Eco-Friendly Redemption of Butyl Rubber in Cost Efficient Ablative Composites for Aerospace Applications

Abstract

Disposal management of waste, discarded and unserviceable Butyl Rubber (BR) is a matter of environmental concern which requires immediate attention. Wastage of expensive rubber which is used in all types of rubber gaskets, seals and hoses, should be recycled and reused for reclamation of the rubber raw materials. The present study proposes novel, ecological and prudent heat resistant hybrid composites of Resorcinol Formaldehyde (RF) and waste BR, fabricated through in-situ polymerization and tested under oxyacetylene flame at 2300 C for 60 s for ablative properties. The composite exhibits high ablation resistance, quantified by a drop of Mass Ablation Rate from 0.079 for pristine RF to 0.068 compared to pristine resin due to increase in the formation and retention of insulative turbostratic char. Thermogravimetric Analysis (TGA) reveals the degradation traits with a 13% enhanced char residue up to 800 C. These composites pose competition with respect to cost effective heat shields as Thermal Protection Systems (TPS) in re-entry vehicles and space shuttles and fire proofing materials.

Ionic‐liquid‐assisted three‐dimensional caged silica ablative nanocomposites

“…Hence, there is strong motivation to fully understand the behavior of RF‐resin‐based composites under extreme thermal conditions for specific defense and engineering applications because the knowledge of this behavior is currently insufficient. A literature review showed us that majority of the works in phenolics have mainly been focused on conventional PF systems, and limited literature on the ablative performance of RF resin is available, wherein RF modification with various compositions of ultra‐high‐temperature ceramics (SiC) and a wide range of additives (boric acid, OP‐POSS, carbon soot, butyl rubber, fly ash cenospheres, and boron nitride) has been studied …”

“…In OP‐POSS–RF composites modified with different weight percentages of OP‐POSS, the high bond dissociation energy of the polymeric matrix and the uniform interconnected network of nanospheres significantly reduced the flow of oxygen into the substrate material. The ablative properties of RF were also marginally improved when it was modified with butyl rubber …”

“…The aim of this study was to elucidate the interfacial chemistry and related structure–property relationship issues for tailoring FS–RF interfacial interactions with enhanced thermal ablative properties to allow these materials to be used in thermal ablative applications where the containment and suppression of high‐thermal‐heat‐flux threats to humans, equipment, and structures is of paramount importance . A layer of silica–RF nanocomposite with superior ablative properties formed a turbostratic carbonaceous char in the high‐thermal‐flux environs to prevent the resulting heat flux from reaching the substrate with a positive effect on the flame retardancy . The efficacy of the ablative thermal barrier coating was also deliberated in our recent review articles on thermal barrier coatings …”

Nanoencapsulated Core and Shell Electrospun Fibers of Resorcinol Formaldehyde

“…Therefore, unlike other systems, it has been established that untreated systems of phenolic resin show a greater specific cooling capacity [57], with adsorption selectivity of ethanol or methanol molecules over water. Due to the increase in the curing and aromaticity in case of resorcinol formaldehyde as compared to conventional phenolics [20][21][22][23][24], the ratio of sp 2 -hybridized carbon atoms with respect to the total number of carbon atoms increase. Water adsorption occurs on the sp 2 -hybridized carbon basal planes by weak dispersion force, thereby 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 forcing the molecules to be adsorbed on carbon planes containing sp 3 -hybridized carbon [58][59][60].…”

“…Apart from the propitious features of phenolic precursors high carbon yield, good dimensional stability and low cost, abundance of micropores produced after carbonization is an added advantage [19]. However, with reference to our earlier published work, phenol formaldehyde has been replaced by resorcinol formaldehyde, in applications involving requirement of high carbon yield, which also requires lower polymerization and curing times [20][21][22][23] hence, the articulate consequence of replacing phenolic resins could be the formation of 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 high quality Carbon fibers on carbonization, by the virtue of high dimensional stability, high carbon yield and low cost of the resin [24].…”