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What is Polyurethane?

By S. Mithra
Updated May 17, 2024
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Polyurethane is a resilient, flexible and durable manufactured material that can take the place of paint, cotton, rubber, metal or wood in thousands of applications across virtually all fields. It can be hard like fiberglass, squishy like upholstery foam, protective like varnish, bouncy like rubber or sticky like glue. Since its invention during the 1940s, polyurethane has been used in a wide range of items, from baby toys to airplane wings, and it continues to be adapted for contemporary technology.

How it is Made

This substance is categorized as a polymer — a molecule that consists of a series of repeating smaller units called monomers — based on its chemical structure. It is manufactured by combining two types of compounds, a diisocyanate and a diol, which are monomers, through a chemical reaction. This makes a basic material whose variations can be stretched, smashed or scratched and will remain fairly indestructible. Depending on the different diisocyanates and diol or polyol constituents, the resulting polyurethane might be in the form of a liquid, foam or solid. Each form has its own advantages and limitations.


Some polyurethane is categorized as an elastomer. It has elastic properties while maintaining some rigidity, which is beneficial for items such as the wheels of a dolly, which must absorb shock without compressing too much. Polyurethane can be extremely flexible when used as a foam insulator in construction or a foam cushion in upholstery. It can be deformed over and over and still maintain its original shape. In other words, it has what is called structural memory.


Other polyurethane is a thermoplastic that resembles other kinds of plastic, metal or fiberglass. Thermoplastics are rigid and smooth, with a sealed surface that is impermeable to water. These are used when strength and durability are important, such as in seats at an airport terminal or packaging crates on a truck. Some polymer thermoplastics are difficult to recycle, but they can be reused.

Many Other Uses

Polyurethane can be found in every room of the house and in practically every building. Since this material became popular during World War II, the polymer has protected, reinvented, joined or transported countless items. It seals surfaces such as wood, metal and paint to protect them from rot, corrosion or fading. As an adhesive, polyurethane resists moisture and heat, so it is ideal for use in the sun or underwater. It also insulates walls, temperature-controlled vehicles and consumer coolers.

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Discussion Comments
By anon354472 — On Nov 08, 2013

Polyurethane is a better alternative than leather for the environment.

By anon330262 — On Apr 15, 2013

A more accurate definition should read: "Polyurethanes are macro-molecular products, the result of polyadition reactions of isocyanates with polyols."

By anon320660 — On Feb 19, 2013

Can we use polyurethane as a coating material on cotton yarns in order to remove hairiness and also to add strength in yarn?

By anon318236 — On Feb 06, 2013

At the top of this page it says that polyurethane is used for baby toys. I would like to know more about this since I have a product idea that needs to be safe against skin and for children. This sounds good to me but I need more information about it.

By anon282512 — On Jul 30, 2012

How is PU used in infusion sets?

By lovergirl — On May 22, 2012

My hubby is going to be deployed and before he leaves I want to mold a dildo using his penis in polyurethane. Is it safe?

By anon268913 — On May 16, 2012

I got a polyurethane rubber roller and it got deformed before using after four months. What could have caused this?

By anon255009 — On Mar 15, 2012

Would polyurethrane be used for tires?

By anon241345 — On Jan 18, 2012

To anyone trying to use PU to build anything in which you will use for farming/growing/planting your own foods: it is a very bad idea. PU emits gases that are hazardous to your health. These gases will get trapped in the soil, then grown into your veggies.

Using wood to build a growing box or planter is much safer and healthier for your vegetables and you.

By anon237206 — On Dec 28, 2011

can you use polyurethane on a wood outside deck.

By anon206939 — On Aug 18, 2011

is it possible to reuse hard polyurethane residues to make something?

By anon153323 — On Feb 17, 2011

i want to use polyurethane to make flower and vegetable bed on my terrence. where can i get this material? is this sold by meter? what is the approximate cost of it?

By anon144886 — On Jan 21, 2011

@anon13037: Did you ever get any answers for your questions? I am interested in some of the same answers if you have them. Please post back. --sk8trgrl

By anon138961 — On Jan 03, 2011

I recently purchased a mattress topper made of polyurethane and slept put it on my bed for two hours and got so sick.

I took it off the bed and left it in the garage for five days, then put it back on my bed. Again, I was only able to leave it on the bed for about an hour. I got sick again. I was sick for several days and now I'm scared to even try it again!

I am very disappointed because my daughter bought the exact same mattress topper and raves about how awesome it is to sleep on. Is it just me? Should I give up on the idea of sleeping on it? I'm sure you can agree, after the past attempts to use it, and having such bad results, I'm afraid to even try it anymore. Is this a common complaint? Or is it just me?

By anon135122 — On Dec 17, 2010

Polyurethane when in its unmixed elements, Polyol and Isocyanate can be harmful. When it is mixed it also gives off a gas which is probably the most dangerous form. However, once it is mixed it is pretty much inert. That's why they use PU in buildings using SIPS panels. Very high melting point and it's inert.

By anon110136 — On Sep 10, 2010

I have a jacket that I thought was leather but it says it is polyurethane, and it is very wrinkled. any suggestions to get the wrinkles out.

By anon104123 — On Aug 15, 2010

good website. lots of helpful info.

By anon84786 — On May 17, 2010

if bushings for vehicle suspension are made from polyurethane, can these bushings be greased without them getting damaged like rubber?

By anon73538 — On Mar 28, 2010

Heating of any PU material (e. g. soft foam, paint dust after sanding, textiles, PU painted flooring etc.) should be avoided at any cost. Polyurethane polymer dust can cause mechanical irritation to the eyes and lungs.

Proper hygiene controls and personal protective equipment (PPE), such as gloves, dust masks, respirators, mechanical ventilation, and protective clothing and eye wear should be used. Clothes should be changed and hands, hair and face should be cleaned before smoking.

By anon70952 — On Mar 16, 2010

Can this product be used for water storage,and would the water be safe to drink?

By anon66054 — On Feb 17, 2010

I need to know the answers given to #3 and 13. I have a worker who believes they have an allergic reaction to the protective sleeves use here at work.


By anon62222 — On Jan 25, 2010

looking for a chart the shows the difference between polyurethane and polyethylene. Looking for tubing that has better strength with the same chemical resistances and basic price as polyethylene

By anon58789 — On Jan 04, 2010

I want to get a bag which is '100 percent polyurethane' and I'm hoping it's waterproof. Any ideas?

By anon57043 — On Dec 19, 2009

I have to write a three to five page report on polyurethane. What should I write about?

By anon53720 — On Nov 24, 2009

i want know the types and code of polyurethene material, with reference to color.

By anon53505 — On Nov 22, 2009

i am doing a presentation on Polyurethane for my A Level physics coursework. I have chosen to do it on the uses in the automotive industry but am finding it hard to find more information past the basics online. any help would be appreciated hugely.

By anon50492 — On Oct 29, 2009

How is polyurethane used in making elastane?

By anon48557 — On Oct 13, 2009

What kind of polyurethane can be used for coating objects to make them float?

By mfaslam — On Sep 16, 2009

What kind of Polyurethane foam is required for noise absorption?

By anon45241 — On Sep 15, 2009

What is the chemical carbon compound of polyurethane?

By anon44228 — On Sep 06, 2009

all the chemicals are harmful to our to health including PU, but it will be fine for adults if it existd in small amounts. i advise you not move in before the cleaning had been done since you had a child, because of the harmful smell. The curing time(time for drying) depends on the temperature of your house.

By anon43257 — On Aug 27, 2009

one of the applicators introduced me to the PU coating for my floor. But i'm not so familiar with the PU. is PU poisonous? as i come across article regarding the starting material for PU is isocyanate. is it harmful to my health? During the applicator will it emit any poisonous gas?

By anon42437 — On Aug 21, 2009

i want to know about the usage of PU melting point?

By anon37382 — On Jul 19, 2009

what are polyurethane made sofas? are they any good in respect of durability and there lifespan.

do they require much upkeeping or not? any other benefits would be appreciated.

By anon36530 — On Jul 13, 2009

I'm going to paint my white external door with PU because i'm sick of repainting due to humidity effect. Should I paint the kitchen and bathroom marble floors too? Is it the same material?

By anon34094 — On Jun 17, 2009

i working in heater industry. we using polyurethane as thermal insulation, in that using 2 type of polyurethane is black and white, which having different density. i want the details of that insulation material(polyurethane) which using as thermal insulation between the outer cover and boiler.

By anon33409 — On Jun 05, 2009

can you be allergic to this product?

By anon33284 — On Jun 03, 2009

All these good questions and no answers!

What is going on here?

By mikegbi — On May 05, 2009

What are the various methods for cutting out the hard polyurethane for electrical boxes and chases?

Is a router recommended?

By anon24384 — On Jan 11, 2009

How this product naming "Polyurethane" is used in carpet industry, with polyurethane features.

What is the market price and in which quantity it is available (kg / litres etc) ?

By anon24145 — On Jan 07, 2009

i would like to know the procedure to evaluate the surface area of a polyurethane foam cube. What are the common values?

By anon20455 — On Oct 31, 2008

hi can you please let me know the thermal property

such as mass burning rate and effective heat of combustion for polyurethane?

By anon17609 — On Sep 02, 2008

i polyeurathaned the other day. the next day i almost fainted twice, something that had never happened before and today i had trouble seeing out of one eye for 30 min. the dust is probably worse and i suggest that you stay away from it. i am not positive that the polyurethane caused this but better safe than sorry.

By anon16795 — On Aug 15, 2008

how long does polyurethane take to dry? is weather a factor?

By anon16718 — On Aug 13, 2008

Is polyurethane toxic? Does it cause any side affects?

By anon13037 — On May 18, 2008

I live in a small New York City apartment. I recently had my bathroom tiles glazed with urethane. Unfortunately, the glazer somehow managed to spray the urethane all over my entire apartment. It looks like there is a thin layer of dust on every surface in the apartment, including the couch, the pillows, the floor, the tv, the coffee table and the chairs. I am in the process of obtaining a professional cleaning service to clean the apartment, however, the procedure is very costly and I am dealing with a slow insurance company. I am not sure when the cleaners will be able to start.

I have a 2 year old child and am very very worried about having my child come in contact with the glaze. Is the substance toxic? We have been out of the apartment for 3 days. Should I be worried about returning before the cleaning service cleans the apartment?

Any advice or suggestions would be greatly appreciated.


Super Stressed Out Mom

By radki — On Jul 27, 2007

To produce polyurethane in "tape" form what are the raw materials and what is the process?

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