High-Temperature Performance Enhancement of Bitumen by Waste PET-Derived Polyurethane

Abstract

Bitumen performance enhancement through modification by reactive polymers gained significant attention in the road construction industry. Polymeric bitumen additives, such as polyurethane, improve bitumen properties at low and high in-service temperatures. This research aimed to increase the polymer content (polyurethane) from 3% to 5%wt of bitumen by introducing cross-linking agent, sulfur. Synthesis of polyurethane was via in situ polymerization of bis (2-hydroxyethyl) terephthalamide (BHETA) in the presence of bitumen with sulfur as a cross-linking agent. BHETA was produced from polyethylene terephthalate (PET) by an aminolysis reaction. Penetration and softening point, frequency sweep test, performance grade (PG) and multiple stress creep recovery (MSCR) were evaluated to compare base and modified bitumen. Results show that the penetration and softening point of modified binders were reduced and increased, respectively, the frequency sweep test indicated improvement in viscoelastic properties of modified bitumen, PG of base bitumen was enhanced by two grades, i.e., from 58°C to 70°C, and the nonrecoverable creep compliance was increased by 81.82% at polymer content of 4% and sulfur content of 0.2%. The FTIR spectra of modified bitumen confirmed the formation of urethane linkages. Therefore, aminolysis of waste PET and in-situ polymerization to produce polyurethane can be applied to improve the performance of bitumen at high temperatures.

Anion Exchange Membranes Based on Chemical Modification of Recycled PET Bottles

“…The C–O stretching vibration of the ester group was observed at 1020, 1093, and 1240 cm –1 . , The C–C stretching vibration of the ring was detected at 1340 and 1408 cm –1 . Medium peaks at 1503 and 1588 cm –1 were attributed to the CC aromatic ring . Lastly, a strong stretching vibration at 1714 cm –1 corresponded to the carbonyl group (CO) .…”

“…This interaction decreases the polarity of the carbonyl group, resulting in a downshift of the peak. Additionally, the N–H stretching vibration of the amine group in PET-B was detected at 1539 and 3303 cm –1 , 37 , 41 while peaks at 692, 819, 1165,1283, 1313, and 1540 cm –1 correspond to the C–N stretching vibration, 7 , 42 , 43 indicating the successful modification of PET-B. The use of recycled PET bottles with their inherent chemical structure of the polymer proves to be a viable and effective approach for incorporating ion exchange functional groups.…”

“… 36 Medium peaks at 1503 and 1588 cm –1 were attributed to the C=C aromatic ring. 37 Lastly, a strong stretching vibration at 1714 cm –1 corresponded to the carbonyl group (C=O). 38 The modification of PET by ethylene glycol revealed the presence of a new functional group, particularly the hydroxyl group observed at 3439 cm –1 .…”

Nanoclays as fillers for performance enhancement in building and construction industries: State of the art and future trends

“…Improvements in the pavement sector, including heavy axle design, traffic leveling, huge truckloads, and environmental requirements, necessitated the need for asphalt binders to be improved [130]. Polymer modification has become increasingly popular in recent decades as a means of enhancing asphalt pavement's high-temperature performance [131] without compromising its low-temperature behavior. One of the technique to improve high-temperature performance is using nanoclays as a reinforcement [130,132,133].…”

Smart Asphalt Mixtures: A Bibliometric Analysis of the Research Trends

“…The binder can be made of asphalt, being called asphalt binder. It is typically made up of bitumen or asphalt but can also include additives or modifiers to enhance its performance and properties [69]. Thus, the asphalt binder provides cohesion, strength, and durability to the asphalt pavement [70].…”