Preparation and Properties of Bitumen-Modified Polyurethane Solid–Solid Phase Change Materials

Abstract

This study aimed to evaluate the potential use of polyurethane solid–solid phase change material (PUSSPCM) as polymer modifier in asphalt binder. PUSSPCMs were synthesized via the two-step condensation reaction of 4,4′–diphenylmethane diisocyanate, polyethylene glycol, and 4,4′-methylenebis(2-chloroaniline). The synthesized PUSSPCMs possessed suitable transition temperature in the range of 10.9°C to 46.8°C and high latent heat enthalpy in the range of 71.68 to 73.87 J/g. The synthesized PUSSPCMs possessed good thermal stability even at 320°C. Furthermore, varying amounts of PUSSPCM modifiers were added to a neat asphalt binder. The viscosity of all the modified bitumen samples was lower than 2,000 cP. The addition of the PUSSPCMs did not greatly affect the penetration, softening point, and storage stability of modified asphalt. However, excessive content of PUSSPCMs adversely affected the ductility of modified asphalt. The temperature change rate of the PUSSPCM modified asphalt decreased with increasing PUSSPCM content. When the content of PUSSPCMs reached 7% by weight, the maximum temperature difference of neat bitumen specimen and modified bitumen specimen reached about 9.0°C in the laboratory.