Bitumen Binders Modified with Sulfur/Organic Copolymers.

Jakub Wręczycki,Rafał Anyszka,Tomasz Gozdek,Volodymyr Gunka,Michael Bratychak,Dariusz M Bieliński,Yuriy Demchuk

doi:10.3390/ma15051774

Jakub Wręczycki, Rafał Anyszka + Show 5 more

Open Access

https://doi.org/10.3390/ma15051774

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Abstract

With the continuing growth of waste sulfur production from the petroleum industry processes, its utilization for the production of useful, low-cost, and environmentally beneficial materials is of primary interest. Elemental sulfur has a significant and established history in the modification of bitumen binders, while the sulfur-containing high-molecular compounds are limited in this field. Herein, we report a novel possibility to utilize the sulfur/organic copolymers obtained via the inverse vulcanization process as modifiers for bitumen binders. Synthesis and thermal characterization (TGA-DSC) of polysulfides derived from elemental sulfur (S8) and unsaturated organic species (dicyclopentadiene, styrene, and limonene) have been carried out. The performance of modified bitumen binders has been studied by several mechanical measurements (softening point, ductility, penetration at 25 °C, frass breaking point, adhesion to glass and gravel) and compared to the unmodified bitumen from the perspective of normalized requirements concerning polymer-modified bitumen. The interaction of bitumen binder with sulfur/organic modifier has been studied by means of FTIR spectroscopy and DSC measurements. The impact of the modification on the performance properties of bitumen has been demonstrated. The bitumen binders modified with sulfur/organic copolymers are in general less sensitive to higher temperatures (higher softening point up to 7 °C), more resistant to permanent deformations (lower penetration depth), and more resistant to aging processes without intrusive deterioration of parameters at lower temperatures. What is more, the modification resulted in significantly higher adhesion of bitumen binders to both glass (from 25% up to 87%) and gravel surfaces in combination with a lower tendency to form permanent deformations (more elastic behavior of the modified materials).

Highlights

The utilization of sulfur excess, mainly manufactured as a side product of the petroleum industry processes, constitutes an important and challenging problem for the chemical industry and related branches [1,2]
In order to fulfill this research gap as well as encourage by successful application of sulfur/organic copolymers obtained via the “inverse vulcanization” process as curing agents for rubber in our previous work [32], we report the application of selected polysulfides of this type as modifiers for bitumen binder
The presented study showed that the sulfur/organic copolymers obtained by the facile method so-called “inverse vulcanization” can be potentially applied as modifiers for bitumen binders

Summary

Introduction

The utilization of sulfur excess, mainly manufactured as a side product of the petroleum industry processes, constitutes an important and challenging problem for the chemical industry and related branches [1,2]. Exploration of low-cost, high-sulfur content organic or polymeric materials fabricated from elemental sulfur (S8 ) and its further utilization pathways should be of primary interest to sustain the proper cycle of sulfur conversion [2,3]. The addition of high-molecular materials to a raw bitumen binder constitutes a very promising trend in the modification of its properties nowadays. Various polymers have been utilized over the years as bitumen binder modifiers with an example of thermoplastic polymers (polyethylene [11], polypropylene [12], ethylene vinyl acetate or ethylene butyl acrylate [13]), thermoplastic elastomers (styrene-butadiene-styrene triblock copolymers (SBS) [13,14]), polycondensation resins (phenol-cresol-formaldehyde resins and phenol-formaldehyde resins with labile peroxy bonds or methacrylic components [10,15]), petroleum resins with epoxy, hydroxy or carboxy groups [16], low-molecular organic compounds (formaldehyde and maleic anhydride) [17,18], or recycled elastomers in the form of ground tire rubber [19]

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