Related Experiment Video
Updated: Nov 27, 2025
05:20
Characterization of Thermal Transport in One-dimensional Solid Materials
Published on: January 26, 2014
18.9K
Thermally Conductive Polyethylene/Expanded Graphite Composites as Heat Transfer Surface: Mechanical, Thermo-Physical
Patrik Sobolčiak1, Asma Abdulgader1, Miroslav Mrlik2
1Center for Advanced Materials, Qatar University, P.O. Box 2713 Doha, Qatar.
Polymers
|December 3, 2020
Summary
High-density polyethylene (HDPE) and expanded graphite (EG) composites show enhanced thermal conductivity and surface wettability for desalination heat exchangers. Plasma treatment improves performance and fouling resistance, approaching stainless steel efficiency.
Area of Science:
- Materials Science
- Chemical Engineering
- Polymer Science
Background:
- Desalination technologies require efficient and durable heat exchangers.
- High-density polyethylene (HDPE) composites offer potential but require property enhancement.
- Expanded graphite (EG) can improve thermal conductivity in polymer composites.
Purpose of the Study:
- To develop and characterize HDPE/EG composites for multi-effect distillation (MED) desalination heat exchangers.
- To investigate the effect of EG loading and plasma treatment on composite properties.
- To evaluate the performance and fouling resistance of the developed composites.
Main Methods:
- Preparation of HDPE/EG composites with varying EG content.
- Characterization of thermal conductivity, surface wettability (surface free energy), and viscoelastic properties.
- Application of corona and radio frequency (RF) plasma treatments.
- Assessment of overall heat transfer coefficient and crystallization fouling resistance.
Main Results:
- A 372% increase in thermal conductivity was achieved at 50 wt.% EG loading.
- Plasma treatment significantly enhanced surface wettability and retained it over two months.
- Processing techniques (extrusion vs. injection molding) were optimized based on EG content (below/above 30 wt.%).
- Plasma-treated composites achieved 98% of stainless steel's heat transfer coefficient and showed superior fouling resistance.
Conclusions:
- HDPE/EG composites are promising materials for desalination heat exchangers.
- Plasma treatment effectively enhances surface properties and fouling resistance.
- Optimized composite formulations and processing methods are crucial for efficient heat exchange applications.
Related Concept Videos
01:27Thermal expansion and Thermal stress: Problem Solving
1.9K
San Francisco's Golden Gate Bridge is exposed to temperatures ranging from -15 °C to 40 °C. At its coldest, the main span of the bridge is 1275 m long. Assuming that the bridge is made entirely of steel, what is the change in its length between these temperatures?
To solve the problem, first, identify the known and unknown quantities. The initial length (L) of the bridge is 1275 m, the coefficient of linear expansion (α) for steel is 12 x 10-6/°C, and the change in temperature (ΔT) is 55...
To solve the problem, first, identify the known and unknown quantities. The initial length (L) of the bridge is 1275 m, the coefficient of linear expansion (α) for steel is 12 x 10-6/°C, and the change in temperature (ΔT) is 55...
1.9K
01:14Mechanisms of Heat Transfer
1.2K
Heat transfer between the human body and its environment occurs through four main mechanisms: conduction, convection, radiation, and evaporation.
Conduction, accounting for approximately 3% of body heat loss at rest, is the process of exchanging heat between molecules of two materials in direct contact. This can result in both heat loss and gain. For instance, when the body is submerged in water, which conducts heat 20 times more effectively than air, it can either lose or gain significant...
Conduction, accounting for approximately 3% of body heat loss at rest, is the process of exchanging heat between molecules of two materials in direct contact. This can result in both heat loss and gain. For instance, when the body is submerged in water, which conducts heat 20 times more effectively than air, it can either lose or gain significant...
1.2K
01:20Mechanisms of Heat Transfer II
4.0K
In convection, thermal energy is carried by the large-scale flow of matter. Ocean currents and large-scale atmospheric circulation, which result from the buoyancy of warm air and water, transfer hot air from the tropics toward the poles and cold air from the poles toward the tropics. The Earth’s rotation interacts with those flows, causing the observed eastward flow of air in the temperate zones. Convection dominates heat transfer by air, and the amount of available space for the airflow...
4.0K
01:14Mechanisms of Heat Transfer I
5.4K
Just as interesting as the effects of heat transfer on a system are the methods by which the heat transfer occur. Whenever there is a temperature difference, heat transfer occurs. It may occur rapidly, such as through a cooking pan, or slowly, such as through the walls of a picnic ice box. So many processes involve heat transfer that it is hard to imagine a situation where no heat transfer occurs. Yet, every heat transfer takes place by only three methods: conduction, convection, and radiation.
5.4K
01:19Mechanism of heat transfer
1.7K
Understanding heat transfer mechanisms is essential for understanding how our bodies maintain balance in different environmental conditions. When the environment is thermoneutral, the body is in a state of balance, neither using nor releasing energy to maintain its core temperature. However, when the environment is not thermoneutral, the body employs four heat transfer mechanisms to maintain homeostasis: conduction, convection, evaporation, and radiation. These mechanisms facilitate heat...
1.7K
01:09Thermal Stress
3.1K
If the temperature of an object is changed while it is prevented from expanding or contracting, the object is subjected to stress. The stress is compressive if the object expands in the absence of constraint and tensile if it contracts. This stress resulting from temperature change is known as thermal stress. It can be quite large and can cause damage. To avoid this stress, engineers may design components so they can expand and contract freely. For instance, on highways, gaps are deliberately...
3.1K