摘要 |
<p>Silane is grafted upon polymer molecules and the material is shaped (e.g., extruded or injection-molded) and caused to cross-link. Both steps must be completed before expanding (following reheating, if necessary) and cooling the object at the expanded state. Cap- and sleeve-making is disclosed, including internal as well as external exposure to water for cross-linking, possibly combined with the requisite preheating for the expansion.</p> |