Thermoplastic Materials

Thermoplastic materials are a very important part of engineering materials. They have a very wide range of application areas in engineering. There are lots of kinds of informative articles in Mechanicalland about thermoplastics materials. Thermoplastics are the class of polymer materials that can have melting capability, unlike thermosetting materials. Here, we will give detailed information and the types of different thermoplastic materials.

Most Common Thermoplastic Materials in Industry

This is a very important list where you can find the most important commercial thermoplastic materials.

Acetal Thermoplastics

Acetal is a very important thermoplastic material that has various kinds of applications in engineering and daily use. These application areas of acetals are because of their specific properties. Here, we give summary information about acetals.

Acetal has another name that is ‘polyoxymethylene’. They produce the source thermoplastics material that acetal from is ‘formaldehyde(CH2O)’. Acetal has very important mechanical characteristics and properties around other thermoplastic materials; Also, the High stiffness, toughness, strength and wear resistance properties of acetal make this material very important for such applications. Acetals have a high melting temperature compared with other thermoplastics. And it is insoluble in the open air with solvents.

Because of these competitive properties, they use acetal in such applications instead of metals such as automotive parts, door handles, etc. Because of its wear and corrosion resistance, we can use acetal materials used in pump housings.

Properties of Acetal;

• Modulus Of Elasticity Of Acetal: 3500MPa(507,630 lb/in2)
• Tensile Strength Of Acetal: 70 MPa(10,150 lb/in2)
• Symbol Of Acetal: POM
• Production Method Of Acetal: Step Polymerization
• Degree Of Crystallinity Of Acetal: Around 75%
• Elongation Of Acetal: 25-75%
• Glass Transition Temperature Of Acetal: -80C(-112F)
• Melting Temperature Of Acetal: 180C(356F)

Acrylics

The production of acrylics is made from acrylic acid(C3H4O2). In the acrylics group, PMMA which is an acronym for polymethylmethacrylate is the most important one. The transparency of acrylics makes them very competitive with glass. This is probably because of their amorphous and linear structure. As you know that amorphous molecular structure gives materials translucency and transparency. Also, some applications of acrylics because of this transparency; are aircraft window applications, optical instruments, and automotive. Also, we use acrylics as fibers in the textile application.

Properties of Acrylics;

• Modulus of elasticity of PMMA: 2800 MPa(406,110 lb/in2)
• Tensile strength of PMMA: 55 MPa(7975 lb/in2)
• Glass transition temperature(Tg) of PMMA: 105C(221F)
• Melting temperature of PMMA: 200C(392F)
• The production method of PMMA: Addition polymerization

ABS Thermoplastic Polymers

ABS also called acrylonitrile–butadiene–styrene is one of the most important polymers in thermoplastics because of its special properties. Here, we give information about ABS polymer properties and application areas.

As you understand from its name that ABS is the acronym for acrylonitrile–butadiene–styrene. The production of ABS polymer starts with three types of monomers which they stated in ABS’s name. So, this ‘terpolymer’ microstructure of ABS has two phases at the same time. The first phase is the rubbery phase which originated from the styrene-butadiene copolymer structure. And also, the second phase of ABS thermoplastic polymer has a hard and brittle structure that they originate from styrene–acrylonitrile. We can compose these starting monomers in various percentages to obtain different structures of ABS materials.

The main applications of ABS polymers; are automotive components, fitting and piping applications, and some engineering appliances.

Properties Of ABS;

ABS polymer is produced with addition polymerization. And ABS has an amorphous molecular structure and has no degree of crystallinity. The modulus elasticity of ABS polymer is around 2100MPa and tensile strength is around 50MPa. Elongation of ABS polymer changes between 30-70% according to its original shape.

Polytetrafluoreethylene(PTFE)

We call this material also ‘Teflon’ which we are more hearsay about it. Here, we give some information about polytetrafluorethylene and its applications and properties.

What is PTFE

If we take a look at the molecular structure of Teflon, we can see the replacement of H atoms with F atoms in polymer chains. And also, these long and not cross-linked molecular structure makes Teflon thermoplastic polymer. General properties of PTFE;

• Teflon is very resistant to temperature which makes Teflon a commonly used material in most cooking pans.
• Teflon is very resistant to chemical or environmental attacks and unaffected by water applications. This property makes Teflon the proper material for chemical and food applications.
• Furthermore, Teflon has a very low coefficient of friction which makes Teflon is very appropriate polymer product for non-lubricating bearings that we use in machinery.

Properties Of PTFE; 

The production method of Teflon is addition polymerization. Unlike most amorphous thermoplastics, Teflon has a 95% of crystalline structure in it. The modulus of elasticity of Teflon is around 450 MPa. The tensile strength of Teflon is around 20 MPa. Teflon is an elastic polymer that has an elongation ratio of 100-300% according to its original shape. The glass transition temperature of Teflon is around 127C and the melting temperature of Teflon is around 327C.

Polycarbonate(PC) Thermoplastic Polymers

Polycarbonates are renowned for their very good mechanical properties such as very good creep resistance and high toughness. In addition to these excellent mechanical properties, polycarbonate has the property of preserving its properties up to around 125C temperatures. Also, it is a very high application temperature around thermoplastics, even in all the polymers. Amorphous molecular structure gives polycarbonates a transparent property.

We can list the applications of polycarbonates as;

• Window and windshield application because of its transparency.
• We use polycarbonate in pump impellers because of its toughness.
• We can use polycarbonates as housings of dynamic parts for machinery.

Properties of Polycarbonates;

Polycarbonate has chemical expression of (C3H6(C6H4)2CO3)n, n means that each monomer group in polycarbonates. The production process of polycarbonates is step polymerization. It has an amorphous molecular structure that gives transparency to polycarbonates. Polycarbonate has a tensile strength of around 65MPa and modulus elasticity of 2500 MPa. Polycarbonate has a medium value of elasticity which elongates around 100% of its original shape. The complete melting temperature of polycarbonates is around 230C and the glass transition temperature is around 150C.

Polyester Thermoplastic Polymers

Polyesters are very important properties that provides used in different applications in engineering and daily applications. Polyesters constitute a very narrow class in thermoplastic polymers but their applications in daily life are very prominent. Here, we explained the properties of polyesters and their general applications of them.

What is Polyester?

As you understand from its name, polyesters are polymer structures with ester(CO-C) bonding in monomers. The most prominent example of thermoplastic polyesters is polyethylene terephthalate(PET). We said ‘for thermoplastics’ because also there is another group that we call thermosetting polyesters. A polyester polymer can be either thermoplastic or thermosetting according to its cross-linked molecular structure.

PET does not have any exact amorphous or crystalline structure, it depends on the cooling rate from the molten state. Rapid cooling gives a more amorphous structure. Also, deformation recovery and low moisture absorption properties of PET polymer are very important.

We can list the typical applications of PET listed as;

• They use PET polymers mostly for garments to prevent wrinkling because of their deformation characteristics. We produce PET as fibers to mix with cotton and wool in some percentages.
• As you know from daily life PET is used for beverage containers that we produce with blow-molding.
• Photographic films and magnetic recording tapes are also significant applications areas of PET.

Properties Of PET Polymer;

The chemical representation of PET is (C2H4–C8H4O4)n, n means the number of monomers. The production technique for PET is step polymerization in general. The degree of crystallinity of PET ranges from amorphous to 30% of crystallinity. The melting temperature of PET is around 265C and the glass transition temperature of PET is around 70C. PET has a very good elastic behavior according to average values in polymers, which has around 200% of elongation according to its original shape. The tensile strength of PET is 55 MPa and the modulus of elasticity of PET is 2300 MPa.

Propylene Plastics

Propylene constitutes a very important part of thermoplastics. Because of propylene’s specific properties over other thermoplastic materials, it finds very specific applications in engineering and industry. Here, we explained the general properties of propylenes and applications that we use polypropylene.

What is Propylene?

Injection molding is one of the most important plastic part production techniques. If a plastic material has a very good characteristic to produce parts by injection molding from it, it can be a very important material polymer realm. So propylene has a very good ability to process in injection molding. Propylene has an acronym that is ‘PP’. They produce propylene in isotactic, atactic, and syndiotactic structures. In general applications, the isotactic structure of propylene is the most important one. Propylene has very specific properties to use in such specific applications;

• Lightweight: Propylene is the most lightweight plastic in the polymer realm. Also, propylene has a very good strength-to-weight ratio which provides a very wide range of applications in engineering, where lightweight is important.
• High Melting Point: High melting point of propylene gives importance where sterilization of plastic materials is important. Sterilization is made at high temperatures and plastic like propylene must withstand these high temperatures.
• Fatigue Strength: Hinges that have no joints are made by propylenes generally. This is because the property of the fatigue strength of propylene gives physical property to withstand high cycles of load.

Also, propylenes properties are nearly the same as HDPE. They use propylenes also in lots of applications that the parts that we produce with injection molding.

Properties of Propylene;

The production method of propylene plastics is addition polymerization. The degree of crystallinity of propylene can be somewhat high, but it can change with the process. The elasticity of propylene also changes dramatically. The elongation of propylene is around 10-500%. The tensile strength of propylene is 35MPa and the modulus of elasticity is around 1400 MPa. The melting temperature of propylene is around 176C. The chemical representation of propylene is (C3H6)n. ‘n’ represents the monomer number in the propylene chain.

Polyamides

If we take a look at the chemical structure of the molecular structure of polyamides, these have amide bondings in long chains of polymer structures. The most important and known polyamide material is nylons. Nylons have two major groups according to the C atom number inside their monomers; nylon6 and nylon 6-6. The general properties of nylons are;

• Elastic behavior makes nylon a preferable polymer in most applications.
• Resistant to abrasive environments and self-lubrication characteristics.
• Nylons can retain their good mechanical properties up to 125C temperature, which is a very important property around other thermoplastic polymers.

We can list the general applications of nylons as;

• Production of fibers in carpets because of their elastic behavior.
• We use nylons in tire cords because of their elastic behavior and abrasion resistance.
• Low friction required areas or applications such as bearings gears in machinery.

Aramids(aromatic polymers) are a very important polymer group in polyamides. They are used as reinforced plastics which have the commercial name ‘Kevlar’. It shows mechanical strength as steels, but the weight of these aramids is around 20% of steels.

Properties of Nylon 6-6;

Nylon 6-6 has a symbol that PA6-6 and the production method of Nylon 6-6 is step polymerization. Glass transition temperature of Nylon6-6 is around 50C and the melting temperature is around 260C. Nylon 6-6 has a highly crystalline structure which gives its mechanical properties. Nylon6-6 has a modulus of elasticity value of 700 MPa and a tensile strength value of 70 MPa. Nylon6-6 has very good elastic behavior that has 300% of elongation according to its original shape.

PVC(Polyvinylchloride)

Polyvinylchloride, another name which is an acronym of it; PVC is one of the most common thermoplastic materials in the polymer market. PVC has very specific properties. Because of these properties, PVC finds very interesting application areas in engineering and daily life. Here, we explain the properties of PVC polymers and their applications of it because of these properties.

What are the Applications of PVC Thermoplastic Material?

Commercial PVC polymer has a wide range of physical and mechanical properties because of the additives that they mix with PVC. Generally, these physical and mechanical properties of PVC changed with the addition of plasticizers. Without plasticizers, we obtain much more brittle and hard PVC. With the addition of plasticizers, we obtain more ductile and elastic PVC. Because of the versatility of PVC, there are lots of application areas;

• For example, we use PVC in food packaging, films, and sheet production because of its ductile property with plasticizers.
• We use PVC again in the production of rigid pipes for sewer, irrigation, or construction. In these applications, the used PVC must be rigid and strong.

But PVC has a drawback in that can be degraded under sunlight. Heat and light affect PVC in a bad situation. To overcome this, we add some kinds of additives to improve the resistance to these conditions.

Properties of PVC

Properties of PVC

Polyvinylchloride has the chemical symbol of (C2H3Cl)n. ‘n’ means the number of monomers in the polymer chain. The production process of PVC is the addition polymerization. Because PVC is a carcinogenic material, we must take special care in the phase of production. Glass transition temperature of PVC is around 81C and the melting temperature of PVC is around 212C. In most brittle structures, PVC has an elongation ratio of 2% of its original shape. There is no degree of crystallinity in PVC because it has a fully amorphous structure. The tensile strength of PVC is 40 MPa and the modulus of elasticity of PVC is around 2800 MPa.

Polystyrene Polymer

Just like other thermoplastic materials, polystyrene has also very specific properties. Because of these specific properties, it finds various kinds of applications in engineering and daily life. Here, we explain the general properties of polystyrene and the applications that we use polystyrene hence these properties.

What is Polystyrene and What are the Applications?

Polystyrene is produced in the highest volume around different copolymer and terpolymer structures of styrene monomer(C8H8). But polystyrene has a linear molecular structure and an amorphous structure. Also, it has very brittle behavior which is a very interesting one. Because of this brittleness, 5-155 rubbery materials are added to polystyrene polymers. These polystyrenes are called high-impact polystyrene(HIPS). With the addition of these additives, the toughness of polystyrene increases, but transparency reduces. There are some important properties of polystyrene polymer;

• Polystyrene has a transparent structure because of its amorphous molecular alignment.
• Polystyrene can be used in blow molding because of its easily molded structure.
• Polystyrene is sensitive to high temperatures that it can degrade. Also, it is sensitive to solvents.
• Polystyrene parts can be colored very well.

Properties of Polystyrene; 

The symbol of polystyrenes is ‘PS’. It is spelled like that in chemistry. Addition polymerization is the production process of polystyrenes. Polystyrene polymer is fully amorphous and because of that, it has transparency. Because of its brittle nature, elongation of polystyrenes is very low, which is around 1%. The melting temperature of polystyrene is around 240C and the glass transition temperature is 100C which is somewhat high. The tensile strength of polystyrene is 50 MPa and the modulus of elasticity of polystyrene is around 3200 MPa.

Thermoplastic Polyethylene Polymers

Polyethylenes have the biggest market percentage in thermoplastic polymers. Several properties of these polymers make them the most common polymer material on market. Here, we give information about polyethylene polymers’ applications, properties and types.

The acronym for polyethylenes is PE and it has the biggest market in the polymer industry. Some of the properties of polyethylenes are; chemical inactivity, low cost compared with other thermoplastic polymers, and easy processing and production of them. Because of these properties, polyethylene constitutes the biggest market.

In general, there are two types of polyethylenes; low-density polyethylenes(LDPE) and high-density polyethylenes(HDPE). The main difference between LDPE and HPDE polymers is the molecular structure. LDPE polymers have branched molecular structure, and because of that, it s called low-density. But HDPE has a much more linear molecular structure and higher crystallinity ratio which give high-density properties to HDPE polymers.

Because of the difference in the molecular structure of these two polyethylene types, HDPE is much stiff and strong compared to LDPE. General applications of HDPE pipe production, bottles, and other houseware products such as the frame of windows.

General applications that LDPE polymer is used; are wire insulation, squeezable bottles, bags, sheets, films, etc.

Properties of LDPE And HDPE

Both LDPE and HDPE have the same chemical representations which is (C2H4)n. ‘n’ means the number of monomers in LDPE and HDPE structures. Both of these types of polyethylenes are produced with the addition polymerization method. The elasticity modulus of HPDE is much higher than which is 700 MPa for HDPE and 140 MPa for LDPE. The tensile strength of HDPE is twofold of LDPE, 30 MPa and 15 MPa respectively. In terms of the degree of crystallinity, HDPE is 92% and LDPE is 55%. Glass transition temperatures of HDPE and LDPE are nearly the same, -115C and -100C respectively. Melting temperatures are very close to each other that is 135C for HDPE and 115C for LDPE. The elongation characteristics of LDPE are much higher than HDPE, which is 100-500% of the original shape for LDPE and 20-100% for HDPE.

Cellulosic Polymers as Thermoplastics

Nature is a very important source for the polymer production industry. Most polymers are also produced artificially. One of these nature-sourced thermoplastic polymers is cellulosic. Here, we explained the properties and applications of cellulosic polymers.

What is ‘Cellulosic Polymer’?

As you understand from its name, the natural source of cellulosic is Cellulose(C6H10O5). Also, there is no exact use of this natural polymer called Cellulose. The first process is applied to cellulose to obtain ‘regenerated cellulose’ is dissolving cellulose and reprecipitating it.

Cellulose can not be said of thermoplastic material, because they do not show thermoplastic behavior. Cellulose decomposes upon heating, in which melting for turning back is not possible. With some additives, thermoplastic polymers can be produced from cellulose. Cellulose-acetate(CA) and cellulose-acetate-butyrate(CAB) are the most important products that are produced in this way. CA is generally used to obtain film-like products. CAB shows better performance in molding. CA is superior to CAB in terms of strength to dynamic loadings, lower moisture absorption, and use of plasticizers.

Cellulose-sourced polymers can be used for apparel production and these types of cellulosic are called ‘rayon’. ‘Cellophane’ is another type of cellulosic that packaging materials are produced from it.

Properties of Cellulosics

The glass transition temperature of cellulosic is around 105C and the exact melting temperature of cellulosic is around 305C. The production process of cellulosic is generally stepped polymerization. Cellulosics are generally amorphous polymers and have no degree of crystallinity. Elongation of cellulosic ranges between 10-50% Modulus of elasticity of cellulosic around 2800 MPa and tensile strength of cellulosic is around 30 MPa.

Degradation of Thermoplastics Over Recycling

Thermoplastics are the sub-group of polymers. Thermoplastics have distinctive properties around other polymers and because of these properties, they constitute a specific class of polymers. Here, we explain a characteristic of thermoplastic polymers; degradation.

In the most basic explanation, thermoplastics’ most distinct property is; when heated to the liquid state, they can be cooled to a solid state. This cycle is available for thermoplastics. But for thermosetting which is the other class of polymers, there is no situation of melting. They burned when they were heated to elevated temperatures.

Cross-linking molecular structure leads to the situation of thermosetting. But there is no cross-linking molecular structure occurs for thermoplastics, when they heated up to elevated temperatures. Thermoplastics have the linear or branched type of molecules that leads to a cycle of heating or cooling property.

But in reality, there is a term for ‘thermal aging’ for thermoplastics. Thermoplastics degrade gradually with these thermal cycles. As you know, they prouce lots of scratches from thermoplastic polymer processes. We can use these scratches in other processes, but we are not considering them as ‘virgin’ material, which refers to the material’s first process. Because of this degradation of thermoplastics, quality decreases. In some applications, we require virgin thermoplastics. But for lots of other processes, we can use recycled thermoplastics.

So in theory, we can recycle the thermoplastics. But in reality, there is a rate of degradation for thermoplastics that we recycle.

Conclusion on Thermoplastic Materials

These are the most known and used thermoplastics on a commercial basis. And thermoplastic materials are a very important class of polymers.

There are different types of thermoplastic materials available in the market. So, it is very important to know their general properties of them.

Finally, do not forget to leave your comments and questions below about the thermoplastic materials.

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FAQs About Thermoplastics