(Bad Sobernheim, Germany) has developed radiation-crosslinkable grades of polyamide, in the form of its TechnoMid PA6 VN and PA 66 VN grades. These incorporate a crosslinking additive which the compounder says brings a number of benefits to the nylon, among them improving a part’s temperature resistance and glow wire resistance. According to the compounder, the material's flame-resistance and its ability to withstand chemical attack, aging and stress-cracking increase significantly. The radiation-crosslinkable compounds can be injection molded as with any standard PA. Unlike reactive crosslinking agents, these crosslinking additives are not temperature sensitive, so the compound's cooling and shrinkage behavior are not affected by the crosslinking additive.
Radiation crosslinking functions independently of the presence of reinforcing materials such as glass fibers, or functional additives such as magnetite. In trials witnessed by MPW, a radiation-crosslinked demonstration molding— in this case, a manifold from a car exhaust system—was exposed for five seconds to a soldering iron’s tip which had been heated to 350°C. The resulting penetration depth was less than 0.5 mm; on a non-crosslinked part, the penetration depth was greater than 3 mm. —[email protected]