Physical Properties of Rubber: What Engineers Need to Know

Learn how the physical properties of rubber effect compound selection.

Engineers and part designers need to select rubber materials that meet all of their application requirements. Elastomers such assiliconeshave inherent physical properties, but these properties can be enhanced through compounding.

During compound selection then, it’s important to understand a rubber’s physical properties and to know how each property is measured. This will help you to ask for and receive the compound that you really need.

What are the physical properties of rubber?

These are the physical properties of rubber.

• Hardness
• Tensile Strength
• Tensile Modulus
• Elongation
• Resilience
• 压缩集
• Tear Resistance
• Abrasion Resistance
• 比重

The following sections provide a high-level look at each physical property. Future articles in this series will examine each property in greater detail.

Hardness

Elastomers have an inherent hardness because of their chemical structure. This hardness can be modified, and the processed hardness then measured in terms of durometer (duro) on a Shore scale. For soft to medium-hard rubber, Shore A is used. At 40 duro, solid rubber profiles have the consistency of pencil erasers. At 90 duro, they’re hard like hockey pucks. Which hardness do you need?

Tensile Strength

拉伸强度（TS）是将橡胶标本拉开直至破裂所需的力量。根据ASTM D412，TS也称为最终拉伸强度（UTS），以每平方英寸（PSI）或巨质的测量。对于技术买家和零件设计师而言，拉伸强度很重要，因为它代表了橡胶的伸展引起的故障点。

Tensile Modulus

Tensile modulus (TM) sounds similar to tensile strength, but these two properties are not the same. TM is the force or stress that’s required to produce an elongation percentage or strain in a rubber sample. In general, harder rubber has a higher tensile modulus. Such rubber is more resilient, but also more resistant to extrusion, a process for manufacturing stock materials used in custom fabrication.

Elongation

伸长是施加拉伸力（应力）的橡胶样品的原始长度的百分比增加（应变）。有些弹性体比其他弹性伸展更多。例如，天然橡胶（NR）可能在达到NR破裂的那一刻之前伸展到700％。相比之下，荧光弹性物可能以300％的伸长率破裂。您需要多少橡胶零件才能拉伸？

Resilience

Resilience or rebound refers to a rubber’s ability to regain its original shape and size after a temporary deformation, such as contact with a metal surface. Resilience is especially important in dynamic seals, components that create a barrier between moving and stationary surfaces. If your application requires weatherstripping between a door and a door frame, the compound’s resilience is important to consider.

压缩集

压缩集是释放压缩负荷后弹性体无法返回其原始厚度的数量。当橡胶密封随着时间的推移反复压缩时，会发生渐进的应力松弛。就印章的生活而言，压力放松就像死亡。压缩组就像死亡本身 - 密封力稳定下降的最终结果。您需要密封持续多长时间？

Tear Resistance

Tear resistance describes an elastomer’s resistance to the growth of a nick or cut when tension is applied. Also known as tear strength, this physical property is measured in either pound force per inch (lbf/in) or kilonewtons per meter (kN/m). If you need edge trim that will contact rough metal edges or sharp objects, consider tear resistance during compound selection.

Abrasion Resistance

耐磨性描述了一种橡胶的抵抗力，无法磨损摩擦或刮擦。在工业应用中，耐磨橡胶与移动煤炭和处理湿润的泵中的输送带一起使用。根据ASTM D394等测试，可以用各种仪器测量磨损造成的材料损失。

比重

比重是在指定温度下材料的重量与相等水量水的重量的比率。对于化学家来说，它提供了一种识别化合物的方法。对于技术买家和零件设计师来说，重要的是要知道，特异性重力低的橡胶提供每磅股票更平方英寸的橡胶。具有较高特异性重力的橡胶在成型一致性方面具有优势。

您需要定制密封吗？了解有关橡胶物理特性的更多信息。

Do you have questions about the physical properties of rubber?Contact Elasto Proxyfor more information, and enjoy the short video below that accompanies this article.