Polymer morphology significantly influences the properties of polymers like polyethylene. High-density polyethylene (HDPE) is characterized by its __________ structure, which contributes to its strength and rigidity compared to low-density polyethylene (LDPE).

High-density polyethylene (HDPE) is characterized by its highly crystalline, tightly packed linear structure, which means its chains are straight and run close together. Because the chains are almost perfectly aligned, the material can form many strong intermolecular bonds. These bonds give HDPE a higher modulus of elasticity, making it stiffer and stronger than the more branched, less crystalline low‑density polyethylene. For example, a 10‑mm HDPE rod can bend only a few millimeters under load, while a similarly sized LDPE rod might buckle more easily. This difference in packing explains why HDPE is used for pipes and bottles that need to hold pressure, whereas LDPE is chosen for flexible packaging.