Polyaniline as an antioxidant and antirad in SBR vulcanizates

Some novel polyamines as antioxidants for SBR vulcanizates

Seven organo-phosphorus compounds were synthesized and incorporated in natural rubber (NR) and styrene-butadiene rubber (SBR) mixes The rheometric characteristics of the green rubber mixes were determined using the oscillating disc rheometer The prepared compounds were evaluated as thermal stabilizers and antifatigue agents in NR and SBR vulcanizates The results revealed that the prepared compounds were good antioxidants and antifatigue agents for rubber vulcanizates exceeding the commercial antioxidant 4-methyl-2,6-di-tert-butyl phenol, which is used in the rubber industry In addition, the efficiency of such compounds depends on their chemical structure

Evaluation of New Thermal Stabilizers and Antifatigue Agents for Rubber Vulcanizates

The infrared and Raman spectra of 3,6-dichloropyridazine and 3,4,5-trichloropyridazine were recorded. These spectra were taken in the solid phase and with various solvents (HCCl3, CS2, CCl4), giving wavenumbers and relative intensities of the bands and the qualitative Raman depolarization ratios. Conventional ab initio methods at the Hartree−Fock and MP2 levels using the 3-21G*, 6-31G*, 6-31G**, and 6-311G** basis sets, as well as density functional theory (DFT) using the 6-31G* basis functions and the BLYP and B3LYP functionals, were used to predict the geometries and to calculate the harmonic frequencies and force fields of these molecules. In addition, coupled cluster calculations, i.e., CCSD and CCSD(T), using the 6-311G** basis set were included to evaluate the geometries of pyridazine and 3,6-dichloropyridazine, analyzing in detail the structure of these systems. To fit the calculated wavenumbers to the experimental ones, the B3LYP/6-31G* force field was selected to be scaled. The following two sets...

Experimental and Theoretical Analysis of the Vibrational Spectra and Theoretical Study of the Structures of 3,6-Dichloropyridazine and 3,4,5-Trichloropyridazine

Itaconic acid was reacted with phenylene diamine (ortho, meta and para) and o‐tolidine in boiling dekalin, using Dean and Stark apparatus. The polymers prepared were evaluated for their suitability as antioxidants for natural rubber vulcanizates. The amide polymers prepared showed high efficiency as antioxidants for rubber vulcanizates, exceeding the performance of commercial antioxidants. In addition, the results obtained are encouraging and support the use of these polymers from both the environmental and economical points of view.

Evaluation of itaconic acid/aromatic diamine adducts as novel antioxidants polymers. Part 1: Evaluation as antioxidants for natural rubber vulcanizates

Four pyridazine derivatives were synthesized and evaluated as accelerators in natural rubber (NR) mixes. The rheological characteristics were determined by a Monsanto Rheometer 100. The kinetic constants for the vulcanization reaction in the presence of the synthetic compounds were calculated using the rheometric data. The compounds showed a good accelerating efficiency compared with mercaptobenzothiazole (MBT), which is widely used in rubber industry.



Vier Pyridazinderivate wurden synthetisiert und als Beschleuniger fur Naturkautschukmischungen entwickelt. Die rheologischen Eigenschaften wurden mit Hilfe eines Monsanto Rheometers 100 bestimmt. Die rheometrischen Daten wurden fur die Berechnung der kinetischen Konstanten der Vulkanisationsreaktion in Anwesenheit der synthetisierten Verbindungen benutzt. Verglichen mit Mercaptobenzthiazol (MBT), einem Beschleuniger der haufig in der Kautschukindustrie eingesetzt wird, zeigten diese Verbindungen eine gute Beschleunigerwirksamkeit.

M. N. Ismail

Papers

Synthesis and evaluation of pyridazines in natural rubber