Copolymerization of a Bisphenol a Derivative and Elemental Sulfur by the RASP Process

Abstract

Fossil fuel refining produces over 70 Mt of excess sulfur annually from for which there is currently no practical use. Recently, methods to convert waste sulfur to recyclable and biodegradable polymers have been delineated. In this report, a commercial bisphenol A (BPA) derivative, 2,2′,5,5′-tetrabromo(bisphenol A) (Br4BPA), is explored as a potential organic monomer for copolymerization with elemental sulfur by RASP (radical-induced aryl halide-sulfur polymerization). Resultant copolymers, BASx (x = wt% sulfur in the monomer feed, screened for values of 80, 85, 90, and 95) were characterized by thermogravimetric analysis, differential scanning calorimetry, and dynamic mechanical analysis. Analysis of early stage reaction products and depolymerization products support proposed S–Caryl bond formation and regiochemistry, while fractionation of BASx reveals a sulfur rank of 3–6. Copolymers having less organic cross-linker (5 or 10 wt%) in the monomer feed were thermoplastics, whereas thermosets were accomplished when 15 or 20 wt% of organic cross-linker was used. The flexural strengths of the thermally processable samples (>3.4 MPa and >4.7 for BAS95 and BAS90, respectively) were quite high compared to those of familiar building materials such as portland cement (3.7 MPa). Furthermore, copolymer BAS90 proved quite resistant to degradation by oxidizing organic acid, maintaining its full flexural strength after soaking in 0.5 M H2SO4 for 24 h. BAS90 could also be remelted and recast into shapes over many cycles without any loss of mechanical strength. This study on the effect of monomer ratio on properties of materials prepared by RASP of small molecular aryl halides confirms that highly cross-linked materials with varying physical and mechanical properties can be accessed by this protocol. This work is also an important step towards potentially upcycling BPA from plastic degradation and sulfur from fossil fuel refining.

Durable composites by vulcanization of oleyl-esterified lignin

“…60 Similar thermogravimetric features are displayed by the decomposition of other HSMs comprising highly aromatic organic monomers. 7,8,33,34,53…”

“…This route has been used to prepare durable composite GS80 from guaiacol (Scheme 1B) as well as several HSMs from bisphenol A derivatives. 33,34,52,53 At sufficiently low crosslink densities, most HSMs produced by these processes can be recycled by simple melt-casting, owing to the thermal reversibility of S-S bond breakage/formation. [54][55][56][57][58][59] Kra (alkali) lignin like that used in the current work has a complex structure (Fig.…”

High strength composites from low-value animal coproducts and industrial waste sulfur

“…Most HSMs have been prepared by inverse vulcanization (Scheme 1), [1][2][3][4][5][6] although a few alternate methods for their synthesis and processing involving alternate chemical pathways have recently emerged as well. 36,[39][40][41][42][43][44][45][46] Inverse vulcanization relies on the reaction of olens with thermally generated sulfur radicals. A wide range of olens serve as viable comonomers in inverse vulcanization, including numerous bio-derived examples such as limonene, modied cellulose or lignin, nely ground peanut shells, and plant-derived terpenoid alcohols like citronellol, geraniol and farnesol.…”

Inverse vulcanization of octenyl succinate-modified corn starch as a route to biopolymer–sulfur composites

“…[27][28][29][30][31] Similar HSMs can be prepared from the reaction of aryl halides or anisole derivatives with sulfur as well, although polymerization of these monomers proceeds via different mechanisms than simple inverse vulcanization. [32][33][34][35] In addition to the aforementioned applications of HSMs, our group has recently reported numerous high-strength composite materials prepared by the reaction of sulfur with bio-derived monomers including fatty acids, [36][37][38][39] triglycerides, 42 terpenoids, 21,43 amino acid derivatives, 44 lignin derivatives, 22,35,45,46 cellulose derivatives, 3,21 and raw lignocellulosic biomass sources. 40,41 In terms of commercialization of biopolymer-derived materials, starch-derived films and composites have recently gained tremendous interest because starch is remarkably simple to solubilize, derivatize and process compared to cellulose.…”