Polypropylene and polystyrene are two types of commonly used polymers in the manufacture of plastic laboratory consumables. Polymers are large molecules that have the same structural unit repeating over and over. The repeating units are called monomers. Polypropylene and polystyrene are both similar in many applications, but there are some inherent differences between them that make them more appropriate for specific applications.
Polypropylene
Polypropylene, also known as PP, is a thermoplastic polymer. It is commonly used to manufacture plastic laboratory supplies like beakers, bottles, flasks, specimen containers, test tubes, and many others. Polypropylene is exceptionally tough, unbreakable, flexible and resistant to many chemicals, acids, and bases. It also has a high level of heat resistance. Depending on the grade, polypropylene has a melting point of 130 °C (266 °F) up to 171 °C (340 °F). Many polypropylene products are autoclavable due to this high level of heat resistance. In contrast with polystyrene products, which are disposed of after only a single-use, polypropylene can be reused over and over again without having to replace them. Therefore, polypropylene products can be considered as cost-effective alternatives to their glass equivalent. There are however still many applications where glass is still preferred and necessary. The durability, high chemical resistance, and high level of temperature tolerance of polypropylene products make them very versatile in many laboratory and industrial applications.
Polystyrene
Polystyrene also identified as PS is a polymer made from the monomer styrene, a liquid hydrocarbon that is commercially manufactured from petroleum. At room temperature, polystyrene is normally a solid thermoplastic but can be melted at a higher temperature for extrusion, then resolidified. Styrene is an aromatic monomer, and polystyrene is an aromatic polymer. Polystyrene is a hard and rigid material used to make toys, kitchen appliances, disposable drinking cups, packaging material, computer housing parts, etc. It is a highly used plastic all over the world because it is usually offered at a lower price point than many other plastics. Polystyrene is environmentally friendly because it can be recycled. Although polystyrene offers some resistance to acids and bases, it is not as resistant against some chemicals as polypropylene. Polystyrene products are usually consumed in large quantities as they cannot withstand heat above 100°C and are disposed of after only a single-use. Polystyrene is great for general sample storage and transport and is commonly used in lab supplies such as test tubes, microplates, and Petri dishes due to is glass-like transparency.
FAQs
Chemical resistance: polystyrene has some acid and base resistance, although not as much as polypropylene against some chemicals. Reusability: polystyrene products are typically used in huge amounts and are disposed of after one use since they cannot tolerate temperatures beyond 100°C.
What is the difference between polystyrene and polypropylene? ›
PP is known for its high tensile strength, impact resistance, and toughness. It exhibits good resistance to fatigue and stress cracking. In contrast, PS is relatively brittle and has lower impact resistance compared to PP. PS is also more prone to stress cracking under certain conditions.
What is the difference between PP and polypropylene? ›
Polypropylene is widely used in its hom*opolymer form, which contains only propylene monomers. Adding ethylene into the polymerisation process creates PP copolymers. These have slightly different characteristics to the virgin material, including varying melting temperatures between 266°F and 338°F.
What is the difference between polystyrene and polyethylene? ›
For example, while polyethylene is much more resistant and durable in HDPE and UHME forms making it more practical for construction packaging, polystyrene is easily shaped and formed, so this makes it more ideal for engineering packaging purposes than polyethylene.
What is the difference between styrene and propylene? ›
Polypropylene plastic has a shinier surface and a higher heat tolerance than polystyrene. Polystyrene cutlery features a denser design and is not as bendable as polypropylene cutlery so they are more prone to breaking under heavy pressure.
Which is stronger, polypropylene or polystyrene? ›
Polypropylene has a stronger compressive strength than polystyrene. It is a more stiff and long-lasting material that can handle larger compression loads.
Which is stronger polyethylene or polystyrene? ›
While polystyrene and polyethylene share a few similarities, they have a few defining differences. In its HDPE and UHME forms, polyethylene is far more impact resistant and durable, making it ideal for use in construction. It also offers remarkable resistance from chemicals, UV light, and moisture.
What chemical dissolves polypropylene? ›
Polypropylene at room temperature is resistant to fats and almost all organic solvents, apart from strong oxidants. At elevated temperature, PP can be dissolved in nonpolar solvents such as xylene, tetralin, and decalin.
Which is stronger, polypropylene or polyethylene? ›
The main differences with polyethylene are that polypropylene is lighter and more resistant to high temperatures, abrasive agents and chemical solvents. It is also more resistant to breakage, however, it is less flexible than polyethylene. Another major advantage is that it is easy to colour and mould.
Which is safer, polypropylene or polyethylene? ›
Of the two, polypropylene can withstand higher temperatures. It is more rigid and has a higher melting point than polyethylene. Also, polypropylene is used in food packaging, as it is food-safe and moisture-resistant.
Polypropylene is not as sturdy as polyethylene. Polypropylene is stiffer and resistant to chemicals and organic solvents compared to polyethylene. Polypropylene is pure, non-stretching and generally more rigid than polyethylene.
Why was polystyrene banned? ›
Animals do not recognize polystyrene foam as an artificial material, may mistake it for food, and show toxic effects after substantial exposure. Full or partial bans of expanded and polystyrene foam commonly target disposable food packaging.
What is better than polystyrene? ›
WoolPack has been proven to outperform polystyrene packaging. It's a great option for fresh foods, seafood, chocolates, pharmaceuticals and other products that need to be in a stable temperature during transport. Woolpack wool felts are 100% biodegradable, compostable and sustainable.
What are the disadvantages of polypropylene? ›
Polypropylene disadvantages
Other recycling or re-conditioning methods must be considered, at a significantly higher cost. This low melting point also means that polypropylene is highly flammable and limited in its ability to withstand higher temperatures and it is also susceptible to UV degradation and oxidation.
What is safer polyethylene or polypropylene? ›
Of the commercial plastics on the market today, polypropylene is considered one of the safest.
Which is better polypropylene or polyethylene? ›
Of the two, polypropylene can withstand higher temperatures. It is more rigid and has a higher melting point than polyethylene. Also, polypropylene is used in food packaging, as it is food-safe and moisture-resistant. Polypropylene finds its way into packaging, carpets, ropes, and plastic parts.
Which is better polystyrene or polyurethane? ›
Polyurethane demonstrates about twice the resistance to heat that polystyrene manages and is an excellent material for electrical insulation. In addition, polyurethane continues to maintain flexibility in very cold conditions, though a gradual stiffening begins at 0 degrees Fahrenheit.
