Reinforcing of low-density polyethylene by cellulose extracted from agricultural wastes

2018 ◽  
Vol 53 (2) ◽  
pp. 219-225 ◽  
Author(s):  
Shadi Sawalha ◽  
Raed Ma'ali ◽  
Omar Surkhi ◽  
Mohammad Sawalha ◽  
Bayan Dardouk ◽  
...  

Cellulosic materials were extracted from different agricultural wastes such as corn stalks, olive solid waste, and wood, by using a suitable extraction method. The extracted cellulosic materials were characterized using Fourier transform infrared spectroscopy. The produced cellulosic materials were used as reinforcements for low-density polyethylene to improve its tensile and thermal properties. A two-roll mill was used to mix the cellulosic materials (2.5–10 wt.%) with low-density polyethylene , and then the composite sheets were prepared by using a thermal press molding. The effects of filler type and its content on the mechanical and thermal properties were investigated by using the universal testing machine and differential scanning calorimeter, respectively. In general, with the increase of cellulosic materials content, there is an increase in the modulus of elasticity of the produced composites and a decrease of ductility. The ultimate tensile strength of the produced composites based on low-density polyethylene and cellulosic materials extracted from corn stalks and olive solid waste was found to be less than the tensile strength of low-density polyethylene, whereas the ultimate tensile strength of the composites based on low-density polyethylene and cellulose powder extracted from wood increased with increasing the cellulosic content. The addition of cellulosic materials was found to affect both the melting temperature of low-density polyethylene and its degree of crystallinity, depending on the cellulosic material source.

2011 ◽  
Vol 18 (6) ◽  
pp. 2275-2284 ◽  
Author(s):  
Muhammad J. Khan ◽  
Abdulhadi A. Al-Juhani ◽  
Reyad Shawabkeh ◽  
Anwar Ul-Hamid ◽  
Ibnelwaleed A. Hussein

Author(s):  
Gurminder Singh ◽  
Pulak M Pandey

In the present paper, mechanical and thermal properties of rapidly manufactured copper parts were studied. The combination of three-dimensional printing and ultrasonic assisted pressureless sintering was used to fabricate copper parts. First, the ultimate tensile strength and thermal conductivity were compared between ultrasonic assisted and conventional pressureless sintered samples. The homogenously mixing of particles and local heat generation by ultrasonic vibrations promoted the sintering driving process and resulted in better mechanical and thermal properties. Furthermore, response surface methodology was adopted for the comprehensive study of the ultrasonic sintering parameters (sintering temperature, heating rate, and soaking time with ultrasonic vibrations) on ultimate tensile strength and thermal conductivity of the fabricated sample. Analysis of variance was performed to identify the significant factors and interactions. The image processing method was used to identify the surface porosity at different parameter levels to analyse the experimental results. High ultimate tensile strength was obtained at high sintering temperature, long soaking time, and slow heating rate with low surface porosity. After 60 min of soaking time, no significant effect was observed on the thermal conductivity of the fabricated sample. The significant interactions revealed less effect of soaking time at low sintering temperatures for ultimate tensile strength and less effect of heating rate at low sintering temperatures for thermal conductivity. Multi-objective optimization was carried out to identify parameters for maximum ultimate tensile strength and maximum thermal conductivity.


2017 ◽  
Vol 2017 ◽  
pp. 1-9
Author(s):  
Jong Won Kim ◽  
Joon Seok Lee

Polyethylene is one of the most commonly used polymer materials. Even though linear low density polyethylene (LLDPE) has better mechanical properties than other kinds of polyethylene, it is not used as a textile material because of its plastic behavior that is easy to break at the die during melt spinning. In this study, LLDPE fibers were successfully produced with a new approach using a dry-jet wet spinning and a heat drawing process. The fibers were filled with carbon nanotubes (CNTs) to improve the strength and reduce plastic deformation. The crystallinity, degree of orientation, mechanical properties (strength to yield, strength to break, elongation at break, and initial modulus), electrical conductivity, and thermal properties of LLDPE fibers were studied. The results show that the addition of CNTs improved the tensile strength and the degree of crystallinity. The heat drawing process resulted in a significant increase in the tensile strength and the orientation of the CNTs and polymer chains. In addition, this study demonstrates that the heat drawing process effectively decreases the plastic deformation of LLDPE.


Crystals ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 1520
Author(s):  
Salem Mohammed Aldosari ◽  
Sameer Rahatekar

Mesophase pitch-based carbon fibres have excellent resistance to plastic deformation (up to 840 GPa); however, they have very low strain to failure (0.3) and are considered brittle. Hence, the development of pitch fibre precursors able to be plastically deformed without fracture is important. We have previously, successfully developed pitch-based precursor fibres with high ductility (low brittleness) by blending pitch and linear low-density polyethylene. Here, we extend our research to study how the extrusion dwell time (0, 6, 8, and 10 min) affects the physical properties (microstructure) of blend fibres. Scanning electron microscopy of the microstructure showed that by increasing the extrusion dwell from 0 to 10 min the pitch and polyethylene components were more uniformly dispersed. The tensile strength, modulus of elasticity, and strain at failure for the extruded fibres for different dwell times were measured. Increased dwell time resulted in an increase in strain to failure but reduced the ultimate tensile strength. Thermogravimetric analysis was used to investigate if increased dwell time improved the thermal stability of the samples. This study presents a useful guide to help with the selection of mixes of linear low-density polyethylene/pitch blend, with an appropriate extrusion dwell time to help develop a new generation of potential precursors for pitch-based carbon fibres.


2019 ◽  
Vol 135 (5) ◽  
pp. 1042-1044 ◽  
Author(s):  
L. Altay ◽  
A. Guven ◽  
M. Atagur ◽  
T. Uysalman ◽  
G. Sevig Tantug ◽  
...  

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