Physical properties of silicone rubber

Q: Physical properties of silicone rubber

Products used in life, including household appliances, kitchen supplies, electronic products, will use silicone rubber products as accessories. Today, ES silica gel is going to talk about what kind of physical characteristics make silicone rubber products so popular. 

1. viscosity. Viscosity refers to the volume characteristics of anti flow of liquid, pseudo liquid or pseudo solid substance, that is, the internal friction or internal resistance between molecules when flowing under the action of external force Generally, viscosity is directly proportional to hardness.

2. hardness. The ability of a material to partially resist hard material pressing into its surface is called hardness. Silicone rubber has a 10 to 80 shore hardness range, which gives designers full freedom to choose the required hardness to best achieve specific functions. Various intermediate hardness values can be achieved by mixing polymer substrates, fillers and additives in different proportions. Similarly, the time and temperature of heating curing can also change the hardness without destroying other physical characteristics.

3. Tensile strength. Tensile strength refers to the force required on each range unit to cause tearing of a rubber material sample. The tensile strength range of the vulcanized silicone rubber is between 4.0-12.5mpa. The tensile strength of fluorosilicone rubber is between 8.7-12.1mpa. The tensile strength range of liquid silicone rubber is between 3.6-11.0mpa.

4. Tear strength. The resistance to apply force to a notched specimen to impede the expansion of the notch or notch. Even if it is placed under extremely high torsional stress after cutting, the hot vulcanized solid silicone rubber can not be torn. The tear strength range of hot vulcanized solid silicone rubber is between 9-55 kn / m. The tear strength of fluorosilicone rubber is in the range of 17.5-46.4 kn / m. The tear strength of liquid silicone rubber is between 11.5-52 kn / m.

5. Elongation. It is usually referred to as "ultimate rupture elongation" or the percentage increase relative to the original length when the sample breaks. The general elongation range of hot vulcanized solid silicone rubber is between 90% and 1120%. The general elongation of fluorosilicone rubber is between 159 and 699%. The elongation of liquid silicone rubber is generally between 220% and 900%. Different processing methods and selection of hardener can change its elongation to a great extent. The elongation of silicone rubber is closely related to temperature. 

6. Operation time. The operation time is calculated from the moment when the colloid is added to the vulcanizer. There is no complete boundary between this operation time and the subsequent vulcanization time. The vulcanization reaction of the colloid has been carried out since the moment when the vulcanizer is added. This operation time means that the 30 minute vulcanization reaction of the product can not affect the quality of the finished product. Therefore, the more time is saved in the process of product operation, the more favorable to the finished product.

7. Curing time. Some places will say curing time. That is to say, the vulcanization of silica gel is basically over after such a long time. This basically means that the product is available, but in fact, a small part of the curing reaction is not over. Therefore, products made of silicone rubber, such as silicone mold, are usually put into use for a period of time.