound‐assisted extrusion [24–28]. It was found that the die pressure and apparent viscosity of polyethylene melts in the extrusion were greatly decreased with increasing ultrasound power.…”

Section: Introductionmentioning

confidence: 99%

Enhanced flow behaviors of metallocene‐catalyzed linear low‐density polyethylene during ultrasound‐assisted extrusion

Bao

Guo

2010

Polymer Engineering & Sci

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The effect of ultrasound on flow behaviors of metallocene‐catalyzed linear low‐density polyethylene (mLLDPE) melt in capillary‐like die during the extrusion is investigated in this article. The rise in die temperature is found with increasing ultrasound power, especially at lower initial die temperature. At the same die temperature, the presence of ultrasound can decrease the apparent viscosity and the viscous flow activation energy of mLLDPE melt then increase its slip velocity at the capillary wall in the die. The flow behavior of mLLDPE melt is enhanced during ultrasound‐assisted extrusion as the presence of ultrasound can enhance the mobility and the orientation of entangled segments. It is also found that ultrasound can break the dispersed phase of mLLDPE/polyolefin elastomer (POE) blend into small pieces thus improve the homogeneous dispersion of POE phase in mLLDPE matrix. A possible mechanism for enhanced flow behaviors of mLLDPE melt because of the presence of ultrasound is also proposed. POLYM. ENG. SCI., 2010. © 2010 Society of Plastics Engineers

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Ultrasonic oscillations effect on rheological and processing properties of metallocene‐catalyzed linear low density polyethylene

Cited by 22 publications

References 49 publications

Enhanced compatibility of PA6/POE blends by POE‐g‐MAH prepared through ultrasound‐assisted extrusion

Enhanced compatibility of PA6/POE blends by POE‐g‐MAH prepared through ultrasound‐assisted extrusion

Fabrication and characterization of 3D scaffold using 3D plotting system

Enhanced flow behaviors of metallocene‐catalyzed linear low‐density polyethylene during ultrasound‐assisted extrusion

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