urethane vs polyurethanev vs rubber bushings difference

[68 SuperRam]

Can someone help educate me more on what is the difference between urethane vs polyurethane vs rubber bushings?

Also would be curious to know what products / grease can be used to install these types of bushings?

I was told that Wd40 Silicone can be used for rubber bushings (body mount) and suspension parts to help against cracking / drying out.



For polyurethane - Energy Suspension has a grease that is used for bushing installation.

What about urethane - was told that dielectric grease can be used for installation.

Thanks