Microstructure Effect of Injection Molded Nanoparticle/Polymer Composites on their Resistivity

2012 ◽  
Vol 472-475 ◽  
pp. 1059-1062 ◽  
Author(s):  
Bao Feng Zhang ◽  
Ai Yun Jiang ◽  
De Bo Liu ◽  
Hai Hong Wu ◽  
Jing Chao Zou
Keyword(s):  
Polymer Composites ◽  
Large Scale ◽  
Flow Direction ◽  
Injection Pressure ◽  
Commercial Application ◽  
Molded Parts ◽  
Injection Molded ◽  
Microstructure Effect ◽  
The Relationship ◽  
Microstructural Effect

Although the progress has been achieved in conductive Nanoparticle/Polymer Composites(NPC), but there are many problems to be solved before their commercial application in a large scale, especially on their processing technology. The barriers include the dispersion of nanoparticle, the effect of nanoparticle concentration and interface on the overall properties of materials. In order to improve the application of NPC, the microstructural effect of injection molded NPC on its resistivity was investigated to build the relationship between the processing conditions and the properties in this paper. Composites used in the experiment were carbon black(CB)/polypropylene(PP). The microstructures of the injection molded parts at different positions were investigated with Scanning Electrical Microscope, and corresponsive properties were tested. The results showed that the distribution of CB nanoparticles changed with the injection pressure and had significant effect on the conductivity of the part. With the increase of injection pressure CB particles strongly oriented towards the flow direction of the polymer and thickness of oriented layer increased, which improve conductivity of the composites. The results also showed that crystallization was enhanced because of existence of nanoparticles, which should have increased the mechanical properties of the composite and decreased its resistivity because of the interfacial action between CB particles and polymer matrix.

Processing Effect of Injection Molded Nanoparticle/Polymer Composites on their Resistivity

2011 ◽  
Vol 314-316 ◽  
pp. 2531-2538
Author(s):  
Hai Hong Wu ◽  
Yong Feng Cheng ◽  
Ai Yun Jiang ◽  
Bao Feng Zhang
Keyword(s):  
Electrical Properties ◽  
Polymer Composites ◽  
Injection Pressure ◽  
Nano Particles ◽  
High Resistivity ◽  
Packing Pressure ◽  
High Injection Pressure ◽  
Injection Molded ◽  
Skin Zone ◽  
The Relationship

In order to improve the application of nano-particles/polymer composite, we investigated the relationship between microstructures and electrical properties on injection molded composites made from carbon black(CB) particles mixed with polypropylene(PP). Standard tensile specimens were injected under different processing conditions, after which, the specimens were cut off along the surface to observe the microstructures at different positions of the moldings. The microstructures were observed with Scanning Electrical Microscope(SEM), and electrical properties were measured by using a two-terminal standard resistor under DC condition at room temperature. The results showed that CB nano-particles may form the best conductive path under the higher packing pressure combined higher injection pressure. If packing pressure is low, the resistivities at the skin zone loaded by high injection pressure are smaller than low injection pressure, but the resistivities increase at the sub-skin zone. We found that the sub-skin zone is a high resistivity district which would expand with higher injection pressure matched lower packing pressure. Contrast to the injection molded polymer whose microstructural orientation is stronger at the sub-skin zones, injection molded CB particles/polymer composites develop strong oriented microstructures at the core zones in stead of the skin or sub-skin zones due to CB particles’ migration.

Fiber Orientation in Injection-Compression Molded Short-Fiber-Reinforced Polypropylene Parts

2009 ◽  
Author(s):  
Han-Xiong Huang ◽  
Can Yang ◽  
Kun Li
Keyword(s):  
Fiber Orientation ◽  
Flow Direction ◽  
Processing Parameters ◽  
Short Fiber ◽  
Fiber Reinforced ◽  
Compression Force ◽  
Time Compression ◽  
Compression Time ◽  
Molded Parts ◽  
Injection Molded

Four processing parameters, including compression force, compression time, compression distance, and delay time, were investigated in terms of their effects on the fiber orientation in injection-compression molded (ICM) short-fiber-reinforced polypropylene parts. The results reveal that the fiber orientation pattern in ICM parts is different from that in conventional injection molded parts. Compression force plays an important role in determining the fiber orientation, whereas the effect of compression time can be neglected. Moreover, the fiber orientation changes obviously in the width direction, with most fibers arranging orderly in the flow direction at positions near the mold cavity wall.

Study on the Online Monitoring of Burn Marks by Gas Sensor

2017 ◽  
Vol 11 (1) ◽  
pp. 112-119 ◽  
Author(s):  
Yoshio Fukushima ◽  
◽  
Takashi Suzuki ◽  
Kouki Onda ◽  
Hidekazu Komatsu ◽  
...  
Keyword(s):  
Gas Sensor ◽  
Gas Sensors ◽  
Online Monitoring ◽  
Gas Generation ◽  
Great Demand ◽  
Molded Parts ◽  
Injection Molded ◽  
The Relationship

Burn marks are serious defects in injection-molded parts that can result in many defective products. There is thus a great demand for effective systems to reduce these defects in injection-molded products. In this study, we investigate the relationship between gas generation and molding conditions using gas sensors. The results show that gas sensors can be used to monitor burn marks.

Effect of Molding Parameters on the Interface Morphology of Metal Co-Injection Molding

2011 ◽  
Vol 189-193 ◽  
pp. 2939-2944
Author(s):  
Hao He ◽  
Yi Min Li ◽  
Guang Yao Wang
Keyword(s):  
Rheological Properties ◽  
Delay Time ◽  
Flow Direction ◽  
Injection Velocity ◽  
Interface Morphology ◽  
Key Factors ◽  
The Core ◽  
Molded Parts ◽  
Injection Molded ◽  
Injection Temperature

In the present study, the effect of injection temperature, velocity and delay time on the interface morphology of the co-injection molded plates was studied. The results showed that the core penetration parallel to the flow direction becomes less as the skin injection velocity and temperature increases and delay time decreases. Among the parameters, temperature was the most significant in affecting the interface morphology, followed by delay time, while injection velocity seemed to play no significant role. The results were analyzed by taking account of rheological properties of the two feedstocks. Calculations and comparisons of viscosity ratios encountered in experiments were made. It was demonstrated the differences in the rheological properties of the metal feedstocks involved are key factors in determining the interface morphology of the molded parts.

Study of the effect on conductivity and its uniform distribution in injection molded composite polymer bipolar plate

e-Polymers ◽  
2007 ◽  
Vol 7 (1) ◽  
Author(s):  
Chen Shia-Chung ◽  
Shih Ming-Yi ◽  
Lin Yi-Chang
Keyword(s):  
Flow Direction ◽  
Mold Temperature ◽  
Bipolar Plate ◽  
Surface Conductivity ◽  
Temperature Control System ◽  
Melt Flow ◽  
Molded Part ◽  
Molded Parts ◽  
Fluid Channel ◽  
Injection Molded

AbstractIn this study, PPS blended with as high as 50 wt% carbon fiber were injection molded. Effects of molding conditions as well as the melt flow condition parallel and perpendicular to fluid channel on the surface conductivity was investigated. It was found that mold temperature affects the surface conductivity of molded parts significantly. Using a variable mold temperature control system based on electromagnetic induction heating, the conductivity of the molded part increase by about 152% when the peak mold temperature increases from 120 °C to 210 °C. The channel layout also helps the fiber to orient more randomly leading to an increase in the conductivity. The channel design parallel to melt flow increases the conductivity by 152% and when it is perpendicular to melt flow, the conductivity increases by 95%. Channel layout perpendicular to melt flow direction provides more influence on the fiber reorientation than that of the parallel design.

Optimization Design of Injection Molded Parts Based on Mold Flow

2012 ◽  
Vol 224 ◽  
pp. 97-100
Author(s):  
Jun Kai Yang ◽  
Yun Jie Xu
Keyword(s):  
Optimization Design ◽  
Injection Pressure ◽  
Clamping Force ◽  
Molded Parts ◽  
Injection Molded ◽  
Mold Flow

PC injection molded parts are taken as an example. Mold flow software is used to predict the filling condition of the product, estimate the injection pressure and clamping force required to mold this product and its warpage, and find elements that cause the warpage so as to change the mold structure, reduce warpage and improve the quality of the product.

Effects of Gate Locations on the Tensile Strength of Injection Molded Weld Lines

2013 ◽  
Vol 561 ◽  
pp. 64-69
Author(s):  
Yu Mei Ding ◽  
Xiao Hua Wang ◽  
Peng Cheng Xie ◽  
You Chen Zhang ◽  
Wei Min Yang
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Mechanical Test ◽  
Injection Pressure ◽  
Melt Temperature ◽  
Injection Speed ◽  
Appearance Quality ◽  
Study Results ◽  
Molded Parts ◽  
Injection Molded

As unfavorable molding defect, weld lines often result in reduced mechanical properties and poor appearance quality of injection molded parts. In this present work, effects of gate locations on the tensile strength of weld lines were investigated by changing the distances between two gates in 10mm, 20mm and 25mm, respectively. Test specimens were prepared with an all-electrical injection molding machine under different process parameters (injection speed, injection pressure and melt temperature). Visualization method and scanning electron microscope (SEM) were employed to further discuss mechanical test results. Study results indicated that tensile strength of injection molded weld lines was lessened as the increase of gate distances. Higher injection speed, higher injection pressure and lower melt temperature induced to lower weldline tensile strength whatever the gate locations were. Study results also illustrated that it was gate location rather than molding conditions had the most decisive influence on the weldline mechanical properties.

scholarly journals Tailoring P-N Conversion in All-solid-state Polymer Composites with A Record Ionic Thermopower

2021 ◽  
Author(s):  
Cheng Chi ◽  
Meng An ◽  
Xin Qi ◽  
Yang Li ◽  
Ruihan Zhang ◽  
...  
Keyword(s):  
Solid State ◽  
Polymer Composites ◽  
High Voltage ◽  
High Performance ◽  
Large Scale ◽  
Ambient Air ◽  
Organic Polymer ◽  
Cyclic Stability ◽  
Simulation Results ◽  
The Relationship

Abstract All-solid-state organic polymer composites are promising ionic thermoelectric (i-TE) materials, however, the transition from aqueous to organic gelation always sacrifices their thermoelectric performance, especially the n-type thermopowers are severely unexplored, leaving the unrealized large-scale application of p-n integrated i-TE devices. Herein, we successfully developed all-solid-state PVDF-HFP/NaTFSI/PC (PhNP) with ultrahigh thermopower (Si) of +20 mV K-1. The experimental and molecular simulation results detailly specified the relationship between the interactions among ions and polymers and the highly enhanced thermopower. Meanwhile, a major scientific breakthrough in p-n conversion from +20 to -6 mV K-1 was achieved by incorporating tris(pentafluorophenyl)borane (TPFPB) to capture Na+ and TFSI- anions dominating the thermodiffusion process. As a result, an all-solid-state i-TE generator generated a high voltage over 2.6 V at ΔT=10 K and exhibited excellent cyclic stability under ambient air condition employing only 13 pairs of p-n couples, showing great potential for developing high-performance i-TE systems.

Relationship between total plasma homocysteine and the risk of aneurysms – a meta-analysis

VASA ◽  
2020 ◽  
pp. 1-6
Author(s):  
Hanji Zhang ◽  
Dexin Yin ◽  
Yue Zhao ◽  
Yezhou Li ◽  
Dejiang Yao ◽  
...  
Keyword(s):  
Large Scale ◽  
Meta Analysis ◽  
Single Species ◽  
Total Plasma ◽  
Control Groups ◽  
Randomized Controlled ◽  
Randomized Controlled Studies ◽  
The Difference ◽  
The Relationship ◽  
Healthy Participants

Summary: Our meta-analysis focused on the relationship between homocysteine (Hcy) level and the incidence of aneurysms and looked at the relationship between smoking, hypertension and aneurysms. A systematic literature search of Pubmed, Web of Science, and Embase databases (up to March 31, 2020) resulted in the identification of 19 studies, including 2,629 aneurysm patients and 6,497 healthy participants. Combined analysis of the included studies showed that number of smoking, hypertension and hyperhomocysteinemia (HHcy) in aneurysm patients was higher than that in the control groups, and the total plasma Hcy level in aneurysm patients was also higher. These findings suggest that smoking, hypertension and HHcy may be risk factors for the development and progression of aneurysms. Although the heterogeneity of meta-analysis was significant, it was found that the heterogeneity might come from the difference between race and disease species through subgroup analysis. Large-scale randomized controlled studies of single species and single disease species are needed in the future to supplement the accuracy of the results.

New ''Cold War''

2020 ◽  
pp. 27-34
Author(s):  
Vladimir Batiuk
Keyword(s):  
Cold War ◽  
Nuclear Weapons ◽  
Armed Conflict ◽  
Large Scale ◽  
Arms Race ◽  
Ideological Struggle ◽  
Nuclear Arms Race ◽  
The Cold War ◽  
The Relationship ◽  
Nuclear Arms

In this article, the ''Cold War'' is understood as a situation where the relationship between the leading States is determined by ideological confrontation and, at the same time, the presence of nuclear weapons precludes the development of this confrontation into a large-scale armed conflict. Such a situation has developed in the years 1945–1989, during the first Cold War. We see that something similar is repeated in our time-with all the new nuances in the ideological struggle and in the nuclear arms race.

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