TPE elastomer has been widely used in many fields due to its unique molecular structure and performance advantages, but low temperature environment has become an important factor to test its performance. Flexibility and resilience are the key characteristics of TPE elastomer. At low temperatures, they will change significantly due to changes in molecular motion and changes in the internal structure of the material. These changes directly affect the use effect and life of TPE products.
In a low temperature environment, the movement of the molecular chain segments inside the TPE elastomer becomes slow. The flexibility and resilience of TPE materials mainly depend on the free activity of the molecular chain. At room temperature, the molecular chain can change its conformation relatively easily, giving the material a good soft touch and elastic recovery ability. However, when the temperature drops, the molecular thermal motion weakens, the activity space of the molecular chain segments is limited, and the interaction force between each other is enhanced, making it difficult for the molecular chain to stretch and curl. Just like people's limbs become stiff in cold weather, the molecular chains of TPE elastomer are also "frozen", and the material gradually loses its soft properties and begins to become hard and brittle.
As the temperature continues to drop, the resilience of TPE elastomer will also be seriously affected. The rebound process is essentially the process in which the molecular chain recovers from the stretched state to the curled state after the material is deformed by force. At low temperatures, the ability of the molecular chain to recover the curled conformation decreases. When the external force is removed, some molecular chains cannot rebound to the initial state in time, resulting in permanent deformation of the material. TPE products that can quickly recover their shape at room temperature will retain a certain degree of deformation after being stretched or compressed at low temperatures and cannot be completely restored. This phenomenon will seriously affect the performance of the product in application scenarios such as seals and shock absorbers that have high requirements for rebound.
The composition of TPE elastomer also plays a key role in the change of low-temperature performance. Different types of TPE, such as styrene, polyolefins, polyesters, etc., have different performances at low temperatures due to differences in their base polymers and additives. Some TPE materials improve flexibility by adding specific plasticizers, but in low-temperature environments, the compatibility of plasticizers with polymer molecules may deteriorate, and plasticizers gradually precipitate or lose their effect, which increases the hardness of the material and further reduces its flexibility. The glass transition temperature of the rubber phase or elastic chain segment introduced in some TPE materials determines the lower limit of the temperature at which the material maintains elasticity. When the temperature is lower than this limit, the rubber phase undergoes a glass transition and loses elasticity, which in turn affects the overall flexibility and resilience.
Low temperature environment will also affect the microstructure of TPE elastomer. During the cooling process, microphase separation may occur inside the material, and the originally uniformly dispersed phase structure gradually becomes unstable. For some crystalline TPE materials, low temperature will cause the molecular chains to arrange regularly to form crystalline regions. Although the increase in crystallinity enhances the hardness and strength of the material, it sacrifices flexibility and resilience. The existence of crystalline regions limits the movement of molecular chains, making the material rigid, and the crystalline structure is difficult to recover after deformation under force, resulting in a decrease in resilience, just like the frozen lake surface loses the fluidity of water.
In practical applications, changes in the performance of TPE elastomer products at low temperatures may cause a series of problems. For example, TPE sealing strips used outdoors in winter are difficult to fit tightly into gaps due to reduced flexibility, resulting in poor sealing effect and easy penetration of wind and snow; TPE components used for automotive shock absorption, insufficient rebound performance will greatly reduce the shock absorption effect, affecting driving comfort and safety. These problems not only reduce the use value of the product, but also may cause potential quality risks.
In order to improve the flexibility and rebound performance of TPE elastomer in low temperature environments, material developers have adopted a variety of strategies. By adjusting the formula, selecting base polymers and plasticizers with excellent low-temperature performance, the molecular chain activity of the material at low temperatures is enhanced; adding special additives such as cold-resistant agents and low-temperature modifiers to reduce the glass transition temperature of the material and broaden its elastic use temperature range; optimizing the processing technology, controlling parameters such as temperature and pressure during the molding process, and avoiding internal structural defects of the material due to improper processing, which affects the low-temperature performance. In addition, polymers with different properties can be compounded through modification technologies such as blending and copolymerization to complement each other and improve the overall low-temperature adaptability of TPE materials.
Although low temperature environment brings many challenges to the flexibility and resilience of TPE elastomer, with the continuous development of material science and continuous innovation of technology, people are gradually overcoming these difficulties through reasonable formula design, advanced processing technology and in-depth performance research. In the future, TPE elastomer with better performance will play a role in more low temperature application scenarios, providing strong support for the performance improvement and function expansion of products in various industries.
