Effects of molding on property of thermally conductive and electrically insulating polyamide 6–based composite

2018 ◽  
Vol 32 (9) ◽  
pp. 1190-1203 ◽  
Author(s):  
Xuping Yang ◽  
Wenbin Yang ◽  
Jinghui Fan ◽  
Juying Wu ◽  
Kai Zhang
Keyword(s):  
Thermal Conductivity ◽  
Tensile Strength ◽  
Injection Molding ◽  
Annealing Time ◽  
Polyamide 6 ◽  
Molding Pressure ◽  
Hot Press ◽  
Molding Method ◽  
Thermally Conductive ◽  
Press Molding

Thermally conductive and electrically insulating polyamide 6 (PA6) matrix quaternary composites were prepared by hot press molding and injection molding, respectively. The quaternary composites were composed of zero-dimensional aluminum oxide particle, one-dimensional silicon carbide whisker, two-dimensional flake graphite, and PA6 resin matrix. Morphology, structure, density, thermal conductivity, volume electrical resistivity, and tensile strength of two types of composites were characterized by scanning electron microscopy, X-ray diffractometer, thermal conductivity tester, high resistance micro-current tester, and tensile tester. The results showed that crystallinity, thermal conductivity, density, and tensile strength of hot press molding samples were superior to those of samples made by injection molding method. This is due to that hot press molding method can provide higher molding pressure and longer annealing time than injection molding. The mechanism could be explained that the performances of the composites were promoted by increasing molding pressure and annealing time.

Increasing heat transfer performance of thermoplastic polyurethane by constructing thermal conduction channels of ultra-thin boron nitride nanosheets and carbon nanotubes

2020 ◽  
Vol 44 (43) ◽  
pp. 18823-18830
Author(s):  
Yue Ruan ◽  
Nian Li ◽  
Cui Liu ◽  
Liqing Chen ◽  
Shudong Zhang ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Thermal Conductivity ◽  
Carbon Nanotubes ◽  
Tensile Strength ◽  
Thermal Conduction ◽  
Heat Transfer Performance ◽  
Thermoplastic Polyurethane ◽  
Transfer Performance ◽  
Boron Nitride Nanosheets ◽  
Thermally Conductive

The TPU-based thermally conductive composite reaches a thermal conductivity of 1.35 W m−1 K−1 and increases the tensile strength by at least 300%.

scholarly journals Carbon Fiber Reinforced Thermoplastics Molding by Using Direct Resistance Heating to Carbon Nanofilaments Grafted Carbon Fiber

2019 ◽  
Vol 3 (1) ◽  
pp. 14 ◽  
Author(s):  
Kazuto Tanaka ◽  
Ririko Habe ◽  
Masayoshi Tanaka ◽  
Tsutao Katayama
Keyword(s):  
Carbon Fiber ◽  
Void Content ◽  
Resistance Heating ◽  
Fiber Reinforced ◽  
Hot Press ◽  
Molding Method ◽  
Reinforced Thermoplastics ◽  
Reinforcing Fiber ◽  
Fiber Reinforced Thermoplastics ◽  
Press Molding

In the automobile industry, carbon fiber reinforced thermoplastics (CFRTP) have attracted attention as potential materials to reduce the weight of the automobile body. In order to apply CFRTP to mass-produced automobile parts, it is necessary to develop the reduction of molding time and the impregnation method into the carbon fiber (CF) for the thermoplastic resin, which has relatively high viscosity. Although the conventional hot press molding uses only the heat transfer from the mold to the molding materials, it is expected to develop a new molding method for CFRTP using heat generation of the materials themselves to overcome these issues. As a method of heating the carbon fiber, there is a direct resistance heating method, in which carbon fiber is directly energized and heated by Joule heat. We have developed resistance welding methods in which carbon nanotube (CNT) grafted carbon fiber (CNT-CF) is used for the heating elements, and revealed that the higher welded strength is obtained by using CNT-CF instead of CF. Therefore, the carbon nanofilaments (CNF) grafted carbon fiber (CNF-CF) including CNF-CF is expected not only to be used as a resistance heating medium at the time of joining but also as a reinforcing fiber and as a self-heating member at the time of molding. In this study, we develop the CFRTP molding method by using direct resistance heating to CNF-CF in the hot press molding. CFRTP ([0°]20) with the volume fractions (Vf) of 40% are molded by conventional hot press and hot press with direct resistance heating to reinforcing fiber. CF or CNF-CF is used for reinforcement. CFRTP molded by hot press with direct resistance heating to CNF-CF indicated lower void content than CFRTP molded by hot press with direct resistance heating to CF. Compared to CFRTP molding by only hot press, hot press molding with direct resistance heating to CNF-CF can mold CFRTP with low void content.

Product Strength and Orientation Manipulation via Vibration-Assisted Injection Molding

2002 ◽  
Author(s):  
David C. Angstadt ◽  
John P. Coulter
Keyword(s):  
Thermal Conductivity ◽  
Tensile Strength ◽  
Injection Molding ◽  
Molecular Orientation ◽  
Polymer Melt ◽  
Polymer Processing ◽  
Shear Yielding ◽  
Processing Methods ◽  
Improve Product

This investigation focuses on determining why polystyrene ASTM specimens exhibit an increase in tensile strength when processed by vibration assisted injection molding (VAIM) while polycarbonate parts do not. VAIM is one of several polymer processing methods that attempt to improve product properties via manipulation of the polymer melt. Observation of birefringence patterns in VAIM processed polystyrene samples show a significant impact on molecular orientation. The same studies were conducted on opaque polycarbonate and were unable to determine the degree of molecular orientation via birefringence measurement. It was theorized that VAIM did not produce significant orientation due to its higher thermal conductivity and stiffer backbone. It has been determined by this investigation that VAIM processing does impart significant molecular orientation in polycarbonate specimens but still does not increase its UTS. It is proposed that increased molecular orientation induced by VAIM processing inhibits crazes from growing into cracks. VAIM therefore favors polymers that fail by crazing (e.g., polystyrene) rather than those that fail by shear yielding (e.g., polycarbonate).

Metal Injection Molding Method of Ni-Free Austenitic Stainless Steel II - Microstructure and Mechanical Properties

2007 ◽  
Vol 26-28 ◽  
pp. 19-22
Author(s):  
Midori Komada ◽  
Yoshikazu Kuroda ◽  
Ryo Murakami ◽  
Noriyuki Tsuchida ◽  
Yasunori Harada ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Surface Layer ◽  
Injection Molding ◽  
Nitrogen Content ◽  
Tensile Tests ◽  
Metal Injection Molding ◽  
Homogeneous Microstructure ◽  
Molding Method ◽  
Microstructure And Mechanical Properties

Microstructure and mechanical properties of high nitrogen steels whose chemical composition were Fe-17Cr-12Mn-3Mo and that was produced by using metal injection molding method and nitrogen absorption methods were examined. A compact which is furnace cooled from 1573 K has a brittle surface layer with high chromium and nitrogen contents but the surface layer disappears when the compact is held at 1473 K. The compact which is furnace cooled at 1473 K is observed precipitates in the grains and the grain boundary, while the compact which is quenched at 1473 K shows homogeneous microstructure. In the heat treatments at 1473 K for 2, 5, and 10 h, the nitrogen content becomes higher with increasing of holding time. In the holding times of 5 and 10 h, the microstructure is austenite. In the tensile tests, tensile strength becomes larger with increasing of nitrogen content. In the specimen which is conducted the heat treatment at 1473 K for 10 h, tensile strength is about 1,000 MPa and elongation is 80 %, which shows better balance of strength and elongation than SUS304 and SUS316 steels.

scholarly journals Effect of the Compounding Conditions of Polyamide 6, Carbon Fiber, and Al2O3 on the Mechanical and Thermal Properties of the Composite Polymer

Materials ◽  
2019 ◽  
Vol 12 (18) ◽  
pp. 3047 ◽  
Author(s):  
Young Shin Kim ◽  
Jae Kyung Kim ◽  
Euy Sik Jeon
Keyword(s):  
Thermal Conductivity ◽  
Thermal Properties ◽  
Injection Molding ◽  
Mechanical Strength ◽  
Melt Flow Index ◽  
Polyamide 6 ◽  
Extrusion Process ◽  
Flow Index ◽  
Process Conditions ◽  
Mechanical And Thermal Properties

Among the composite manufacturing methods, injection molding has higher time efficiency and improved processability. The production of composites via injection molding requires a pre-process to mix and pelletize the matrix polymer and reinforcement material. Herein, we studied the effect of extrusion process conditions for making pellets on the mechanical and thermal properties provided by injection molding. Polyamide 6 (PA6) was used as the base, and composites were produced by blending carbon fibers and Al2O3 as the filler. To determine the optimum blending ratio, the mechanical properties, thermal conductivity, and melt flow index (MI) were measured at various blending ratios. With this optimum blending ratio, pellets were produced by changing the temperature and RPM conditions, which are major process variables during compounding. Samples were fabricated by applying the same injection conditions, and the mechanical strength, MI values, and thermal properties were measured. The mechanical strength increased slightly as the temperature and RPM increased, and the MI and thermal conductivity also increased. The results of this study can be used as a basis for specifying the conditions of the mixing and compounding process such that the desired mechanical and thermal properties are obtained.

scholarly journals Fabrication of Micro-Groove on the Surface of CFRP to Enhance the Connection Strength of Composite Part

Polymers ◽  
2021 ◽  
Vol 13 (22) ◽  
pp. 4039
Author(s):  
Bin Xu ◽  
Meng-Yang Wei ◽  
Xiao-Yu Wu ◽  
Lian-Yu Fu ◽  
Feng Luo ◽  
...  
Keyword(s):  
Tensile Strength ◽  
Injection Molding ◽  
Polymer Material ◽  
Lightweight Design ◽  
Injection Pressure ◽  
Polyamide 6 ◽  
Compression Molding ◽  
Connection Strength ◽  
Molding Process ◽  
Composite Part

Carbon fiber-reinforced plastic (CFRP) has the advantages of being light weight, high strength, and corrosion resistant. At present, it is widely used in the lightweight design of automobile parts. The manufacturing of lightweight parts inevitably involves the connection between CFRP and the polymer material. The connection strength between CFRP and the polymer material significantly affects the service life of the composite parts. Taking CFRP and polyamide 6 (PA6) injection-molded composite parts as an example, this paper proposed a technological method to enhance the connection strength between CFRP and PA6. The proposed method was to fabricate micro-groove structures on the CFRP surface by compression molding. These micro-groove structures effectively increased the injection-molding area of the composite parts, thus enhancing the connection strength between CFRP and PA6. This paper presented a detailed study on the compression-molding process of micro-grooves on the CFRP surface, and successfully obtained the appropriate parameters. Finally, PA6 was used for injection molding on the CFRP with micro-grooves at an injection pressure of 8 MPa, an injection temperature of 240 °C, a holding pressure of 5 MPa, and a holding time of 2.5 s. The experimental results show that the micro-groove array structures on the CFRP surface could effectively improve the tensile strength of the connection interface in the composite parts. Compared with the composite part without micro-grooves, the tensile strength of the composite part with micro-grooves was increased by 80.93%. The composite parts prepared in this paper are mainly used in automobile interiors and the research results of this paper meet the actual needs of the enterprise.

Study on Glass Fiber Reinforced EP/PSF Insulating and Thermally Conductive Composite Filled with BN Particles

2013 ◽  
Vol 341-342 ◽  
pp. 153-156
Author(s):  
Fan Xie ◽  
Shu Hua Qi ◽  
Jun Peng Li
Keyword(s):  
Thermal Conductivity ◽  
Thermal Stability ◽  
Composite Materials ◽  
Glass Fiber ◽  
Glass Fiber Reinforced ◽  
The Matrix ◽  
Thermally Conductive ◽  
Modified Epoxy ◽  
Thermal Stability Of ◽  
Press Molding

Polysulfone modified epoxy resin was chosen as the matrix of composite materials. The epoxy/glass fiber/boron nitride composite materials were prepared by heat press molding. The effect of different size and content of BN on the thermal, mechanical, electrical properties and thermal stability of the composite was investigated. The results showed that thermal conductivity and thermal stability of the composite increased with the content of the BN particles, the thermal conductivity of the composite reached 0.672W/m·K when filled with 1μm BN at 20 wt.%. Impact strength and flexure strength of the composite increased initially and then decreased with the increasing content of BN. The electrical insulating property of the composite remained with the content of 20 wt.% BN.

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