Thermal analysis of the sulfur vulcanization

Sowińska

2019

J Therm Anal Calorim

Different thermal analysis techniques were used to study the effect of fillers and ionic liquids (ILs) on the vulcanization process, thermal and dynamic mechanical properties of acrylonitrile-butadiene elastomer (NBR). The products of the studies were composites of NBR filled with hydrotalcite, nanosized silica or carbon black. ILs such as 1-butyl-1-methylpyrrolidinium (BMpyrrolBF 4), 1-butyl-4-methylpyridinium (BMpyrBF 4) or 1-butyl-1-methylpiperidinium (BMpipBF 4) tetrafluoroborates were applied to improve the dispersion degree of the curatives and filler particles in the elastomer and to increase the efficiency of vulcanization. The differential scanning calorimetry results indicated that ILs reduced the vulcanization temperature of NBR compounds and increased the homogeneity of cross-link distribution in the elastomer network. NBRs filled with carbon black or silica exhibited similar thermal stabilities, whereas hydrotalcite reduced the temperature of thermal decomposition. The lowest mechanical loss factors were determined for vulcanizates filled with nanosized silica.

Section: Temperature and Enthalpy Of Vulcanizationmentioning

confidence: 99%

Thermal characterization of the effect of fillers and ionic liquids on the vulcanization and properties of acrylonitrile–butadiene elastomer

Sowińska

2019

J Therm Anal Calorim

“…The influence of the tested additives on the vulcanization process of CR was also studied using the DSC analysis. This method is commonly used to investigate the curing process of polymers 15,[33][34][35] and allows for the determination of the temperature and the enthalpy of vulcanization. The results are given in Table 5.…”

Section: Thermal Evaluation Of Cr Vulcanization and Thermal Stabilimentioning

confidence: 99%

CR composites with improved processing safety crosslinked via Heck's reaction

Dziemidkiewicz

J of Applied Polymer Sci

2020

The aim of this study was to optimize the composition of the chloroprene rubber (CR) composites crosslinked via the Heck-type reaction to ensure their safe processing at elevated temperature. The developed curing system consisting of iron (III) acetylacetonate (Fe(acac)) and triethanolamine (TEOA) demonstrates high activity and more eco-friendly composition in comparison with metal oxide system, commercially used for CR crosslinking. However, the high activity of Fe(acac)/TEOA system results in a short scorch time, which is the greatest disadvantage regarding the safe processing of CR rubber and thus, must be improved. Therefore, CR compounds with Fe(acac) in the presence of different additives were studied. The longest scorch times (t 02) were observed for rubber compounds with urotropine (U), N-cyclohexyl-2-benzothiazole sulfenamide (CBS) or salicylic acid. Moreover, vulcanizates containing these additives exhibited higher tensile strengths and elongation at breaks compared to CR crosslinked with Fe(acac)/TEOA system.

“…The influence of the proposed new curing system on the vulcanization process of BIIR was also studied using the DSC analysis, which allowed for the determination of the temperature and the enthalpy of vulcanization. This method is commonly used to investigate the curing process of polymers [21][22][23][24]. The results are given in Table 3.…”

Section: Thermal Evaluation Of Biir Vulcanization Process and Thermalmentioning

confidence: 99%

Thermal analysis of halogenated rubber cured with a new cross-linking system

Dziemidkiewicz

Pingot

2019

J Therm Anal Calorim

The aim of this work was to examine the influence of new curing agents proposed for brominated butyl rubber (BIIR) on the cross-linking process of rubber compounds and the thermal behavior of the vulcanizates. Rubber blends that were filled with carbon black and contained acetylacetonates of different transition metals in the presence of triethanolamine (TEOA) as new cross-linking agents were prepared. The performed studies showed that metal acetylacetonates (Me(acac)) are effective cross-linking agents for BIIR, which was confirmed by high values of the torque increment (∆M) and significant cross-linking degree of the vulcanizates (α (T)). The most active curing agent seems to be iron acetylacetonate (Fe(acac)). Its application results in a shorter optimal vulcanization time, lower onset vulcanization temperature and similar vulcanization enthalpy compared to the BIIR cured with a sulfur curing system. The BIIR vulcanizates cured with Me(acac) reveal good mechanical properties with tensile strengths in the range of 9-14 MPa and better damping properties comparing to the sulfur-cured rubber. The proposed curing agents do not significantly affect the thermal stability of the BIIR vulcanizates.