Polyethylene terephthalate, commonly abbreviated PET, PETE, is the most common thermoplastic polymer resin in the polyester family and is used in fibers for clothing, liquid packaging, and food. Polyethylene terephthalate polyester is a hard, rigid, strong and dimensionally stable material that absorbs very little water.
|phase in STP||solid|
|Tensile strength||150 MPa|
|stretch limit||40 MPa|
|Young's modulus of elasticity||9 GPa|
|brinell hardness||20 BHN|
|thermal conductivity||0,3 W/mK|
|heat capacity||1250 J/g K|
Typical densities of various substances are at atmospheric pressure.densityis defined asmass per unit volume. It is aintense ownership, which is defined mathematically as the mass divided by the volume:r = m/V
In words, the density (ρ) of a substance is the total mass (m) of that substance divided by the total volume (V) that that substance occupies. The standard SI unit iskilograms per cubic meter(kg/m33). The default unit for English ispounds of mass per cubic foot(lbm/pie3).
The density of PET is1350kg/m3.
Calculate the height of a PET cube that weighs one ton.
densityis defined asmass per unit volume. It is defined mathematically as the mass divided by the volume:r = m/V
Since the volume of a cube is the cube of its sides (V = a3), the height of this cube can be calculated:
So the height of this cube isa = 0,91m.
PET mechanical properties
In the mechanics of materials.strength of a materialIt is its ability to withstand an applied load without failing or plastically deforming.material thicknessfundamentally considers the relationship betweenexternal loadsapplied to and resulting from a materialdeformationor change in material dimensions. When designing structures and machines, it is important to take these factors into account so that the selected material has sufficient strength to withstand the applied stress or force and retain its original shape.
strength of a materialis its ability to withstand this applied load without failing or plastically deforming. In tension, the ability of a material or structure to support loads that tend to stretch is known as ultimate tensile strength (UTS).stretch limitor elastic limit is the material property defined as the stress at which a material begins to plastically deform, while the elastic limit is the point at which non-linear deformation (elastic + plastic) begins. When a uniform bar is subjected to tensile stress (stress-strain curve), theHooke's Lawdescribes the behavior of a bar in the elastic band. HeYoung's modulus of elasticityis the modulus of elasticity for tensile and compressive stress in the linear yield range of a uniaxial strain and is usually determined by tensile tests.
See too:material thickness
Maximum tensile strength of PET
The maximum tensile strength of PET is 150 MPa.
PET elastic limit
PET elastic limitis 40 MPa.
PET elasticity modulus
The elastic modulus of PET is 9 GPa.
in materials sciencetoughnessis the ability to bearshallow indentation(localized plastic deformation) YScratch.brinell hardness testis one of the indentation hardness tests developed for hardness testing. In Brinell tests, a resistant,ball indenteris pressed under a certain load onto the surface of the metal to be tested.
HeBrinell hardness number(HB) is the head divided by the area of depression. The diameter of the impression is measured using a microscope with a scale applied. The Brinell hardness number is calculated from the equation:
The Brinell hardness of PET is about 20 BHN (converted).
See too:material hardness
Let's assume a plastic rod made of PET. This plastic rod has a cross-sectional area of 1 cm.2. Calculate the tensile strength required to achieve the maximum tensile strength of this material: UTS = 150 MPa.
stress (σ)can be equated to the load per unit area or the force (F) exerted per cross-sectional area (A) perpendicular to the force as:
Therefore, the tensile force required to achieve the ultimate tensile strength is:
F= UTS x A = 150 x 106×0,0001 =15 000 norte
elasticity of materials
Thermal properties of PET
PET - melting point
The melting point of PET is 267C.
Note that these points are linked to standard atmospheric pressure. Generally,meltedit is aphase changepassage of a substance from the solid phase to the liquid phase. Hefusion pointof a substance is the temperature at which this phase change occurs. Hefusion pointit also defines a state where solid and liquid can exist in equilibrium. It is difficult to determine the melting point of many chemical compounds and alloys because they are mostly a mixture of different chemical elements.
PET - thermal conductivity
The thermal conductivity of PET is0,3 W/(m·K).
The heat transfer properties of a solid material are measured by a property calledthermal conductivity, k (or λ), measured inW/m.K. It is a measure of a substance's ability to transfer heat through a material.Management. keep in mind thatFourier leiIt applies to all matter, regardless of its state (solid, liquid or gaseous), so it is also defined for liquids and gases.
Hethermal conductivityof most liquids and solids varies with temperature. With vapors, pressure is also important. Generally:
Most materials are nearly homogeneous, so we can usually writek = k (T). Similar definitions apply to thermal conductivities in the y and z directions (ky, kz), but for an isotropic material, thermal conductivity is independent of the transfer direction, kx = ky = kz = k.
PET - specific heat
The specific heat of PET is1250 J/g K.
Specific heat or specific heat capacity,is a property related toinner energyThis is very important in thermodynamics. Heintense propertiesCvYCPAGare defined as partial derivatives of easily compressible pure substancesinner energytu(T,v)Yenthalpyh(T,p), or:
where the indicesvYPAGdenotes the variables that are registered during differencing. propertiesCvYCPAGare known asspecific heat(oCalorific Capacities) because they relate the temperature change of a system to the amount of energy added by heat transfer under certain particular conditions. Its SI units areJ/kg KoJ/mol K.
Example: Calculation of heat transfer
Thermal conductivity is defined as the amount of heat (in watts) that is transferred through a square area of material of a given thickness (in meters) due to a temperature difference. The lower the thermal conductivity of the material, the greater the material's ability to resist heat transfer.
calculate the rateheat fluxthrough a wall with an area of 3 m x 10 m (A = 30 m).2). The wall is 15 cm thick (L1) and consists of PET with thethermal conductivitybecause1= 0.3 W/m.K (poor thermal insulation). Embrace that, both indoors and outdoors.temperaturesare 22°C and -8°C, and theconvection heat transfer coefficientinside and outside are h1= 10 W/m2k e h2= 30 W/m2Answer K Note that these convection coefficients are highly dependent on environmental and indoor conditions (wind, humidity, etc.).
Calculate the heat flow (heat loss) through this wall.
As already written, many heat transfer processes are composite systems and even a combination of both.ManagementYConvection. With these composite systems, it is often convenient to work with aheat transfer coefficient,known as aThe U factor. The U factor is defined by an expression analogous tonewton's law of cooling:
Heheat transfer coefficientis related to thisoverall thermal resistanceand depends on the geometry of the problem.
Assuming one-dimensional heat transfer through the plane wall and disregarding radiation, theheat transfer coefficientcan be calculated as:
Heheat transfer coefficientis then: U = 1 / (1/10 + 0.15/0.3 + 1/30) = 1.58 W/m2k
The heat flux can be easily calculated as follows: q = 1.58 [W/m2K] x 30 [K] = 47,37 W/m2
The total heat loss through this wall is:qLoss= q. A = 47,37 [W/m2] x 30 [m2] =1421,05 W
melting point of materials
thermal conductivity of materials
heat capacity of materials
|Thermal Conductivity||0.190 - 0.290 W/m-K||1.32 - 2.01 BTU-in/hr-ft²-°F|
|Melting Point||200 - 260 °C||392 - 500 °F|
|Maximum Service Temperature, Air||60.0 - 225 °C||140 - 437 °F|
|Deflection Temperature at 0.46 MPa (66 psi)||66.0 - 250 °C||151 - 482 °F|
Thermoplastic materials become liquid at their melting point (roughly 260 degrees Celsius in the case of PET).What is the strength of PET material? ›
Some of PET's other physical and mechanical properties include: Tensile strength: 11,500 psi. Flexural modulus of elasticity: 400,000 psi. Tensile elongation: 70%What is the heat capacity of PET plastic? ›
|Polymer||Specific Heat (J/(kg oC))|
These resistances are referred to as Rsi and Rso respectively with common values 0.12Km²/W and 0.06Km²/W for the internal and external surfaces, respectively. This is the measure that is always within Building Regulations.What is the thermal conductivity of PET foam? ›
Excellent thermal insulation
Reaches excellent insulation values; up to 0.030 W/mK (thermal conductivity) R-value up to 1.67 m2K/W for 50 mm (2“) thickness.
The melting point of PET is approximately 260°C (500°F) which is considered high compared to other thermoplastics.Why does PET have a high melting point? ›
The strength of bonding in PET is higher than PBT. Also, it is more rigid than PBT. Therefore, PET has a higher value of the melting point.Is PET a good thermal insulator? ›
Although PET has excellent optical properties, weather resistance, and chemical resistance, its relatively weak insulation properties restrict its application in engineering plastic.What is 100% PET material? ›
Polyethylene terephthalate, also called PET, is the name of a type of clear, strong, lightweight and 100% recyclable plastic. Unlike other types of plastic, PET plastic is not single-use -- it is 100% recyclable, versatile, and made to be remade.
Polyesters (PET) have found their use as antistatic and electro-conductive materials.What are the weaknesses of PET plastic? ›
|The polymers are easily available and inexpensive||Lower heat resistance|
|High strength to weight ratio||PET resins are susceptible to oxidation|
|Highly transparent and shatterproof||Partially derived from crude oils|
|Easily Recycled||Not biodegradable|
PET has a glass transition temperature of 67–81°C and melting point of 260°C. It is commonly used in industrial applications due to excellent moisture and fair oxygen barrier characteristics.What is the difference between PET and plastic? ›
Is PET safer than other types of plastic? As previously mentioned, PET is shatterproof and will not cause harm if broken or damaged — it's known as the 'safe' plastic. PET doesn't contain Bisphenol-A (BPA) either, a chemical that can be harmful in large quantities.What is minimum thermal conductivity? ›
The concept of a minimum thermal conductivity, кmin, carried by the atomic vibrations of any solid material (crystalline or amorphous), is of practical technological importance.What is considered high thermal conductivity? ›
Which Metals Conduct Heat The Best? As you can see, out of the more common metals, copper and aluminum have the highest thermal conductivity while steel and bronze have the lowest.What is considered low thermal conductivity? ›
Steel features the lowest thermal conductivity and as such it is a great option for applications in high-temperature environments. As the lowest thermal conductivity metal, steel has about 45 W/mK. This is much lower than other metals like aluminum and copper which has about 235 W/mK and 398 W/mK respectively.What is a PET insulator? ›
Polyester insulation is made of Polyethylene Terephthalate (PET). This is a fibre commonly used in many household products like clothes and mattresses. PET is made of up to 85% recycled materials, sourced from things like plastic bottles, plastic bags, and other types of packaging.What is the thermal diffusivity of a PET? ›
For a PET sample, the heat diffusivity D is 0.093┬10└6 m2/s .What is the glass transition temperature of PET? ›
A literature survey for PET's glass transition temperature shows it to be between 69°C and 85°C, depending on the grade examined. Thermomechanical Analysis (TMA) compliant with ASTM E831 can be used to observe this behavior.
PET has a glass transition temperature of 67–81 °C and a melting point of 260 °C.What is low melt PET? ›
Low-melt polyester fiber refers to fiber with a melting point from 90 degrees to 220 degrees. 110℃ LMF is the most common in the market. When heated to 110-150 ℃, the sheath layer can melt and generate a sheath-core or side-by-side structure. It can be mixed with other fibers or be used alone.At what temperature does PET become malleable? ›
PET is a semi-crystalline thermoplastic, which softens at approx. 76°C (what is called “Glass Transition”). Above this temperature, the material becomes elastic, and can be formed, a property utilized effectively in the Stretch Blow Molding process.What does it mean to have a higher melting point? ›
A higher melting point indicates greater intermolecular forces and therefore less vapour pressure. Melting point test is not required for every chemical. Usually it is conducted for solid materials under normal conditions.What does it mean to have the highest melting point? ›
High melting point of a substance means that there will be more heat required to melt a particular substance from solid to liquid state. There are many elements that have high melting point.Example: for metals, we can say , more than 700° could be considered high melting point.What does a high melting point range mean? ›
A high melting point results from a high heat of fusion, a low entropy of fusion, or a combination of both. In highly symmetrical molecules the crystal phase is densely packed with many efficient intermolecular interactions resulting in a higher enthalpy change on melting.What is the best insulation for thermal conductivity? ›
Aerogel Insulation Technology
Classed as a Super Insulation, Aerogel has the highest insulation value of any known material with the lowest thermal conductivity value of any solid (0.015W/mK).
Unlike metals, plastics do not have free electrons available for conduction mechanisms. Hence, they are poor conductors of heat.What insulation has the best thermal conductivity? ›
1 Polyurethane foam. One of the best commercially available choices of insulation material for fishing vessels is polyurethane foam. It has good thermal insulating properties, low moisture-vapour permeability, high resistance to water absorption, relatively high mechanical strength and low density.Is PET stronger than HDPE? ›
HDPE is slightly more resistant to impact than PET and provides greater temperature resistance and a very good water vapor barrier. PET, however, is lighter, more versatile in its appearance, and more resistant to chemicals that might negatively affect other plastics.
PET, or polyethylene terephthalate, is the chemical name for polyester. When PET is used for fiber or fabric applications, it is usually referred to as “polyester.” When used for container and packaging applications, it is typically called “PET” or “PET resin.”What does PET 1 mean plastic? ›
#1 plastic: Polyethylene Terephthalate
Plastic number 1 refers to polyethylene terephthalate which is one of the most generally used thermoplastic polymer resin. We know it as PETE or PET plastic.
Polyesters (PET) have found their use as antistatic and electro-conductive materials. An increase in electric conductance of polyesters has been obtained to provide an effective dissipation of electrostatic charges and reduce electrostatic discharges.Is PET a good material? ›
Due to its good creep resistance as well as its low moisture absorption and excellent dimensional stability, PET plastic is ideal for use in complex parts with the highest demands on dimensional accuracy and surface quality. PET is also food safe.What is the electrical conductivity of PET? ›
A high electrical conductivity of 2.11S/m was achieved with only 3.0vol. % of graphene. The low percolation threshold and superior electrical conductivity are attributed to the high aspect ratio, large specific surface area and uniform dispersion of the graphene nanosheets in PET matrix.Why is PET plastic a problem? ›
Because PET doesn't readily break down, it contributes to plastic pollution. Plastics like PET can break down into tiny pieces called microplastics, which are pervasive in our oceans – as well as our bays, lakes, and even drinking water.Why is PET the best plastic? ›
PET is considered one of the best materials for plastic bottles because it is strong with little production cost and lightweight. Usually, the suitability of a storage or packaging material is decided based on how it compares with glass, metal, and wood which are considered friendly to the environment.Why is PET plastic better? ›
PET plastic is a safe and hygienic packaging solution. PET's composition means it doesn't react with food or liquids that come in contact. It's resistant to attacks from microorganisms making it a stable and risk-free material. PET is approved by health and safety boards.What happens when PET is heated? ›
When heated together under the influence of chemical catalysts, ethylene glycol and terephthalic acid produce PET in the form of a molten, viscous mass that can be spun directly to fibres or solidified for later processing as a plastic.What are the properties of PET plastic? ›
- High strength.
- High rigidity and hardness.
- Very low moisture absorption.
- Good creep resistance.
- Low sliding friction and sliding wear.
- Resistant to hydrolysis (up to +70 °C)
- Not suitable for contact with media containing >50% alcohol.
- Good chemical resistance against acids.
However, they exhibit a range of melting points depending on the route by which they were manufactured. Of the Big Six, polyethylene has the lowest melting point, with LDPE and HDPE melting at about 120 °C and 130 °C, respectively. In contrast, polypropylene (PP) melts at 160–170 °C.What's the difference between PET and HDPE? ›
HDPE is a very stiff, high-density plastic with a good temperature resistance and an excellent water vapour barrier. PET plastics are highly transparent in appearance, available in different colours, lightweight and tough against gases and liquids. PET is also highly resistant to diluted acids, oils and alcohols.Why is PET better than PVC? ›
PET is more expensive than PVC but, unlike PVC, it is environmentally friendly. PET is 100 per 100 recyclable, does not lose its fundamental properties during the recovery process and can therefore be transformed repeatedly to produce fine products.Which is better PVC or PET? ›
Safer for storing materials, especially food—PET plastic is highly suitable for packaging food items, as well as retail, electronic and other products. Increased durability —PVC is a rigid plastic that has some durability.What is the thermal conductivity of propylene glycol? ›
|Fluid||Thermal Conductivity (W/m K)|
|Sulfuric acid concentrated||0.5|
For most of thermoplastics, the TC at 25°C falls in the range of 0.11 W/mK (for polypropylene) and 0.44 W/mK (for high density polyethylene) .What is the thermal conductivity of PP fiber? ›
The test results showed that thermal conductivity (λ) is in a range between 0.19-0.82 W/m.C while the thermal conductivity is less than 1 W/m.C. This indicates that the geopolymer can be applied for thermal insulating material.What is the thermal conductivity of polyethylene insulation? ›
The thermal conductivity of Polyethylene is 0.4 W/m per ˚C.What liquid has highest thermal conductivity? ›
Water. Water is one of the best choices for liquid cooling applications due to its high heat capacity and thermal conductivity. It is also compatible with copper, which is one of the best heat transfer materials to use for your fluid path.Which substance has highest thermal conductivity? ›
Carbon has highest thermal conductivity of any known substance.
|Thermal conductivity||3000 W m−1K−1 (theoretical)|
|Magnetic susceptibility||22 × 106 EMU/g (perpendicular to plane)) 0.5 × 106 EMU/g (parallel to plane)|
|Thermal expansion||2 ×10−5 K−1 (SWCNT)|
|Thermal stability||300°C–600°C (CVD MWNT)) 600°C–800°C (arc-grown MWNT)|
A very high thermal conductivity (> 350 Wm-1K-1), even a divergent one, is possible for a single polyethylene chain2.What is the thermal conductivity of polymers? ›
The thermal conductivity of bulk polymers is usually very low, on the order of 0.1–0.5 W·m−1 K−1, which is due to the complex morphology of polymer chains .What are the thermal properties of PP material? ›
Polypropylene fibers have a softening point in the region of 150°C and a melting point at 160-170°C. At low temperatures of -70°C or lower, PP fibers remain their excellent flexibility. At high temperature (below 120°C). PP fibers nearly remain their normal mechanical properties.
p A 3-layer polyproylene applied to pipe surface has a conductivity of 0.13 BTU/hr-ft-8oF, while a 4-layer polypropylene has a conductivity of 0.10 BTU/hr-ft-8F.What is the thermal conductivity of high density plastic? ›
The thermal conductivity of HDPE is about 0.5 W/mK at 23°C, while that of PLA, ABS, and PP is 0.2 W/mK, and PA is 0.3 W/mK .How do you measure thermal conductivity of polymers? ›
Thermal Conductivity (W/mK)
Measurement results using the MTPS method on an anisotropic sample. C-Therm's FLEX TPS (ISO 22007-2 Hot Disc) method also offers the ability to measure the thermal conductivity of anisotropic materials, however with some notable differences compared to the MTPS.
The best insulator in the world right now is most probably aerogel, with silica aerogels having thermal conductivities of less than 0.03 W/m*K in atmosphere. of aerogel preventing ice from melting on a hot plate at 80 degrees Celsius! Aerogel has its amazing properties because it's mostly made out of air.