The Influence Of Polymer Structure On The Performance Of Modified Asphalt

The structure of polymer is an important factor to the performance of modified asphalt. The polymer modified asphalts (PMA) were prepared using a twin-screw extruder. Two kinds of asphalt with different components were mixed with two SBS polymers and three PE polymers at four polymer contents. The binders were subjected to fluorescent microscopy and Fourier transform infrared (FTIR) spectroscopy besides of conventional analysis such as softening point, ductility and penetration.The results of the investigation indicated that the addition of SBS and stabilizer initiated the cross-linking reaction between SBS as well as SBS and asphalt to form a network. As a result, the performances of asphalt at both high and low temperature and stability at high temperature were improved greatly. And the performances of R-SBS PMA were superior to those of L-SBS PMA because of the particular structure of R-SBS molecule.By grafting some functional groups (GMA and MAH) to LDPE, both GMA-g-LDPE and MAH-g-LDPE improved the performance of high temperature and temperature-susceptibility compared with LDPE. However, GMA-g-LDPE also improved the performance of low temperature and stability at high temperature while MAH-g-LDPE could not because of self-crosslinking. FTIR indicated that there was no peak change when LDPE was mixed with asphalt, while the epoxy group of GMA-g-LDPE and carboxylic acid anhydride of MAH-g-LDPE disappeared.