Rubber

With an increase in the scope of rubber manufacturing, it has become a requirement for companies to assure the quality of rubber being used in the field to meet the design requirements. To aid this purpose, MICROLAB has added facilities to test the mechanical properties as well as chemical requirements of rubber.

MICROLAB has the state-of-art equipment as well as trained personnel needed to guarantee high confidence results

The current parameters that can be tested are:

  • Durometer hardness
  • Specific gravity/density
  • Compression Set
  • Ash content
  • Accelerated Heat Ageing
  • Resistance to ASTM Oil, Water and Fuel
  • Abrasion Resistance
  • Polymer identification (proximate analysis)
  • Tensile, Elongation and Hardness properties
  • Tear Strength

The test methods comply with IS-3400 and ASTM standards

For further information on the test procedure or tailor the test based on your requirements, contact us directly

  • Durometer hardness

The hardness of rubber is the material’s resistance to permanent indentation

MICROLAB has experience in determining the hardness of the rubber used in the application, and can measure up to a hardness of 90 Shore A.

The hardness is measured as per IS-3400  PART-2 / ASTM D-2240. In this method, the property is determined by a series of test with a durometer and ultimately obtaining the results based off the elastic modulus and viscoelastic behavior of the sample

  • Specific Gravity/Density

Specific gravity is the mass per unit volume and is measured by weighing the sample in air and water

This property is useful in understanding the loss of plasticity, absorption of solvents, thermal effects, etc. and it mainly benefits the organization to select the right rubber based on cost-to-weight and strength-to-weight ratios.

The testing at MICROLAB follows IS 3400-Part 9/ ASTM D-792

  • Compression Set

Compression set tests are designed to measure the ability of rubber compounds to retain elastic properties after prolonged action of compressive stresses. In applications where continuous application of a known static force is present, this property will determine the suitability of the right rubber material. Dynamic loads are however simulated only through hysteresis tests. MICROLAB can carry out the compression set test at varying temperatures as well as time to best depict service conditions.

This procedure is as per IS:3400 Part 10/ ASTM D-395

  • Ash content

The amount and type of some or all of the major constituents can be determined on crude, unvulcanized, reclaimed and vulcanized rubbers. This test can detect ash content from which carbonates, Antimony, Lead, Carbon Black, Barium salts, Waxy Hydrocarbons, Glue, alcoholic potash and other fillers and extracts are determined.

This procedure is as per IS:3400 Part 22/ ASTM D-297

  • Accelerated Heat Ageing

The properties of rubber vary drastically depending on the time caused during oxidation as well as thermal aging. The rubber should resist deterioration through such effects, and thus this property can be useful. Although the exact service conditions cannot be simulated, it is useful to compare laboratory conditions for different rubber compounds. MICROLAB can vary the temperature and time depending on customer requirement, after which physical properties like elongation, tensile, changes in volume/weight, hardness are quantified.

This procedure is as per IS:3400 Part 4/ ASTM D-573

  • Resistance to Oil, Water and Fuel

Rubber has a wide range of applications which see them in contact with oil, water and fuel. Some of these examples include gaskets, seals, diaphragms, hoses, sleeves etc. The properties of rubber vary over time and also under the influence of service temperature and must be evaluated under such conditions. The testing done at Microlab uses a controlled accelerated testing for different ASTM oil (1,2 and 3) and fuel (A - H). The physical properties after immersion are measured.

This procedure is as per IS:3400 Part-6/ ASTM D-471

  • Abrasion Resistance

Rubber used in harsh conditions like in the cases of tires, conveyor belts, transmission systems, hoses, footwear it is imperative to understand the wear characteristics. The abrasion resistance is a measure of the overall durability of the rubber. Rotary drum abrasion  measures the volume loss due to the abrasive action of rubbing a test piece over a specified grade of abrasive sheet. The result can be reported as a relative volume loss or an abrasion resistance index.

This procedure is as per IS:3400 Part-3/ASTM 5963

  • Polymer identification

MICROLAB performs pyrolysis test which involves vaporizing the rubber and passing the resultant vapor through an acid solution to determine the nature of polymer.

This procedure is as per IS:3400 Part-22

  • Tensile, Elongation and Hardness properties

The fundamental physical properties like the tensile strength, young’s modulus, elongation and hardness properties can be determined. These quantities can be used to choose the right rubber for the application.  The properties depend on the temperature, relative humidity, specimen geometry, extension rate etc.)

The procedure is as per IS:3400 Part-1/ASTM D-412

  • Tear Strength

The force required to cause a cut in the rubber to extend by tearing of the rubber, acting substantially parallel to the major axis or normal to the plane of the cut.

Tear strength may be influenced to a large degree by stress-induced anisotropy (mechanical fibering), stress distribution, strain rate, and test piece size. The significance of tear testing must be determined on an individual application or product performance basis.

The sample can be prepared either as angular or cresent  based on the best representation of the application the rubber is being used.

The procedure is as per IS:3400 Part 12 & 17/ ASTM D-624