Polyethylene - Low Density (LDPE) - Material Information

Low-Density Polyethylene (LDPE) is a semi-crystalline thermoplastic widely used for its toughness, ductility, and chemical resistance. Produced via high-pressure free-radical polymerization, LDPE is characterized by significant chain branching, which gives it low crystallinity (~40%), low density (0.910–0.940 g/cm³), and high flexibility compared to linear polyethylene grades. Its low stiffness and high impact resistance make it suitable for film extrusion, wire insulation, and flexible containers.

Material Overview

LDPE exhibits a melting point around 110 °C and a glass transition temperature of ?110 °C. It has a tensile strength of 8–12 MPa, elongation at break up to 600%, and thermal conductivity of approximately 0.33 W/m·K. The polymer’s amorphous regions enable flexibility even at sub-zero temperatures, while its crystalline lamellae contribute to moderate rigidity and strength. LDPE is chemically inert to most acids, alcohols, and bases but swells in hydrocarbons and aromatic solvents.

Recent studies have expanded LDPE’s performance envelope through nanocomposite and recycling strategies. Awad (2021) demonstrated that the inclusion of nanoclay (2–6 wt%) significantly improves LDPE’s tensile strength and thermal stability, with optimized dispersion enhancing crystallinity and heat deflection temperature. Esmaeilzade et al. (2024) investigated circular economy approaches, showing that recycled LDPE–LLDPE blends maintain comparable mechanical and rheological properties to virgin materials while reducing waste. In a related work, Al-Attar et al. (2018) found that LDPE/LLDPE blends exhibit synergistic effects, where a 50:50 composition yields the highest tensile strength and balanced melt rheology suitable for packaging applications. LDPE also retains electrical insulation integrity under moderate thermal stress, as shown by Hedir et al. (2019), who reported minimal dielectric loss up to 80 °C.

Exposure to ultraviolet radiation and thermal oxidation can induce surface embrittlement and color change, yet the addition of stabilizers or copolymerization with ethylene–vinyl acetate (EVA) or polypropylene can enhance long-term performance (Tikr?t Journal for Pure Science, 2023).

Applications and Advantages

LDPE’s combination of flexibility, toughness, and chemical inertness makes it ideal for films, tubing, containers, and wire insulation. It is also used in biomedical packaging, corrosion protection, and as a matrix in polymer composites. Its low dielectric constant and high resistivity enable effective use in electrical applications, while its resistance to environmental stress cracking supports extended outdoor usage when stabilized with UV inhibitors.

Goodfellow Availability

Goodfellow offers LDPE in film, rod, sheet, and tube forms, with customizable thicknesses and purity levels for research and industrial applications. Explore the full range of LDPE and polyethylene variants through the Goodfellow product finder.

References

• Esmaeilzade, R., Jandaghian, M. H., Rokni Hosseini, L. S., & Zarghampour, S. (2024). Correlation of structure, rheological, thermal, mechanical, and optical properties in LDPE/LLDPE blends in the presence of recycled LDPE and LLDPE. Polymer Engineering & Science. https://doi.org/10.1002/pen.26614
• Al-Attar, F., Alsamhan, M., Al-Banna, A., Samuel, J., & Kuwait, C. (2018). Thermal, mechanical, and rheological properties of LDPE/LLDPE blends for packaging applications. Journal of Materials Science and Chemical Engineering, 6(1), 45–54. https://doi.org/10.4236/MSCE.2018.61005
• Awad, S. A. (2021). Mechanical and thermal characterization of LDPE/nanoclay composites. Polymers & Polymer Composites, 29(8), 961–972. https://doi.org/10.1177/0967391120968441
• Hedir, A., Slimani, F., Moudoud, M., Bellabas, F., & Loucif, A. (2019). Impact of thermal constraint on the properties of low-density polyethylene. In Advances in Materials Research (pp. 1157–1164). Springer. https://doi.org/10.1007/978-3-030-31680-8_92
• Tikr?t Journal for Pure Science (2023). The effect of UV radiation on the thermal and mechanical properties of PP/LDPE blends. TJPS, 21(1). https://doi.org/10.25130/tjps.v21i1.952