Transformation of vulcanized natural rubber into lower molecular weight polymers and their application to grafted copolymer synthesis with some vinyl monomers

Abstract

Graft copolymerization of several vinyl monomers onto polyisoprene was carried out to explore the possibility to recycle waste rubber to useful functional materials. Synthetic polyisoprene, vulcanized natural rubber, and vulcanized natural rubber with carbon black were converted to lower molecular weight polymers at 300°C, under air or nitrogen atmosphere. The obtained low molecular weight natural rubber and polyisoprene were soluble in organic solvents, such as hexane, toluene, tetrahydrofuran (THF), chloroform, and monochlorobenzene. Radical copolymerization of styrene with a thermally fragmented natural rubber was carried out at 80°C in bulk for 2 h in the presence of 2,2Ј-azobis(isobutyronitrile) (AIBN) under air atmosphere to give the corresponding grafted copolymer. The obtained polymer was a beige powdery copolymer at room temperature and consisted of isoprene (38 mol %) and styrene (62 mol %) units, respectively.

Mechanistic Understanding of Polycyclic Aromatic Hydrocarbons (PAHs) from the Thermal Degradation of Tires under Various Oxygen Concentration Atmospheres

“…6 The combustion of these fuels produces nonmethane hydrocarbons (NMHCs). 7 PAHs, a group of ubiquitous organic contaminants are included in the list of NMHCs and are subject of public concern due to their demonstrated carcinogenic and mutagenic potential. Thus, the United States Environmental Protection Agency (USEPA) has listed 14 hazardous air pollutants (HAPs), believed to be present in the aircraft exhaust.…”

“…The primary aviation and internal combustion engine fuels are kerosene-range distillates . The combustion of these fuels produces nonmethane hydrocarbons (NMHCs) . PAHs, a group of ubiquitous organic contaminants are included in the list of NMHCs and are subject of public concern due to their demonstrated carcinogenic and mutagenic potential.…”

“…Tires are composed of a polymer mixture, , which are mainly natural rubber (NR) called as polyisoprene (IR) , and styrene butadiene rubber (SBR) . In addition, black carbon, fiber, extender, and vulcanizing agents are added during the manufacturing, which leads to the complex thermal degradation behavior. ,,,, Considerable work has been achieved to characterize the thermal degradation behavior through the kinetic parameters , using a TGA unit. In addition, air pollution generation through tire combustion has been investigated as an overall process level, − which has led to little information on the pathway of VOC and PAH formation from the tire combustion process. ,,, …”

Separation of core-shell structured carbon black nanoparticles from waste tires by light pyrolysis

“…Low temperature pyrolysis could reduce the energy cost but the properties of the reclaimed CB p were not competitive to those of commercial carbon black [15]. Yamazaki et al [16] converted waste tires to * * Corresponding author.…”

Buckminsterfullerene: A Strong, Covalently Bonded, Reinforcing Filler and Reversible Cross-Linker in the Form of Clusters in a Polymer

“…But most importantly, the reversibility of C 60 –C 60 cross-links is very interesting for improved recycling of composite materials. Recycling of rubber-based composite materials (network polymers) is troublesome because of difficulties to break down the chemically cross-linked microstructure . In a polymer composite which is cross-linked only by dimeric or polymeric C 60 , it would be possible to recycle the polymer matrix as well as a (second) reinforcing system, e.g., one made of carbon fibers, providing both environmental and cost savings.…”