Calculation and Analysis of the Molecular Weight Characteristics of the Polymer in the Synthesis of Butyl Rubber

The article compiled a mathematical model of the cationic copolymerization of isobutylene and isoprene using a catalyst AlCl3 in a CH3Cl solution, including the reactions of initiation, chain growth, chain transfer to the monomer, and chain termination. The molecular weight characteristics of butyl rubber synthesized in methyl chloride using a catalytic system based on aluminum trichloride have been investigated. Relationships are obtained for calculating the moments of the molecular weight characteristics of butyl rubber. The effect of the concentration of the initiator on the conversion versus time was investigated.

Field Study for PAH Absorption Performances of Butyl Rubber, PDMS, and SPMD Passive Samplers

Polycyclic aromatic hydrocarbons (PAHs) are organic pollutants having various adverse effects on the marine ecosystem. Because of their low solubility in the marine environment, their detection and monitoring in the water column are challenging tasks. Passive samplers are used to detect PAHs in aquatic environments as complementary tools to conventional water sampling. In the present study, PAH absorbance performances of four butyl rubber-based (BR) passive samplers with different structures (SN5, SN10, DN, and TN) and commercialized passive samplers (SPMD and PDMS) were determined. Stainless steel cages containing passive samplers were deployed in the water column in Istinye Bay, Istanbul, and retrieved after 7 and 28 days. Collected samplers were analyzed in the laboratory to determine their PAH contents. Results showed that, even though the SPMD samplers had the highest total PAH content, they were not able to collect PAHs with log Kow value of above 6.0. Similarly, PAHs with log Kow values higher than 5.5 could have not been collected by PDMS samplers. In contrast, BR-based passive samplers have sampled also high molecular weight PAHs in the water column, and SN10 sampler showed the highest performance in terms of the collected PAHs. Results highlighted that SN10 sampler has a wide absorption range when it is compared with the commercialized samplers, and it has also advanced absorption performance relative to the other BR samplers.

Enhancement of thermoelectric and mechanical properties of thermoplastic vulcanizates (TPVs) with hydroxylated graphene by dynamic vulcanization

In order to obtain higher thermoelectric and mechanical properties in nonpolar thermoplastic vulcanizates (TPVs), the butyl rubber/polypropylene (TPVs)/hydroxylated graphene (HGE) composites with nanosheet network were prepared through masterbatch technique and based on thermodynamic calculations, using polypropylene-graft-maleic anhydride (PP-MA) as a compatibilizer. The Fourier transform infrared (FTIR) and Raman spectra revealed the introduced maleic anhydride group on PP-MA can form strong interfacial interaction with hydroxyl-containing functional groups on HGE. Morphology study indicated the rubber particles in the composites occupied the most volume of the PP phase, as expected to hinder the aggregation of HGE and form the effective nanosheet network. The nanosheet network can be combined with the butyl rubber (IIR) cross-linked particles during the dynamic vulcanization process to improve the interface bonding between PP and IIR, thus increasing the tensile strength of TPVs. The prepared TPVs/HGE composites have significantly improved in mechanical properties, thermal properties and dielectric properties, which provides a guarantee for their potential application as multifunctional TPVs polymers.

Thermal Decomposition of Brominated Butyl Rubber

The thermal decomposition of brominated butyl rubber under air atmosphere was investigated by thermogravimetry (TG) and derivative thermogravimetry (DTG) at various heating rates. The kinetic parameters were evaluated by TG and the isoconversional method developed by Ozawa. One prominent decomposition stage was observed in the DTG curves at high heating rates, while an additional small peak was observed at low heating rates. The apparent activation energy determined using the TG method ranged from 219.31 to 228.13 kJ·mol−1 at various heating rates. The non-isothermal degradation was found to be a first-order reaction, and the activation energy, as determined by the isoconversional method, increased with an increase in mass loss. The kinetic data suggest that brominated butyl rubber has excellent thermal stability. This study can indirectly aid in improving rubber pyrolysis methods and in enhancing the heat resistance of materials.

Thermal Decomposition of Brominated Butyl Rubber

The thermal decomposition of brominated butyl rubber under air atmosphere was investigated by thermogravimetry (TG) and derivative thermogravimetry (DTG) at various heating rates. The kinetic parameters were evaluated by TG and the isoconversional method developed by Ozawa. One prominent decomposition stage was observed in the DTG curves at high heating rates while an additional small peak was observed at low heating rates. The apparent activation energy determined using the TG method ranged from 219.31–228.13 kJ·mol-1 at various heating rates. The non-isothermal degradation was found to be a first order reaction, and the activation energy, as determined by the isoconversional method, increased with an increase in mass loss. The kinetic data suggested that brominated butyl rubber had excellent thermal stability. This study will indirectly aid in improving rubber pyrolysis methods and in enhancing the heat resistance of materials.