The properties of the polymer depend on what they are made from and the conditions under which they are made. Low density and High density poly(ethene) are produced using different catalysts and reactions conditions.
Thermosetting polymers consist of cross links between the polymer chains so they don't melt when heated.
Thermosoftening polymers consist of individual, tangled polymer chains.
Polymers have many useful applications.
New packaging methods Dental polymers waterproofing fabrics wound dressings Hydrogels
Polymers are not biodegradable. so microbes can't break them down.
plastic bags are being made from polymers and cornstarch so they break down more easily. Biodegradable bags are being made from cornstarch and are being developed.
High density - few branches on polymer molecules Low density - many branches on the polymer molecule