Journal of Applied Polymer Science, Vol.127, No.1, 67-78, 2013
Polymer-modified bitumen of recycled LDPE and maleated bitumen
Maleated bitumen was prepared by the reaction of penetration grade bitumen (80/100) with maleic anhydride at 150 degrees C for 2 h under nitrogen atmosphere. The effectiveness of maleation was assessed in bitumenrecycled low-density polyethylene (LDPE) blends in terms of their softening point and elastic recovery. It was observed that the softening point and elastic recovery of the blends increased after maleation of the base bitumen owing to the formation of an asphaltene-linked-LDPE system. To obtain the desired elasticity, a recoverable composition was worked out with the help of maleated bitumen, recycled LDPE and styrenebutadienestyrene. The storage stability of the blends was assessed in terms of their difference in softening points, rheological parameters, and microstructure of the top and bottom portions of test tube samples. The difference in softening point of the recoverable maleated bitumen blend was 5 degrees C as compared to 60 degrees C for the base bitumen blend. The phase angle was also reduced to 7.4 degrees at 70 degrees C compared with the 44.30 degrees for the base bitumen blend. Scanning electron micrographs indicate that polymers existed in both the top and the bottom portions of the aged test tube maleated blend samples. The stability of the blend was further improved when LDPE is colloidal milled with maleic anhydride in the blend preparation. Roofing bitumen was also made with maleated bitumen containing 9 wt % recycled LDPE content. Based on the rheological data, it was found that the maleated bitumenLDPE blend exhibited superior time-/temperature-dependent response and higher creep recovery compared with the base bitumen blend. (C) 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2012