Plastic fabrication shapes the modern world, transforming raw polymers into everything from disposable packaging to precision aerospace components. However, not all plastics are created equal. Commodity and engineering plastics are two common types of thermoplastics, which can be melted, reshaped, and solidified repeatedly. Commodity plastics are designed for cost-effective, high-volume production of everyday items, while engineering plastics offer superior performance for demanding applications. In this article, we will discuss the unique characteristics, main types, and applications of each.
What Are Commodity Plastics?
Commodity plastics are all around us in daily life— you can easily find them on your refrigerator or in your kitchen. According to Grand View Research, the global commodity plastics market was valued at USD 498.2 billion in 2024 and is projected to grow at a CAGR of 2.9% from 2025 to 2030. One of the most demanding markets is single-use products, including common items like cling film, plastic bags, beverage bottles, disposable tableware, and medical gloves. In addition to these, commodity plastics are widely used in other everyday consumer goods that require basic mechanical strength and thermal stability, such as children’s toys, electronics casings, and appliance housings. They are cost-effective and easy to process, therefore often produced in very high volumes.
There are many different types of commodity plastics, each with unique properties and applications. Below are some of the most common:
Polyethylene (PE)
It is reported that, Polyethylene (PE) is the most commonly used plastic, accounting for a big revenue share of 34.4% in 2024 across various industries. The demand for PE is mainly driven by its use in packaging, such as films, bags, and containers, due to its lightweight, chemical resistance, ease of processing, and recyclability.
In addition, with advancements, PE comes in several performance variants. Low-Density Polyethylene (LDPE) is softer and more transparent, making it well-suited for packaging films and plastic bags. High-Density Polyethylene (HDPE) is stronger and denser, commonly used for high-strength bottles and containers, or pipes, tanks, and components for underground drainage systems. Linear Low-Density Polyethylene (LLDPE) combines the flexibility of LDPE with the strength of HDPE, offering enhanced tear resistance and puncture resistance, and commonly found in agricultural films and covering materials.
Polypropylene (PP)
Polypropylene (PP) and polyethylene (PE) are both polyolefins. They have similar properties, such as good chemical resistance, low density, and low water absorption. But PP has better heat resistance, and is often chosen for items like microwave-safe containers, hot water pipes, and automotive engine covers.
PP is also more rigid and has better fatigue resistance. It is used in automotive interiors, industrial enclosures, and living hinges. Moreover, PP has higher transparency. In the medical field, it is used for syringes, IV bottles, pharmaceutical packaging, and disposable protective gear like surgical gowns and mask filter media.
Polyvinyl Chloride (PVC)
PVC is a long-established commodity plastic with a low cost. It has chlorine in its molecular chain, which gives it some flame-retardant properties. This is important for fire-resistant applications in the electrical and construction industries. PVC is easy to process in various ways, including extrusion, injection molding, blow molding, and calendaring. It can also be modified by adding plasticizers, stabilizers, lubricants, fillers, and pigments to alter its properties.
PVC comes in two forms. Rigid PVC (uPVC) contains little to no plasticizer, which makes it hard, rigid, and impact-resistant. With the right stabilizers, it also has good weather resistance and UV stability. uPVC is commonly used in pipes, window frames, and credit cards. Plasticized or flexible PVC becomes softer by adding a higher amount of plasticizers. This lowers its glass transition temperature (Tg), making the material more flexible and easier to bend. Flexible PVC is often found in cable insulation, flooring, inflatable toys, and medical tubing. However, attention should be paid to the potential migration and evaporation of plasticizers, which could affect health and the environment.
Polystyrene (PS)
Polystyrene (PS) naturally appears as a highly transparent, glass-like solid. It is somewhat rigid but has low impact strength and can break easily. When blended or copolymerized with other polymers, such as by adding rubber, it becomes High Impact Polystyrene (HIPS), which offers improved impact strength and toughness. This form is widely used in household appliance casings, computers, toys, and signs.
PS is also available in foam forms, such as expanded polystyrene (EPS) or extruded polystyrene (XPS). These lightweight foams have excellent heat insulation, shock resistance, cushioning, and sound absorption. They find use in building insulation, protective packaging, and insulation boards. However, PS is not easily biodegradable, and the process of recycling and reusing waste is quite challenging.
What Are Engineering Plastics?
Unlike commodity plastics, which are economical and mass-produced for everyday items, engineering plastics are designed to withstand mechanical and environmental conditions that commodity plastics are not made to deal with. They are usually semi-crystalline, which means they have improved rigidity, strength, heat resistance, chemical stability, and sometimes even self-lubrication. However, they are more expensive and are typically produced in smaller quantities to meet specific business requirements or high-performance goals.
Although engineering plastics are less common than commodity plastics, their use is growing as they make inroads into applications that traditionally relied on metals or other materials. Therefore, it can still be challenging to select the right material for your machining project. However, you can use plastic prototyping options to make better choices. Next, let’s take a look at some common types of engineering plastics:
Polycarbonate (PC)
Polycarbonate (PC) has carbonate groups in its chemical structure, which form a stiff linkage between polymer chains and make the material stronger and more rigid. This is why PC is good for safety and impact-resistant products like bulletproof glass, helmets, and automotive windshields. The carbonate linkage also resists deformation at high temperatures, giving PC good dimensional stability.
As an amorphous engineering thermoplastic, polycarbonate has very low water absorption and high optical transparency, which makes it well-suited for optical lenses, eyeglass lenses, and LED light covers. Moreover, PC is easy to machine or mold into desired shapes. However, it is sensitive to ultraviolet light, long-term outdoor use may require additional UV stabilizers.
Polymethylmethacrylate (PMMA) / Acrylic
PMMA is one of the earliest engineering polymers in the acrylic family. Like PC, it is transparent but offers superior light transmission, often reaching up to 92%. This makes it a lightweight alternative to glass and widely used in light pipes, optical lenses, diffusers, skylights, and high-quality displays. However, PMMA’s relatively poor scratch resistance is a concern in high-visibility applications, such as windshields, where a clear surface is essential for safety. It is one of the hardest polymers and has good weather resistance , performing well in outdoor use. While PMMA is rigid and has good tensile strength, it can be brittle and may crack under high stress or impact if not properly designed.
Polyoxymethylene (POM) / Acetal
POM is a highly crystalline and linear thermoplastic that offers an excellent balance of strength, stiffness, and toughness.Its stiffness and strength, particularly in the temperature range 50 to 120°C, are greater than those of most other thermoplastics. At room temperature, POM shows a distinct yield point at around 8–10% elongation; below this point, it recovers elastically even after repeated stress, providing excellent spring capacity and suitability for snap fastenings.
In addition, POM has good wear resistance, a low dynamic friction coefficient, and favorable electrical properties. It is generally resistant to creep and most organic solvents. Its high heat distortion temperature allows it to perform well at elevated temperatures, while it remains effective at temperatures as low as –40°C.
The combination of these properties makes POM especially suitable for precision components such as watch parts, rollers, bearings, gearwheels, housing parts, pump parts, valves, and gears. Furthermore, the POM family is often reinforced with glass fiber to further enhance the mechanical properties of the base polymer.
Polyamide (PA) / Nylon
Polyamide (Nylon) is a versatile engineering plastic that is available in different ‘grades’ and applied accordingly. PA 6/6 has a high melting point, strong mechanical strength, and excellent wear resistance. It is used in parts that face repeated friction and stress, like gears, bearings, and fasteners. PA 6 offers better formability and flow at a lower cost. While its melting point and mechanical strength are slightly lower than PA 6/6, PA 6 is particularly effective at forming fibers. This makes it popular for textiles, carpets, clothing, and fishing nets, and everyday items like toothbrush bristles, ropes, and nylon bags.
Nylon resists oils and solvents to a certain extent but is not very resistant to acids and bases. It also absorbs moisture, which can affect its size and weaken some of its properties. In some cases, the humidity must be controlled or the material modified to ensure stable performance.
Polyetheretherketone (PEEK)
PEEK is an extremely high-performance plastic used in aerospace, automotive, medical, and food processing sectors. One of its key advantages is its ability to withstand high temperatures— up to around 250°C— which far exceeds the thermal limits of most common plastics. It also offers excellent tensile strength, stiffness, and resistance to wear and fatigue, while being highly resistant to nearly all chemicals. Additionally, PEEK has low moisture absorption and is biocompatible. However, it is more expensive than most CNC plastics due to high raw material costs and the complexity of its machining process.
Polyethylene Terephthalate (PET)
PET is a strong, transparent, semi-crystalline plastic with excellent chemical resistance. It is the primary material for polyester fibers used in clothing and home textiles. PET also provides outstanding barrier resistance to gases and moisture, helping keep beverages and perishable foods fresh by preventing oxygen and humidity from entering. Moreover, PET is widely recycled through a well-established closed-loop system, making it an attractive option for eco-friendly packaging.
Polybutylene Terephthalate (PBT)
PBT is similar in structure to PET but includes an extra –(CH₂)₂– group in its backbone. This longer aliphatic segment gives PBT improved mechanical strength, stiffness, lower moisture absorption, and better dimensional stability compared to PET. It also has excellent electrical insulation and chemical resistance. These properties make PBT popular for automotive, electrical, and industrial components such as connectors, gears, and precision parts where higher performance is required.
Polytetrafluoroethylene (PTFE)
PTFE has one of the lowest friction coefficients among solids. This means that components such as bearings, seals, and sliding parts made from PTFE typically do not require additional lubricants. Its naturally non-stick surface is also widely used in cookware coatings and other applications where adhesion is problematic. Additionally, PTFE is highly resistant to nearly all chemicals and offers excellent heat resistance, withstanding continuous exposure to temperatures up to 260°C (500°F). It also provides effective electrical insulation. However, compared to other engineering plastics like PEEK or POM, PTFE is relatively soft, has low tensile strength, and tends to deform under constant stress.
Conclusion
Commodity plastics are cost-effective materials with basic strength, thermal, and chemical properties. They are widely used in packaging, disposable products, household items, and everyday consumer goods. In contrast, engineering plastics offer excellent mechanical, chemical, electrical, and optical properties, and have become the preferred choice for replacing materials like metals and ceramics in demanding applications. If you have any further questions or product requirements regarding plastic materials, please feel free to contact us!
FAQ
1. What is the difference between engineering plastics and specialty plastics?
Engineering plastics are high-performance materials that offer high strength, heat resistance, and chemical stability for demanding applications. Common examples include PC, PMMA, and POM.
Specialty plastics are designed for specific,niche applications that require unique properties, such as extreme chemical resistance, outstanding optical clarity, specialized electrical properties, and exceptional environmental stability. Liquid Crystal Polymers (LCP), Polyetherimide (PEI), and high-performance thermosets like epoxy resins are the typical examples.
2. What is the strongest engineering plastic?
There isn’t a single “strongest” engineering plastic overall because strength depends on the specific property (tensile, flexural, impact, etc.) and the conditions of use. However, Polyamideimide (PAI) is regarded as having the highest tensile strength among unreinforced thermoplastics, reaching about 21,000 psi. This high-performance material also has excellent wear and radiation resistance, low flammability and smoke emission, and high thermal stability. PAI is widely used in jet engines, internal combustion engines, thrust washers, and printed circuit boards, as well as in valves, gears, bearings, electrical connectors, and other critical mechanical components.
3. What is the most widely used commodity plastic?
Polyethylene (PE) is the most widely used plastic, accounting for over 34.4% of total plastic production in 2024. It is a cost-effective thermoplastic polymer that is easy to mold, making it a staple in packaging, consumer products, and industrial applications. Its various forms, such as LDPE and HDPE, further expand its global use.
