Inverse Vulcanization Polymers with Enhanced Thermal Properties via Divinylbenzene Homopolymerization-Assisted Cross-Linking

Abstract

High-refractive-index sulfur-rich polymers with significantly improved thermal properties are prepared using divinylbenzene (DVB) as a comonomer in a modified, lowtemperature inverse vulcanization with elemental sulfur. Differential scanning calorimetry and Fourier transform infrared studies reveal that under the modified inverse vulcanization conditions, homopolymerized DVB segments form, leading to high glass-transition temperatures (T g > 100 °C) and thermal stability previously unattainable from the inverse vulcanization of bifunctional olefin comonomers. On the basis of the modified procedures, a three-step molding process of the inverse vulcanization product of DVB, poly(S-r-DVB), involving (1) prepolymer formation, (2) hot-press compression molding of the soft prepolymer, and (3) thermal annealing of the molded product is demonstrated. The molded high-sulfur-content poly(S-r-DVB) exhibits a high refractive index (n > 1.85), along with high midwave infrared transmittance. Combined with a high T g , these properties render poly(S-r-DVB) with properties highly desirable in applications involving infrared optics.

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.…”

Scalable High Refractive Index polystyrene-sulfur nanocomposites via in situ inverse vulcanization

“…More recently, Kleine, et al, developed chalcogenide hybrid inorganic/organic polymers with enhanced long-wave infrared (LWIR) spectrum (7-14 µm), this low organic content terpolymers showed superior IR transparence and demonstrated the ability to take highly resolved thermal images in near or complete dark environment 32,33 . Similar chemistry of introducing S-S bond in the copolymer to improve the refractive index was later adopted by many researchers are prepared various HRI copolymers [34][35][36][37][38] .…”

Polymers Made by Inverse Vulcanization for Use as Mercury Sorbents

“…The mechanism of the inverse vulcanization reaction has not been fully elucidated and it may vary depending on the reaction conditions, the organic crosslinker, [24][25][26] or the use of a catalyst or accelerator. 27 Nevertheless, one mechanism by which the process might occur is as follows: First, elemental sulfur is melted and heated to a sufficiently high temperature to provoke ringopening polymerization via a radical mechanism.…”

“…14 In this way, inverse vulcanization provides polysulfide-rich materials that are distinct from other classes of carbon-based polymers in their chemical reactivity and their physical and optical properties (Figure 1). [20][21][22][23] The mechanism of the inverse vulcanization reaction has not been fully elucidated and it may vary depending on the reaction conditions, the organic crosslinker, [24][25][26] or the use of a catalyst or accelerator. 27 Nevertheless, one mechanism by which the process might occur is as follows: first, elemental sulfur is melted and heated to a sufficiently high temperature to provoke ring-opening polymerization via a radical mechanism.…”