Polyethylene-Matrix Composites with Halloysite Nanotubes with Enhanced Physical/Thermal Properties

Area of Science:

• Materials Science
• Polymer Science
• Nanotechnology

Background:

• Low-density polyethylene (LDPE) is a widely used thermoplastic known for its flexibility.
• Enhancing the mechanical properties of LDPE is crucial for expanding its applications.
• Halloysite nanotubes (HNT) offer potential as reinforcing fillers due to their unique structure and properties.

Purpose of the Study:

• To investigate the impact of varying halloysite nanotube (HNT) concentrations on the mechanical and thermal properties of LDPE composites.
• To evaluate the role of maleic anhydride-grafted PE (PE-graft-MA) as a compatibilizer in the LDPE/HNT system.
• To determine the optimal HNT content for reinforcing LDPE without significant loss of desirable properties.

Main Methods:

• Polyethylene nanocomposites were fabricated using injection molding with varying HNT content (0-6 wt%) and a fixed PE-graft-MA content (5 wt%).
• Mechanical properties assessed include ultimate tensile stress, strain at ultimate stress, hardness, and impact strength.
• Thermal properties evaluated encompass heat deflection temperature (HDT), Vicat softening temperature, and melt flow rate (MFR).

Main Results:

• Addition of HNT significantly increased heat deflection temperature (up to 47 °C) and ultimate tensile strength (up to 16.00 MPa).
• Slight decreases were observed in Vicat softening temperature, strain at ultimate stress, impact strength, and hardness.
• Melt flow rate (MFR) deteriorated significantly, nearly doubling, indicating processing challenges.

Conclusions:

• Halloysite nanotubes can effectively reinforce LDPE at low filler loadings, improving thermal and tensile properties.
• Superb dispersion of HNT within the polyethylene matrix is essential for achieving reinforcement without compromising ductility.
• The use of PE-graft-MA aids in the dispersion and compatibility of HNT in the LDPE matrix.