Influence of Titanium Dioxide Content on the Crystallization Behavior and Solar Reflectance of Polyethylene/Titanium Dioxide Composites

Abstract

Titanium dioxide (TiO₂) particles were introduced to improve the solar reflectance of high-density polyethylene (HDPE). The organic-inorganic hybrids were fabricated by melt blending. A series of characterizations were taken to study the crystallization behavior, morphology, solar reflectance, and real cooling property. TiO₂ particles acted as nucleation agents in the HDPE matrix and made the HDPE form thick lamellar crystals. TiO₂ particles could disperse well into the HDPE matrix under 2.5 wt.% loading but agglomerated with 3 wt.%. Solar reflectance was related to the reflective index of TiO₂ and the microstructure of HDPE. The real cooling property depended on the solar reflectance and the dispersion of the TiO₂ particles in the HDPE matrix.

Keywords:

• Cooling materials
• Polyethylene
• Solar reflectance
• Titanium dioxide

Notes

T _c = peak crystallization temperature, T _m  = peak melting temperature, ΔH _m  = melting enthalphy, X _c  = degree of crystallinity.

U, V, and N represent the reflectance for the ultraviolet, visible, and infrared bands respectively, and S is the irradiance-weighted average values of solar reflectance.^{[ 7 ]}

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