Is polyurethane and polyurethane rubber one thing?
Polyurethane and polyurethane rubber are one thing. Because polyurethane has good resilience, it is often called polyurethane rubber, also known as polyurethane elastomer.Polyurethanes are polymerized from polyesters (or polyethers) and two isopropyl esters. Good wear resistance, followed by good elasticity, high hardness, oil resistance, solvent resistance. The disadvantage is heat aging, poor performance. Polyurethane rubber is the most widely used in automobile, shoemaking and machinery industry.Whether polyurethane should be classified as plastic or rubber depends on the actual situation.
Polyurethane, plastics and rubber are made of polyurethane resin polymer composite material, the specific material and production process is different, resulting in polyurethane polymer chain molecular weight and performance of different.Polyurethane can also be used in coatings, adhesives and other fields, the use is very extensive.
The biggest difference between the plastic and the rubber is the performance of the plastic properties of high tensile strength, but low toughness, toughness and rubber are relatively high, mainly related to the glass transition temperature of material, high glass transition temperature of plastics, because of its high hardness, low toughness.
Plastics, such as Taiwan and Hongkong, are commonly referred to as plastics, so there is little point in distinguishing between plastics and rubber. From a theoretical point of view, the distinction between plastic and rubber is generally based on whether the glass transition temperature (Tg) of the material is above normal or below normal. Polymers that are generally less than Tg at normal temperature are called plastics (e.g., polyethylene, Tg, -78 degrees), while polymers with Tg temperatures higher than normal are called rubber.
Polyurethane is a very special polymer, it is composed of hard and soft segments, the hard part of Tg is very low, with plastic characteristics, soft section of Tg is higher than room temperature, a lot of rubber characteristics. In the process of synthesis of polyurethane, by controlling polymerization, the proportion of hard segment and soft segment of polymer can be adjusted, so that polyurethane can be expressed as plastic or rubber.Rubber shoes, excluding plastic shoes, should not be included in general sense. Common sense says in rubber overshoes, it is the waterproof shoe that rains commonly, army shoe, plastic shoe has slipper commonly.
