Polystyrene vs. Polyethylene — What's the Difference?
By Maham Liaqat & Urooj Arif — Updated on May 3, 2024
Polystyrene is a rigid, brittle plastic used in products like foam cups and insulation, while polyethylene is flexible, used in bags and containers, and is known for its durability.
Difference Between Polystyrene and Polyethylene
Table of Contents
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Key Differences
Polystyrene is manufactured from styrene monomers and is often used for its rigidity and insulating properties, making it ideal for products like disposable coffee cups and packaging material. Polyethylene, on the other hand, is derived from ethylene and is valued for its flexibility and toughness, commonly used in shopping bags and milk jugs.
Polystyrene comes in several forms, including expanded polystyrene (EPS) and high-impact polystyrene (HIPS), each offering different levels of rigidity and impact resistance. Polyethylene also varies, with high-density polyethylene (HDPE) and low-density polyethylene (LDPE) providing options for higher rigidity or more flexibility, respectively.
In terms of environmental impact, polystyrene is less favorable due to its difficulty in recycling and its tendency to break down into microplastics. Polyethylene, while also a challenge in terms of environmental sustainability, is more commonly recycled and does not break down as easily into microplastics.
Polystyrene is generally less resistant to chemicals and UV light, leading to its degradation in various environments. Polyethylene exhibits better resistance to chemicals and is more durable under exposure to sunlight and weathering.
In the context of thermal resistance, polystyrene offers superior insulation properties, which is why it's often used in building insulation and refrigeration applications. Polyethylene, while not as effective an insulator, performs better in applications requiring durability against physical impacts.
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Comparison Chart
Base Monomer
Styrene
Ethylene
Typical Uses
Insulation, disposable cups, packaging
Plastic bags, containers, water pipes
Forms
EPS, HIPS
HDPE, LDPE
Environmental Impact
Difficult to recycle, forms microplastics
More commonly recycled, less microplastic formation
Chemical Resistance
Low
High
UV and Thermal Resistance
Low UV resistance, high thermal insulation
Higher UV resistance, lower thermal insulation
Compare with Definitions
Polystyrene
Susceptible to degradation from sunlight and certain chemicals.
Polystyrene products can degrade when exposed to UV light, limiting their outdoor use.
Polyethylene
HDPE form is known for its strength and density.
High-density polyethylene is used for making rigid plastic bottles like those used for milk or detergents.
Polystyrene
Known for its rigidity and brittle nature in its unexpanded form.
Polystyrene cases are commonly used for packaging electronics to prevent damage during shipping.
Polyethylene
A polymer made from the polymerization of ethylene, used in various forms.
Polyethylene is the most common plastic used globally, particularly in packaging.
Polystyrene
Difficult to recycle, contributing to environmental pollution.
Due to its composition, polystyrene is often not accepted in municipal recycling programs.
Polyethylene
Resistant to chemicals and moisture.
Polyethylene's chemical resistance makes it suitable for use in containers holding everything from household cleaners to juice.
Polystyrene
A synthetic aromatic hydrocarbon polymer made from the monomer styrene.
Polystyrene is often used to make disposable styrofoam drinking cups.
Polyethylene
Known for its toughness and flexibility, especially in LDPE form.
The flexibility of polyethylene makes it ideal for use in grocery bags and squeeze bottles.
Polystyrene
Available in foam form as expanded polystyrene (EPS).
Expanded polystyrene is used extensively in building for thermal insulation.
Polyethylene
More environmentally friendly in terms of recyclability compared to many plastics.
Polyethylene can often be recycled into new plastic products, reducing its environmental footprint.
Polystyrene
Polystyrene (PS) is a synthetic aromatic hydrocarbon polymer made from the monomer known as styrene. Polystyrene can be solid or foamed.
Polyethylene
Polyethylene or polythene (abbreviated PE; IUPAC name polyethene or poly(methylene)) is the most common plastic in use today. It is a polymer, primarily used for packaging (plastic bags, plastic films, geomembranes and containers including bottles, etc.).
Polystyrene
A rigid clear thermoplastic polymer of styrene that can be molded into objects or made into a foam that is used as thermal insulation.
Polyethylene
A polymerized thermoplastic ethylene resin, used especially for containers, kitchenware, and tubing, or in the form of films and sheets for packaging.
Polystyrene
(organic chemistry) A vinylic polymer of styrene, CH2CHphenyl.
Polyethylene
(organic compound) A polymer consisting of many ethylene monomers bonded together; used for kitchenware, containers etc.
Polystyrene
(organic chemistry) An alkane chain of benzene molecules, RCH2CHphenylR.
Polyethylene
A lightweight thermoplastic; used especially in packaging and insulation
Polystyrene
A polymer of styrene; a rigid transparent thermoplastic;
Expanded polystyrene looks like a rigid white foam and is used as packing or insulation
Common Curiosities
How are polystyrene and polyethylene used in packaging?
Polystyrene is used for rigid packaging and insulating properties, while polyethylene is used for flexible packaging like plastic bags.
What are the key physical properties of polystyrene and polyethylene?
Polystyrene is rigid and brittle, while polyethylene is flexible and tough.
What are the environmental impacts of using polystyrene vs. polyethylene?
Polystyrene is less recyclable and more likely to contribute to microplastic pollution than polyethylene.
Which is more chemically resistant, polystyrene or polyethylene?
Polyethylene has better chemical resistance than polystyrene, making it suitable for a wider range of chemical storage applications.
What are the most common forms of polyethylene and their uses?
HDPE is used for more rigid products like bottles, while LDPE is used for flexible items like plastic films.
Can polystyrene and polyethylene be recycled?
Polyethylene is generally easier to recycle compared to polystyrene, which is often not accepted in standard recycling programs.
Why is polystyrene often used in food packaging?
Its insulating properties make polystyrene ideal for keeping food temperatures stable.
How does the production of polystyrene and polyethylene affect their market cost?
Polystyrene is generally cheaper to produce, though polyethylene's versatility can offer better cost efficiency in varied applications.
Which material is better for outdoor applications?
Polyethylene, due to its UV resistance and durability.
What is the difference in UV resistance between polystyrene and polyethylene?
Polyethylene is more UV resistant than polystyrene, which can degrade under sunlight.
How do the insulation properties compare between polystyrene and polyethylene?
Polystyrene is a better insulator, commonly used in construction and refrigeration.
What are the durability differences between polystyrene and polyethylene?
Polyethylene tends to be more durable and less brittle than polystyrene.
What innovations are being developed to improve the recyclability of polystyrene and polyethylene?
Advances include chemical recycling techniques that break polymers back into monomers.
What future trends are expected in the use of polystyrene and polyethylene?
Environmental concerns and recycling technology are likely to influence future usage and disposal practices.
How do polystyrene and polyethylene affect the food industry?
Polystyrene is prevalent in disposable food packaging, while polyethylene is used in flexible food storage solutions.
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Written by
Maham Liaqat
Co-written by
Urooj ArifUrooj is a skilled content writer at Ask Difference, known for her exceptional ability to simplify complex topics into engaging and informative content. With a passion for research and a flair for clear, concise writing, she consistently delivers articles that resonate with our diverse audience.
