How does the absence of cross-linking in elastomers affect their behavior?

The absence of cross-linking in elastomers significantly affects their behavior by allowing them to flow more freely, similar to liquids. Cross-linking creates bonds between the polymer chains, giving elastomers their characteristic elasticity and structural integrity. When there is no cross-linking, the polymer chains are more independent and can move past one another more easily. This lack of restraint enables the material to deform and flow under stress, resulting in a behavior akin to that of liquids.

In cross-linked elastomers, the material is held together more firmly, which prevents it from flowing and maintains its shape under various conditions. The absence of cross-links means that as force is applied, the chains can separate and slide, leading to fluid-like movement. This is why the correct answer is that elastomers without cross-linking can exhibit a flowing behavior, akin to that of liquids.