Durable, acid-resistant copolymers from industrial by-product sulfur and microbially-produced tyrosine

Abstract

Copolymers of waste sulfur and bacterially-produced tyrosine are reported.

Valorization of Lignin as a Sustainable Component of Structural Materials and Composites: Advances from 2011 to 2019

“…Although elemental sulfur itself is quite brittle, durable materials can be obtained for the copolymers comprising up to 90 wt.% sulfur [51][52][53][54]. These efforts have employed a wide range of starting materials including cellulose, lignin, amino acids, terpenoids, algae acids, polystyrene derivatives, and other olefins [55][56][57][58][59][60][61][62][63][64][65][66][67][68][69][70]. More recently, radical-induced aryl halide/sulfur polymerization (RASP) proved similarly effective for preparation of high sulfur-content materials (HSMs) but employing aryl halides in place of the olefins required for inverse vulcanization.…”

Sequential crosslinking for mechanical property development in high sulfur content composites

“…High sulfur-content materials (HSMs) can be conveniently prepared by the reaction of elemental sulfur with olefins by inverse vulcanization (InV) [1][2][3] or from aryl halides by radical-induced aryl halide-sulfur polymerization (RASP, Scheme 1). [4][5][6] HSMs produced by these routes have been proposed for applications such as electrode materials, [7][8][9][10][11][12] lenses for thermal imaging, [13] fertilizers [14,15] absorbents for removing toxins from water, [16][17][18][19][20][21] or as structural materials [22][23][24][25][26][27][28][29] and thermal insulators. [30,31] The InV mechanism proceeds when olefins are crosslinked by their reaction with sulfur radicals produced by heating elemental sulfur to >159 C. RASP involves thermal reaction of aryl halides with elemental sulfur whereby S C aryl bonds are formed, a process requiring slightly higher temperatures of 220-250 C.…”

Copolymers by Inverse Vulcanization of Sulfur with Pure or Technical‐Grade Unsaturated Fatty Acids

“…This behavior is likely attributable to the presence of linolenic acid, a triply unsaturated fatty acid, in the technical‐grade sample, thus providing increased crosslink density in the ZLS x samples. Although linolenic acid is a minor component (~1%), it has been demonstrated that even 1% of a monounsaturated crosslinking agent can increase the T d of a composite by 20–40°C …”

“…The lower wt % sulfur composites ( ZPLS 85 and below and ZLS 90 and below) were not remeltable due to the increased crosslinking, and thus were not able to be cast into molds for DMA analysis. As the wt % of sulfur in the composites decreases, the storage modulus increases, as the higher percentage of organic material in the composite contains a higher number of double bonds and can stabilize the chains of sulfur crosslinking the material …”

“…Although extended sulfur catenates are generally unstable with respect to the orthorhombic (S 8 ring) allotrope at STP (standard temperature and pressure), such extended chains can be stabilized by their confinement within the crosslinked network structure. In this way, stable sulfur catenates averaging from five to over 100 sulfur atoms have been observed, depending on the composition and crosslink density of the network in which the chains are confined . The high crosslink density and extended sulfur catenates present in inversely vulcanized materials, coupled with the thermal reversibility of SS bond formation, have led to materials that can be mechanically strong, recyclable by simple remelt–recast processes, and thermally healable.…”