Search results for "Organic peroxide"
showing 6 items of 6 documents
Stabilisation of LDPE cross-linked in the presence of peroxides III. Mass spectrometric study of chemical changes taking place in the n-octadecane–di…
2000
Abstract An attempt was made to identify the products of the reaction between dicumyl peroxide and Irganox 1081, carried out in n -octadecane (saturated hydrocarbon), in conditions of fast decomposition of the peroxide (180°C, 5 min). Mass spectrometry (MS) was employed to find m/z values of molecular and fragment ions in analyses of the components ( n -octadecane, dicumyl peroxide, Irganox 1081) and of the following systems: n -octadecane–dicumyl peroxide, n -octadecane–Irganox 1081 and n -octadecane–dicumyl peroxide–Irganox 1081, after holding them at a temperature of 180°C for 5 min. The tendency of sulphur in Irganox 1081 to oxidise, specifically in the presence of dicumyl peroxide, was…
Stabilisation of LDPE cross-linked in the presence of peroxidesII. FTIR study of chemical changes taking place in the LDPE–dicumyl peroxide–Irganox 1…
2000
Abstract The chemical changes taking place in the systems: LDPE–Irganox 1081, LDPE–dicumyl peroxide and LDPE–Irganox 1081–dicumyl peroxide, after homogenisation (in a rolling mill at 130°C) and after homogenisation and cross-linking (at 180°C and 5.0 MPa for 20 min) were investigated by FTIR. It was found that the OH groups in Irganox 1081 were in a bound form, and were most probably linked to the sulphur co-ordination centre. Further, the presence of dicumyl peroxide without Irganox 1081 in LDPE resulted in the formation of hydroperoxide groups at a temperature of 130°C, which were replaced by free hydroxy and carbonyl groups of a ketonic type after cross-linking. Simultaneous addition of …
Effects of functionalized carbon nanotubes in peroxide crosslinking of diene elastomers
2009
Abstract The crosslinking reaction of ethylene–propylene–diene terpolymer (EPDM) peroxide vulcanization filled with pristine and functionalized carbon nanotubes (CNTs and S/CNTs) was evaluated by rheometric tests. The functionalization of CNTs was carried out by diazonium salt methodology in acid medium. S/CNTs were characterised by means of TGA, EDX, Raman and elemental analysis. Pristine CNTs were found to gradually increase the delta torque as a function of loading fraction. Nevertheless, the vulcanization time, scorch and optimum cure time hardly varied on addition of CNTs. However, S/CNTs noticeably affected the cure process, reducing the vulcanization time and delta torque. This effec…
Structural, mechanical and thermal behavior assessments of PCL/PHB blends reactively compatibilized with organic peroxides
2018
Abstract The efficiency of two commercially available organic peroxides, dicumyl peroxide (DCP) and di-(2-tert-butyl-peroxyisopropyl)-benzene (BIB), during reactive processing of poly(e-caprolactone)/poly(3-hydroxybutyrate) (PCL/PHB) blends was investigated. The changes in chemical structure of PCL/PHB blends, as a function of organic peroxide type (DCP/BIB) and content (in range: 0–1.0 parts by weight - pbw), were characterized by Fourier transform infrared spectroscopy, thermogravimetric analysis combined with infrared spectroscopy, and headspace analysis combined with gas chromatography with flame ionization detector. Performance properties of PCL/PHB blends were evaluated based on diffe…
Identification of organic hydroperoxides and hydroperoxy acids in secondary organic aerosol formed during the ozonolysis of different monoterpenes an…
2009
On-line ion trap mass spectrometry (ITMS) enables the real-time characterization of reaction products of secondary organic aerosol (SOA). The analysis was conducted by directly introducing the aerosol particles into the ion source. Positive-ion chemical ionization at atmospheric pressure (APCI(+)) ITMS was used for the characterization of constituents of biogenic SOA produced in reaction-chamber experiments. APCI in the positive-ion mode usually enables the detection of [M+H](+) ions of the individual SOA components. In this paper the identification of organic peroxides from biogenic volatile organic compounds (VOCs) by on-line APCI-ITMS is presented. Organic peroxides containing a hydroper…
One electron transfer chain decomposition of trifluoroacetone diperoxide: The first 1,2,4,5-tetroxane with O-transfer capability
1992
Abstract Reaction of 1,1,1-trifluoropropanone (trifluoroacetone) ( 1a ) with 30% hydrogen peroxide in the presence of conc. sulfuric acid afforded in good yield 3,6-bis(trifluoromethyl)-3,6-dimethyl-1,2,4,5-tetroxane or trifluoroacetone diperoxide ( 2a ). Peroxide 2a is quantitatively converted into trifluoroacetone ( 1a ) and dioxygen by a catalytic amount of tetrabutylammonium iodide through a reductive electron transfer chain reaction carried out by the superoxide ion. Trifluoroacetone diperoxide ( 2a ) is capable of O-atom transfer to alkenes and sulfides.