scholarly journals Effect of Processing Techniques on the Microstructure and Mechanical Performance of High-Density Polyethylene

Polymers ◽  
2021 ◽  
Vol 13 (19) ◽  
pp. 3346
Author(s):  
Edgar Mejia ◽  
Nizamudeen Cherupurakal ◽  
Abdel-Hamid I. Mourad ◽  
Sultan Al Hassanieh ◽  
Mohamed Rabia
Keyword(s):  
Injection Molding ◽  
High Density Polyethylene ◽  
Mechanical Performance ◽  
High Density ◽  
Degree Of Crystallinity ◽  
Uniaxial Tensile ◽  
Premature Failure ◽  
Characterization Techniques ◽  
Uniaxial Tensile Testing ◽  
Processing Techniques

The versatility of high-density polyethylene (HDPE) makes it one of the most used polymers for vast applications ranging from food packaging to human implants. However, there still is confusion regarding the proper selection of processing techniques to produce HDPE specimens for high-end applications. Herein, we compare the processing of HDPE by two relevant techniques: compression and injection molding. The fabricated samples were studied using uniaxial tensile testing to determine their mechanical performance. Furthermore, the microstructure of samples was analyzed using different characterization techniques. Compression-molded specimens recorded a higher degree of crystallinity (DC) using two different characterization techniques such as differential scanning calorimetry (DSC) and X-ray diffraction (XRD). With this information, critical processing factors were determined, and a general structure–property relationship was established. It was demonstrated that having a higher DC resulted in higher yield strength and Young’s modulus. Furthermore, premature failure was observed in the injection-molded specimens, resulting in lower mechanical performance. This premature failure was caused due to flow marks observed using scanning electron microscopy (SEM). Therefore, it is concluded that compression molding produces superior samples compared to injection molding.

scholarly journals MECHANICAL CHARACTERIZATION OF PA 12 AND HDPE PIPES BEFORE AND AFTER AGING IN WATER AT TWO DIFFERENT TEMPERATURES

2021 ◽  
Vol 9 (1) ◽  
pp. 248-256
Author(s):  
J.A. dos Santos ◽  
R.C. Tucunduva ◽  
J.R.M. D’Almeida
Keyword(s):  
High Density Polyethylene ◽  
Mechanical Performance ◽  
High Density ◽  
Effect Of Temperature ◽  
Polyamide 12 ◽  
Polyethylene Pipes ◽  
Before And After ◽  
Different Temperatures ◽  
Deterioration Process ◽  
Combined Action

Polymer pipes are being widely used by many industrial segments. Although not affected by corrosion, the mechanical performance of these pipes can be reduced due to exposure to temperature, UV radiation and by contact with various fluids. Depending on the deterioration process, embrittlement or plasticization may occur, and the service life of the pipe can be severely reduced. In this work, the combined action of temperature and water upon the mechanical performance of polyamide 12 and high-density polyethylene pipes is evaluated. Destructive and non-destructive techniques were used and the performance of both materials was compared. Both polymers were platicized by the effect of water. However, for high density polyethylene the effect of temperature was more relevant than for polyamide. This behavior was attributed to the dependence of the free volume with the markedly different glass transition temperature of the polymers and the temperatures of testing.

Extension of the orientation region of high density polyethylene molded by gas-assisted injection molding: control of the thermal field

2014 ◽  
Vol 63 (12) ◽  
pp. 1997-2007 ◽  
Author(s):  
Xiao-Chao Xia ◽  
Quan-Ping Zhang ◽  
Long Wang ◽  
Shan He ◽  
Jian-Ming Feng ◽  
...  
Keyword(s):  
Injection Molding ◽  
High Density Polyethylene ◽  
Thermal Field ◽  
High Density

Fabrication and characterization of microwave cured high-density polyethylene/carbon nanotube and polypropylene/carbon nanotube composites

2019 ◽  
Vol 53 (15) ◽  
pp. 2091-2104 ◽  
Author(s):  
Gaurav Arora ◽  
Himanshu Pathak ◽  
Sunny Zafar
Keyword(s):  
Carbon Nanotube ◽  
High Density Polyethylene ◽  
High Density ◽  
Uniaxial Tensile ◽  
Uniaxial Tensile Test ◽  
X Ray Diffraction ◽  
X Ray ◽  
Nanotube Composites ◽  
Carbon Nanotube Composites ◽  
Scanning Electron

Carbon nanotubes have been used as reinforcements in polymers due to their high elasticity, flexibility, and thermal conductivity. In this study, pellets of high-density polyethylene +20 wt% carbon nanotube and polypropylene +20 wt% carbon nanotube were cured using microwave energy. X-ray diffraction, differential scanning calorimetry, thermogravimetric analysis, uniaxial tensile test, and scanning electron microscopy was used to study morphology, thermal stability, and mechanical performance of the microwave-cured composites. X-ray diffraction analysis confirmed the bonding between the polymer and carbon nanotube as the peaks shifted and intensified. From the thermal study, it was observed that melting point of the composites is affected by microwave curing and the crystallinity of high-density polyethylene/carbon nanotube and polypropylene/carbon nanotube changed by 57.67% and 47.28%, respectively. Results of the uniaxial tensile test indicated that Young’s modulus of microwave cured high-density polyethylene/carbon nanotube and polypropylene/carbon nanotube composites were improved by 295% and 787.8%, respectively. Scanning electron microscopic fractography shows the stretching of polymer over-lapped on carbon nanotubes in the direction of the applied load.

Mold replication in injection molding of high density polyethylene

2020 ◽  
Vol 60 (10) ◽  
pp. 2459-2469
Author(s):  
Fabrizio Quadrini ◽  
Denise Bellisario ◽  
Loredana Santo ◽  
Luana Bottini ◽  
Alberto Boschetto
Keyword(s):  
Injection Molding ◽  
High Density Polyethylene ◽  
High Density
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