Effect of transesterification degree and post-treatment on the in-service performance of NCO-functionalized vegetable oil bituminous products

Abstract

The bitumen modification through polyurethane prepolymers presents significant benefits for the manufacture of bituminous products for the paving industry. In this sense, this work explores the use, as bitumen modifier, of a novel reactive prepolymer synthesized by reaction of 4,4´,diphenylmethane diisocyanate (MDI) and a vegetable oil-based polyol, castor oil (CO), previously transesterified with pentaerythritol. On the one hand, thermal analysis on transesterified CO revealed a highly stable prepolymer, making it suitable to be used for bitumen modification in a wide range of processing temperatures, 90-180 ºC. On the other hand, the bitumen modification achieved for the polyurethane-modified strongly depends on the transesterification degree and posttreatment procedures involved. In this sense, Atomic Force Microscopy (AFM) proved that MDI-prepolymers, based on castor oil transesterified with 4 wt.% pentaerythritol, lead to modified samples with a more complex microstructure which enhances rheological properties and reduces thermal susceptibility. In any case, viscoelastic and flow tests showed that the addition of small quantities of this reactive prepolymer to bitumen leads to products with enhanced performance at high in-service temperatures.

Rheology of lignin-based chemical oleogels prepared using diisocyanate crosslinkers: Effect of the diisocyanate and curing kinetics

“…On the other hand, diisocyanates (HDI, IDI, TDI, MDI…) are capable of reacting with -OH groups of many polymers, e.g. butanediol polyester [14], hydroxyl-terminated polybutadiene and butacene [15], 4,4'-{oxy-1,4-diphenyl bis(nitromethylidine)}diphenol [16], glycidyl azide polymer [17], as well as graphene oxide [18] and mineral [19] and castor oils [20,21], to form urethane linkages (-NH-C(O)-O-) owing to protons be transferred from -OH to the N in -NCO groups. These compounds are known to form materials with a wide variety of outstanding properties, depending on the application.…”

Research on Micro-Mechanics Modelling of TPU-Modified Asphalt Mastic

“…Thermoplastic Polyurethane Elastomer (TPU) is a new polymer material, which has been widely used in many fields due to its flexible formulation and wide range of adjustable properties [1][2][3][4][5]. However, the research into and application of TPU as an asphalt modifier in the field of road engineering are rarely reported [6]. The ability of TPU-modified asphalt to interact with the mineral powder determines the road engineering properties of the TPU-modified asphalt mix based on the results of extensive experimental trials.…”

Evaluation and mechanism of interaction effect between thermoplastic polyurethane elastomer modified asphalt and fillers

“…Thermoplastic polyurethane (TPU) elastomer as a new polymer material, which has been widely used in many fields due to its flexible formulation and wide adjustable range of properties. [2][3][4][5][6] However, the research and application of TPU as asphalt modifier in the field of road engineering are rarely reported. 7 The study of TPU as modifier of asphalt not only should be focused on the single material and the mixing ratio, but also should take the interface phase between heterogeneous materials which is difficult to capture, complex, and changeable as the research object.…”

“…Thermoplastic polyurethane (TPU) elastomer as a new polymer material, which has been widely used in many fields due to its flexible formulation and wide adjustable range of properties 2–6 . However, the research and application of TPU as asphalt modifier in the field of road engineering are rarely reported 7 .…”