Issue link: https://te.mouser.com/i/1385324
32 Proven in the Harshest Environments Although the majority of applications were for typical settings—such as the connection of standard cables and terminations—utility and industrial applications developing needs went beyond everyday environments, such as: • High UV requirements • Heavy pollution areas • Salt fog environments • Oil barrier properties • Flame retardant properties • Fire resistance and system integrity • Gamma radiation resistance • Functionality under a loss of coolant accident (LOCA) conditions Heat-Shrink Technology The base material for the heat-shrink technology is polyethylene-based molecule chains. These are subjected to cross-linking processes such as chemical or radiation cross-linking. In a radiation cross-linking process, multi MeV electron accelerators are used, where electrons are accelerated to gain such high energy that they can initiate the cross-linking process (Figure 1). In this case, hydrogen atoms are separated from the polyethylene chains, and the carbon elements between adjacent polymer chains can establish a connection between the two polymer chains. The higher the number of connections along the chain will be established, the higher the cross-linking rate will be. With an increased cross-linking rate, the material usually gets more rigid. One key benefit for heat-shrink products is this cross-linking effect in the material that causes these products to lose their melting properties. Products can now be heated to temperatures beyond the crystalline melting point without melting. Above this temperature, heat-shrink products such as extruded tubes or molded parts (breakouts and end caps) can be expanded and formed in shape and remain in this position. In contrast, the temperature will decrease below the crystalline melting point again. FIGURE 1: Cross-slinking process. (TE Connectivity)