Stabilisation of LDPE cross-linked in the presence of peroxides III. Mass spectrometric study of chemical changes taking place in the n-octadecane–dicumyl peroxide–Irganox 1081 system

Uhniat, Maria; Kudła, S.; Dziwiński, E.; Sudoł, M.

doi:10.1016/s0141-3910(00)00156-7

Cited by 6 publications

(5 citation statements)

References 9 publications

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“…According to UV data, this species would be more conjugated than "dimer" and "trimer" ones. Such species were previously found by Uhniat et al [22] which proposed a triphenolic structure (Scheme 2).…”

Section: Resultssupporting

confidence: 60%

Reactions of antioxidants with molecular oxygen. Part III: Influence of phenolic stabiliser structures on their oxidation in an inert matrix

Navarro

Audouin

Verdú

2011

Polymer Degradation and Stability

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The oxidation of five different phenolic antioxidants in inert substrates has been investigated varying the temperature and oxygen pressure conditions. The stabiliser consumption in this reaction has been quantified by steric exclusion chromatography. The tendency of the variation of the residual antioxidant concentration with exposure time in the presence of oxygen shows a simple apparent first order process in all cases. The kinetic parameters were determined applying this simple kinetic model. The influence of structural characteristics of stabilisers under study on kinetic parameters of the direct reaction with the oxygen has been analysed. On the other hand, the information obtained about reaction products generated for each antioxidant helped us to explain the results obtained.

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Section: Resultssupporting

confidence: 60%

Reactions of antioxidants with molecular oxygen. Part III: Influence of phenolic stabiliser structures on their oxidation in an inert matrix

Navarro

Audouin

Verdú

2011

Polymer Degradation and Stability

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“…This result may attribute to the critical concentration of antioxidants 38. Antioxidants are consumed during process, and the decomposed antioxidants still remain some resistance to oxidation 22. A part of initial antioxidants remained could capture radicals more efficiently than the decomposed antioxidants so that the critical concentration appears.…”

Section: Resultsmentioning

confidence: 99%

“…At high temperatures, antioxidants act effectively to retard the destructive mechanism, slow the rate of chain scission and prevent chain decomposition 10, 16. On the other hand, DCP consumes a lot of antioxidants during crosslinking reaction, leading to a great reduction in oxidation induction time 21–23. A rather high dosage of antioxidants should be used in crosslinkable systems to guarantee the stabilization in material processing and in service life.…”

Section: Introductionmentioning

confidence: 99%

Assessment of hindered phenol antioxidants on processing stability of peroxide‐cure LDPE by rheology and DSC analysis

Zhang

Yang

Song

et al. 2012

J of Applied Polymer Sci

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Influence of commercial phenol antioxidants Irganox 300, 1010, 1035, and 1076 on peroxide-cure reaction of low-density polyethylene (LDPE) was evaluated through isothermal dynamic rheological and nonisothermal differential scanning calorimetry (DSC) testing. The results indicated that phenol antioxidants could reduce storage modulus of LDPE completely crosslinked at 175 C while they have a neglectable effect on gel fracture and activity energy of crosslinking reaction. On the other hand, time sweep dynamic rheological test revealed the antioxidants 1035 and 1076 with low molecular weight and low melting point could significantly depress scorch of crosslinkable LDPE at 135 C. The isothermal time sweep dynamic rheology test method was more sensitive than nonisothermal DSC test for characterizing the influence of phenol antioxidants on crosslinking kinetics of peroxide-cure reaction of LDPE. V C 2012 Wiley Periodicals, Inc. J Appl Polym Sci 126: 939-946, 2012

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“…Primary radicals derived from DCP decomposition deprive hydrogen atoms from polyethylene chains to form macromolecular radicals, which undergo a coupling reaction, which leads to network formation 5–9. Antioxidants are designed to scavenge radicals to prohibit scorching during processing and to prevent cables from oxidation during long‐term service 10–13. Primary and secondary antioxidants are used in combination to obtain the greatest effectiveness and synergism effects.…”

Section: Introductionmentioning

confidence: 99%

“…Negative synergistic effects between crosslinking agents and antioxidants in polyolefins have been investigated extensively 6–12, 14–17. Electron spin resonance (ESR) studies have shown that phenol radicals reach a maximum concentration before alkyl radicals when antioxidants are added to peroxide curing systems 6–9.…”

Section: Introductionmentioning

confidence: 99%

Influence of binary combined systems of antioxidants on the stabilization of peroxide‐cured low‐density polyethylene

Zhang

Yang

Song

et al. 2012

J of Applied Polymer Sci

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The secondary antioxidants Irganox 168 and 242 and dilaurylthiodipropionate (didodecyl-3,3 0 -thiodipropionate) (DLTP) were chosen to be combined with the primary phenol antioxidants Irganox 300, 1010, 1035, and 1076, and the effects of the binary combined systems of antioxidants on the peroxide curing reaction and the long-term stability of crosslinked low-density polyethylene (XLPE) were studied through isothermal dynamic rheological and mechanical testing. The results show that the primary phenol antioxidants with lower melting points had better resistance to scorching and exhibited good synergistic effects with the secondary antioxidants. Irganox 168 had little resistance to scorching, whereas Irganox DLTP had moderate resistance, and Irganox 242 had the greatest resistance. Irganox 168 and DLTP guaranteed the mechanical properties well, whereas Irganox 242 reduced the tensile strength obviously. Irganox 300 and 1035 combined with secondary antioxidants performed poorly in longterm thermal aging test, whereas Irganox 1076 in combination with secondary antioxidants displayed a moderate effect of aging resistance, and Irganox 1010 showed the best effect.

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Stabilisation of LDPE cross-linked in the presence of peroxides III. Mass spectrometric study of chemical changes taking place in the n-octadecane–dicumyl peroxide–Irganox 1081 system

Cited by 6 publications

References 9 publications

Reactions of antioxidants with molecular oxygen. Part III: Influence of phenolic stabiliser structures on their oxidation in an inert matrix

Reactions of antioxidants with molecular oxygen. Part III: Influence of phenolic stabiliser structures on their oxidation in an inert matrix

Assessment of hindered phenol antioxidants on processing stability of peroxide‐cure LDPE by rheology and DSC analysis

Influence of binary combined systems of antioxidants on the stabilization of peroxide‐cured low‐density polyethylene

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