Thermomechanical devulcanization of butyl rubber (BR1), bromobutyl rubber (BR2) vulcanizates, both prepared in laboratory, and a waste commercial butyl rubber (BR3) using a twin-screw extruder is reported. The commercial butyl rubber vulcanizate (BR3) was used as a tire curing bladder and the waste rubber received from a tire manufacturing company. The devulcanization process was carried out at various barrel temperatures and screw speeds (40, 80 and 120 r/min). The lowest sol fraction was obtained for devulcanized waste commercial butyl rubber (D-BR3). According to Horikx theory, devulcanized butyl rubber (D-BR1) presented mainly crosslink breakup while devulcanized bromobutyl rubber (D-BR2) and devulcanized waste commercial butyl rubber (D-BR3) showed a mixture of main chain and crosslink scission. As cure rheographs at 190°C indicated, the addition of devulcanized rubbers to the corresponding virgin ones influenced both scorch and optimal cure times. The tensile properties of devulcanized/virgin rubber blends changed depending on the blend type and virgin rubber. The stress relaxation experiment revealed that the addition of devulcanized rubber to virgin one mostly influenced short relaxation times and also decreased G0. BR1/D-BR3 blends exhibited higher elastic component than BR1/D-BR1 and BR2/D-BR2 samples. The Han plots revealed higher compatibility for BR2/D-BR2 blends.
MarklELacknerM. Devulcanization technologies for recycling of tire-derived rubber: a review. Materials2020; 13: 1246.
2.
AdhikariBDeDMaitiS, et al.Reclamation and recycling of waste rubber. Prog Polym Sci2000; 25: 909–948.
3.
MasseyLK. Permeability properties of plastics and elastomers. 2rd ed.Norwich, NY: Williams Andrew Publishing, 2003. Chaper 77.
4.
TelnovAVZavyalovNVKhokhlovYA, et al.Radiation degradation of spent butyl rubbers. Radiat Phys Chem2002; 63: 245–248.
5.
VisakhPMSabuTArupKC, et al.Advances in elastomers I: blends and interpenetrating networks. Berlin: Springer Science & Business Media, Vol. 11, 2013. DOI: 10.1007/978-3-642-20925-3
6.
AsaroLGrattonMSegharS, et al.Recycling of rubber wastes by devulcanization. Resour Conserv Recycl2018; 133: 250–262.
7.
GhoshJGhoraiSBhuniaS, et al.The role of devulcanizing agent for mechanochemical devulcanization of styrene butadiene rubber vulcanizate. Polym Eng Sci2018; 58: 74–85.
8.
KojimaMTosakaMIkedaY, et al.Devulcanization of carbon black filled natural rubber using supercritical carbon dioxide. J Appl Polym Sci2005; 95: 137–143.
9.
IsayevAIChenJTukachinskyA. Novel ultrasonic technology for devulcanization of waste rubbers. Rubber Chem Technol1995; 68: 267–280.
10.
BockstalLBerchemTSchmetzQ, et al.Devulcanisation and reclaiming of tires and rubber by physical and chemical processes: a review. J Clean Prod2019; 236: 117574.
11.
GarciaPSDe SousaFDBDe LimaJA, et al.Devulcanization of ground tire rubber: physical and chemical changes after different microwave exposure times. Express Polym Lett2015; 9: 1015–1026.
12.
TatangeloVMangiliICaracinoP, et al.Biological devulcanization of ground natural rubber by Gordonia desulfuricans DSM 44462 (T) strain. Appl Microbiol Biotechnol2016; 100: 8931–8942.
13.
FazliARodrigueD. Recycling waste tires into ground tire rubber (GTR)/rubber compounds: a review. J Compos Sci2020; 4: 103.
14.
DiazRColominesGGPeuvrel-DisdierE, et al.Thermo-mechanical recycling of rubber: relationship between material properties and specific mechanical energy. J Mater Process Technol2018; 252: 454–468.
15.
MangiliICollinaEAnzanoM, et al.Characterization and supercritical CO2 devulcanization of cryo-ground tire rubber: influence of devulcanization process on reclaimed material. Polym Degrad Stabil2014; 102: 15–24.
16.
LiuZLiXXuX, et al.Devulcanizaiton of waste tread rubber in supercritical carbon dioxide: operating parameters and product characterization. Polym Degrad Stabil2015; 119: 198–207.
17.
MeysamiMTzoganakisCMutyalaP, et al.Devulcanization of scrap tire rubber with supercritical CO2: a study of the effects of process parameters on the properties of devulcanized rubber. Int Polym Process2017; 32: 183–193.
18.
SegharSAsaroLRolland-MonnetM, et al.Thermo-mechanical devulcanization and recycling of rubber industry waste. Resour Conserv Recycl2019; 144: 180–186.
19.
ZedlerŁKosmelaPOlszewskiA, et al.Recycling of waste rubber by thermo-mechanical treatment in a twin-screw extruder. Proceedings2020; 69: 10. Multidisciplinary Digital Publishing Institute Proceedings, The First International Conference on “Green” Polymer Materials 2020. Basel, Switzerland. Available from: https://www.mdpi.com/2504-3900/69/1/10
20.
van HoekHNoordermeerJHeidemanG, et al.Best practice for de-vulcanization of waste passenger car tire rubber granulate using 2-2 -dibenzamidodiphenyldisulfide as de-vulcanization agent in a twin-screw extruder. Polymers2021; 13: 1139.
21.
SimonDÁBárányT. Effective thermomechanical devulcanization of ground tire rubber with a co-rotating twin-screw extruder. Polym Degrad Stabil2021; 190: 109626.
22.
FengWIsayevAIVon MeerwallE. Molecular mobility in ultrasonically treated butyl gum and devulcanized butyl rubber. Polymer2004; 45: 8459–8467.
LandiniLde AraújoSGLugãoAB, et al.Preliminary analysis to BIIR recovery using the microwave process. Eur Polym J2007; 43: 2725–2731.
25.
KhavarniaMMovahedSO. Butyl rubber reclamation by combined microwave radiation and chemical reagents. J Appl Polym Sci2016; 133: 1.
26.
JiangKShiJGeY, et al.Complete devulcanization of sulfur-cured butyl rubber by using supercritical carbon dioxide. J Appl Polym Sci2013; 127: 2397–2406.
27.
KaraağaçBŞenMDenizV, et al.Recycling of gamma irradiated inner tubes in butyl based rubber compounds. Nucl Instrum Methods Phys Res Sect B Beam Interact Mater Atoms2007; 265: 290–293.
28.
JalilvandARGhasemiIKarrabiM, et al.A study of EPDM devulcanization in a co-rotating twin-screw extruder. Iran Polym J (Engl Ed)2007; 16: 327.
29.
JalilvandAGhasemiIKarrabiM, et al.Using devulcanized EPDM in PP/HDPE/EPDM ternary blend: mechanical properties and morphology. Iran Polym J (Engl Ed)2007; 16: 637.
30.
YazdaniHGhasemiIKarrabiM, et al.Continuous devulcanization of waste tires by using a co-rotating twin screw extruder: effects of screw configuration, temperature profile, and devulcanization agent concentration. J Vinyl Addit Technol2013; 19: 65–72.
31.
YazdaniHKarrabiMGhasmiI, et al.Devulcanization of waste tires using a twin-screw extruder: the effects of processing conditions. J Vinyl Addit Technol2011; 17: 64–69.
32.
BartonAM. Handbook of polymer-liquid interaction parameters and solubility parameters. 1st ed.New York, NY: Routledge, 2018, p. 73.
33.
BaetaDAZatteraJAOliveiraMG, et al.The use of styrene-butadiene rubber waste as a potential filler in nitrile rubber: order of addition and size of waste particles. Braz J Chem Eng2009; 26: 23–31.
34.
HorikxMM. Chain scissions in a polymer network. J Polym Sci1956; 19: 445–454.
35.
VerbruggenMALVan Der DoesLDierkesWK, et al.Experimental validation of the Charlesby and Horikx models applied to de-vulcanization of sulfur and peroxide vulcanizates of NR and EPDM. Rubber Chem Technol2016; 89: 671–688.
36.
SaiwariSDierkesWKNoordermeerJWM. Comparative investigation of the devulcanization parameters of tire rubbers. Rubber Chem Technol2014; 87: 31–42.
37.
SegharSAsaroLAït HocineN. Experimental validation of the Horikx theory to be used in the rubber devulcanization analysis. J Polym Environ2019; 27: 2318–2323.
38.
SabzekarMZohuriGChenarMP, et al.A new approach for reclaiming of waste automotive EPDM rubber using waste oil. Polym Degrad Stabil2016; 129: 56–62.
39.
FormelaKCysewskaMHaponiukJT. Thermomechanical reclaiming of ground tire rubber via extrusion at low temperature: efficiency and limits. J Vinyl Addit Technol2014; 22: 213–221.
40.
IsmailHNordinRNoorAM. Cure characteristics, tensile properties and swelling behaviour of recycled rubber powder-filled natural rubber compounds. Polym Test2002; 21: 565–569.
41.
SreejaTDKuttySKN. Cure characteristics and mechanical properties of natural rubber/reclaimed rubber blends. Polym Plast Technol Eng2000; 39: 501–512.
42.
FazliARodrigueD. Waste rubber recycling: a review on the evolution and properties of thermoplastic elastomers. Materials2020; 13: 782.
KwagHRanaDChoK, et al.Binary blends of metallocene polyethylene with conventional polyolefins: rheological and morphological properties. Polym Eng Sci2000; 40: 1672–1681.
45.
HanCDChuangH. Criteria for rheological compatibility of polymer blends. J Appl Polym Sci1985; 30: 4431–4454.
