Composição de borracha vulcanizada com compostos de enxofre e processo de vulcanização de borracha

Em 04/04/2017: Anuidade de pedido de patente de invenção no prazo ordinário.DepositadaÉ descrita uma composição de borracha vulcanizada com compostos de enxofre que compreende 100 phr de uma borracha selecionada dentre o grupo que consiste de borracha natural ou uma borracha derivada de dienos, e misturas das mesmas; entre 1,5 e 4 phr de ácido esteárico; entre 2,0 e 4,0 phr de óxido de zinco; entre 1,0 e 3,0 phr de antioxidante; entre 0 e 50 phr de negro de fumo; entre 0,5 e 2 phr em relação à borracha, de um complexo metálico de ditiocarbimato ou de trítiocarbimato, e entre 0,5 e 6 phr de enxofre, um doador de enxofre ou misturas dos mesmos. É igualmente descrito o processo de vulcanização da dita composição. Por aquecimento da composição não há liberação de nitrosaminas nocivas ao meio ambiente

Rheological Behavior of Renewable Polyethylene (HDPE) Composites and Sponge Gourd ( Luffa cylindrica

The present study reports the results of rheological behavior of renewable composites, based on a matrix of high density polyethylene (HDPE), made from ethanol distilled from sugarcane, and lignocellulose filler from waste generated in the processing of sponge gourds for bathing use. The composites were prepared with 10, 20, 30, and 40%wt of filler in a twin-screw extruder. The materials were analyzed in a parallel plate rheometer and a melt-flow indexer. The composite morphology was determined by scanning electron microscopy. The composite viscosity increased with filler content, suggesting possible formation of filler agglomerates. This result was confirmed by Cole-Cole diagrams

Tannin Treated Water for use in the Emulsion Polymerization of SBR

Abstract: The toxicity of residues formed during water treatment is mainly a function of the chemicals used. The inorganic flocculants, when used, give rise to compounds harmful to humans and to the environment. An alternative solution is the use of tannins. However, despite the environmental benefits, when using tannin-based products in the treatment of industrial water, modifications may be imparted to the final product. In this work, tannin was evaluated as flocculating agent to treat the water used in the emulsion polymerization to produce SBR. The results show that good stability of the latex and acceptable color in the rubber can be achieved

Syntheses, crystal structure and spectroscopic characterization of bis(dithiocarbimato)zinc(II) complexes: A new class of vulcanization accelerators

The compounds (Ph4P)2[Zn(RSO2N = CS2)2] [Ph4P+ = tetraphenylphosphanium cation; R = CH3 (1b), CH3CH2 (2b), CH3(CH2)3 (3b) and CH3(CH2)7 (4b)] were synthesized by the reaction of RSO2N = CS2K2·2H2O (1a–4a) with Zn(CH3COO)2·2H2O and Ph4PCl. The IR data were consistent with the formation of bis(dithiocarbimato)zinc(II) complexes. The NMR spectra showed the expected signals for the cation and the dithiocarbimate anionic complex in a 2:1 proportion. The compound 3b was also characterized by X-ray diffraction in the triclinic P1¯ space group, with the Zn atom in a general crystallographic position, being coordinated by four sulfur atoms in a distorted tetrahedral coordination environment. The activity of compounds 1b–4b in the vulcanization of the natural rubber was evaluated and compared to the commercial accelerators CBS, MBTS and TMTD. These studies confirm that the bis(dithiocarbimato)zinc(II) complexes are new vulcanization accelerators, showing a similar degree of cure as MBTS, and scorch time values compatible with good processing safety for industrial applications

Syntheses, structural and spectroscopic characterization of novel zinc(II)-bis(trithiocarbimato) complexes and bis(N-methylsulfonyldithiocarbimate)-sulfide.

Four zinc(II)-bis(trithiocarbimato) complexes with the general formula A2[Zn(RSO2N@CS3)2] [A= Ph4P+: R = CH3 (1), 4-CH3C6H4 (2); A = Bu4N+: R = CH3 (3), 4-CH3C6H4 (4)] were obtained by the reaction of sulfur with the correspondent zinc(II)-bis(dithiocarbimato) complexes. Additionally, the compound (Ph4P)2[(CH3SO2N@CS2)2S)] (5) was prepared from the potassium methylsulfonildithiocarbimate by oxidation with iodine. The compounds were characterized by elemental analyses and IR, 1H NMR and 13C NMR spectroscopies. The compounds 4 and 5 were also characterized by X-ray diffraction techniques. The compound 4 crystallizes in the centrosymmetric space group C2/c of the monoclinic system. The Zn(II) is in a distorted tetrahedral environment (ZnS4) in compound 4, and differ from the coordination mode observed in compound 1, which involves one sulfur and one nitrogen atom of each trithiocarbimate ligand. Compound 5 is the first example of a compound containing a bis(N-alkylsulfonyldithiocarbimate)-sulfide dianion and crystallises in the non-centrosymmetric space group P41212 of the tetragonal system