The Difference Between Polyurethane Elastomers And Rubber

Elastomers are used frequently in the field of rubber synthesis and processing as technical terms. But when people understand or use it, they often question whether it is the same concept as rubber, whether there is a difference in time between the two, whether it can be used for each other.

Polyurethane Urethane Rubber

Polyurethane and polyurethane rubber is one thing. Because polyurethanes have good resilience, they are often referred to as polyurethane rubber, also known as polyurethane elastomer.

Urethane Rubber is characterized by high hardness, high elasticity and wears resistance compared to other rubber materials, while ageing resistance, ozone resistance and oil resistance are also excellent, with temperatures ranging from -45 to 90 degrees C.

Polyurethanes are polymerized from polyester (or polyether) and diazomethane compounds. Good wear resistance, followed by good elasticity, high hardness, oil resistance, solvent resistance. The disadvantage is poor heat ageing resistance. Polyurethane rubber is most used in the automotive, shoe and machinery industries. Whether polyurethane should be classified as plastic or rubber depends on the actual situation.

Rubber

Rubber is taken from rubber trees, rubber grass and other plants of latex, processed into an elastic, insulating, impermeable and air-inflatable material. Highly elastic polymer compounds. It is divided into natural rubber and synthetic rubber. Natural rubber is a natural polymer compound with a chemical molecular formula of (C5H8)n, which is made after extracting gel from plants such as rubber trees and rubber grasses. Polyisoprene is its main component, the rest of fatty acids, sugars and other substances. Synthetic rubber is obtained by the polymerization of various monomers. Rubber products are widely used in industry or all aspects of life.

Rubber is made from latex, which contains a portion of the non-rubber components left in solid natural rubber. General natural rubber contains 92%-95% of rubber hydrocarbons, while non-rubber hydrocarbons account for 5%-8%. Due to different methods, different origins and even different seasons, the proportion of these ingredients may be different, but basically within the scope.

Rubber is an organic polymer with a molecular weight of hundreds of thousands. It differs from other industrial materials in four ways:

● Can maintain high elasticity in a large temperature range (-50-150 degrees C);

● Low elastic modulus, 3 orders of magnitude lower than ordinary materials;

● The elongation rate can reach up to 1000% (general material is less than 1%);

● When stretching, heat is released, while the general material absorbs heat; Fifth, elasticity increases with temperature, which is also the opposite of general materials.

As you can tell from above, the properties of polyurethane rubber and rubber are overlapping, in general, that is, "low modulus, high extension", but the two are not the same, at least the following two aspects:

The superior properties of rubber often require crosslinking (vulcanization) before they can be fully utilized, whereas some elastomers do not.

Some elastomer materials can be manufactured directly by plastic processing methods without cooperation, refining, vulcanization and other traditional rubber processes.

Rubber and polyurethane are two different materials. The advantages of its use are also slightly different:

Benefits of polyurethane rubber:

Excellent wear performance: The wear resistance is the highest of all rubbers. Laboratory results show that the wear resistance of UR is 3 to 5 times that of natural rubber, and in practical applications, it is often as high as about 10 times.

High strength and good elasticity in the hardness range of A60 to Shore A70.

The cushioning damping is good. At room temperature, the UR shock absorption element can absorb 10% to 20% vibration energy, the higher the vibration frequency, the greater the energy absorption.

Good oil and drug resistance. UR is less affinity with non-polar mineral oils and is virtually unsubsidized in fuel oils (e.g. kerosene, gasoline) and mechanical oils (e.g. hydraulic oil, oil, lubricants, etc.), much better than general rubber and comparable to butyl rubber. The disadvantage is that the swelling is greater in alcohols, esters, ketones and aromatics.

The coefficient of friction is high, - like above 0.5.

Low-temperature resistance, ozone resistance, radiation resistance, electrical insulation, bonding performance is good.

Disadvantages of polyurethane rubber:

Poor flame retardant performance, fast combustion speed and excessive droplets in the process, easy to lead to the accelerated spread of fire. In addition, polyurethanes produce more toxic gases when burned, mainly carbon monoxide (CO).

Benefits of natural rubber:

The natural rubber has better elasticity and strong mechanical strength at room temperature. Low heat when deformed multiple times. Because it is non-polar rubber, it has good electrical insulation.

Disadvantages of natural rubber:

Different rubber components make different kinds of rubber joints to suit their media. Natural rubber is good, but not all areas can be used. For other media, in different environments, natural rubber is greatly limited. According to the local climate environment, medium soil and other production suitable for local rubber joints for construction sites, community water supply and drainage systems and other uses.