Which type of polymers have a strong 3-D structure due to rigid cross-links?

Thermosetting polymers possess a strong three-dimensional structure due to the presence of rigid cross-links formed during the curing or hardening process. When these materials are heated and cured, they undergo a chemical reaction that creates bonds between the polymer chains, which leads to a network structure. This rigid structure contributes to their durability, heat resistance, and ability to maintain shape under stress.

In contrast, thermoplastic polymers do not have these cross-links and can be remolded and reshaped when heated. Linear polymers consist of long, straight chains and may offer some flexibility but lack the cross-linking necessary for the rigid structure found in thermosets. Elastomeric polymers, while they can be networked to some extent, primarily excel in flexibility and stretchability rather than in structural rigidity. Hence, thermosetting polymers are the ones characterized by their strong, durable connections that define their three-dimensional structure.