Stabilisation of metallocene ethylene-1-octene copolymers during multiple extrusions

Research output: Contribution to journalSpecial issue

Abstract

The melt stabilising efficiency of antioxidants with different structures based on hindered phenols, phosphite esters, phosphonite and a lactone was examined during multi-pass extrusions at 265 °C in three metallocene ethylene-1-octene copolymers (m-LLDPE) having different extent of short chain branching (SCB) and one Zeigler copolymer (z-LLDPE) containing the same level of SCB corresponding to one of the m-LLDPE polymers. The effect of the different antioxidants, when used separately and in combination, was investigated by characterising the changes in the polymer's rheological behaviour, colour formation and structural changes based on unsaturated groups and carbonyl content during five multi-pass extrusions. The results showed that all stabilisation systems examined offered higher efficiency in the metallocene polymers compared to the Zeigler. The effect of the extent of SCB in the metallocene polymers on the stabilising efficacy of the antioxidant systems was also examined, and it was shown that it had a significant effect, with both single and combinations of antioxidants giving higher efficiency in the m-LLDPE polymer containing higher extent of SCB. The presence of the lactone HP136 in mixtures containing hindered phenol–phosphite antioxidant systems gave a higher melt stabilisation efficiency than in its absence and this has been attributed to a co-operative antioxidant reaction steps that take place between the antioxidants resulting in the possible regeneration of the lactone antioxidant through a redox reaction. In all the metallocene PE polymers examined, the biologically hindered phenol, Irganox E, was shown to be more effective than the conventionally hindered phenol Irganox 1076, when examined alone or in combination with phosphite esters.
Original languageEnglish
Pages (from-to)1619-1631
Number of pages13
JournalPolymer Degradation and Stability
Volume93
Issue number9
DOIs
Publication statusPublished - Sep 2008

Fingerprint

antioxidants
Antioxidants
Extrusion
copolymers
Ethylene
ethylene
Copolymers
Stabilization
stabilization
Polymers
Linear low density polyethylenes
Lactones
phenols
Phosphites
Phenols
polymers
Phenol
esters
Esters
high polymers

Bibliographical note

27th Polymer Degradation Discussion Conference, held at Aston University, Birmingham, UK, September 2008, in honour of Professor Norman Billingham for Lifelong Career in Polymer Science

Keywords

  • stabilisation
  • m-LLDPE
  • melt extrusion
  • antioxidants

Cite this

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title = "Stabilisation of metallocene ethylene-1-octene copolymers during multiple extrusions",
abstract = "The melt stabilising efficiency of antioxidants with different structures based on hindered phenols, phosphite esters, phosphonite and a lactone was examined during multi-pass extrusions at 265 °C in three metallocene ethylene-1-octene copolymers (m-LLDPE) having different extent of short chain branching (SCB) and one Zeigler copolymer (z-LLDPE) containing the same level of SCB corresponding to one of the m-LLDPE polymers. The effect of the different antioxidants, when used separately and in combination, was investigated by characterising the changes in the polymer's rheological behaviour, colour formation and structural changes based on unsaturated groups and carbonyl content during five multi-pass extrusions. The results showed that all stabilisation systems examined offered higher efficiency in the metallocene polymers compared to the Zeigler. The effect of the extent of SCB in the metallocene polymers on the stabilising efficacy of the antioxidant systems was also examined, and it was shown that it had a significant effect, with both single and combinations of antioxidants giving higher efficiency in the m-LLDPE polymer containing higher extent of SCB. The presence of the lactone HP136 in mixtures containing hindered phenol–phosphite antioxidant systems gave a higher melt stabilisation efficiency than in its absence and this has been attributed to a co-operative antioxidant reaction steps that take place between the antioxidants resulting in the possible regeneration of the lactone antioxidant through a redox reaction. In all the metallocene PE polymers examined, the biologically hindered phenol, Irganox E, was shown to be more effective than the conventionally hindered phenol Irganox 1076, when examined alone or in combination with phosphite esters.",
keywords = "stabilisation, m-LLDPE, melt extrusion, antioxidants",
author = "Sahar Al-Malaika and X. Peng",
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volume = "93",
pages = "1619--1631",
journal = "Polymer Degradation and Stability",
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}

Stabilisation of metallocene ethylene-1-octene copolymers during multiple extrusions. / Al-Malaika, Sahar; Peng, X.

In: Polymer Degradation and Stability, Vol. 93, No. 9, 09.2008, p. 1619-1631.

Research output: Contribution to journalSpecial issue

TY - JOUR

T1 - Stabilisation of metallocene ethylene-1-octene copolymers during multiple extrusions

AU - Al-Malaika, Sahar

AU - Peng, X.

N1 - 27th Polymer Degradation Discussion Conference, held at Aston University, Birmingham, UK, September 2008, in honour of Professor Norman Billingham for Lifelong Career in Polymer Science

PY - 2008/9

Y1 - 2008/9

N2 - The melt stabilising efficiency of antioxidants with different structures based on hindered phenols, phosphite esters, phosphonite and a lactone was examined during multi-pass extrusions at 265 °C in three metallocene ethylene-1-octene copolymers (m-LLDPE) having different extent of short chain branching (SCB) and one Zeigler copolymer (z-LLDPE) containing the same level of SCB corresponding to one of the m-LLDPE polymers. The effect of the different antioxidants, when used separately and in combination, was investigated by characterising the changes in the polymer's rheological behaviour, colour formation and structural changes based on unsaturated groups and carbonyl content during five multi-pass extrusions. The results showed that all stabilisation systems examined offered higher efficiency in the metallocene polymers compared to the Zeigler. The effect of the extent of SCB in the metallocene polymers on the stabilising efficacy of the antioxidant systems was also examined, and it was shown that it had a significant effect, with both single and combinations of antioxidants giving higher efficiency in the m-LLDPE polymer containing higher extent of SCB. The presence of the lactone HP136 in mixtures containing hindered phenol–phosphite antioxidant systems gave a higher melt stabilisation efficiency than in its absence and this has been attributed to a co-operative antioxidant reaction steps that take place between the antioxidants resulting in the possible regeneration of the lactone antioxidant through a redox reaction. In all the metallocene PE polymers examined, the biologically hindered phenol, Irganox E, was shown to be more effective than the conventionally hindered phenol Irganox 1076, when examined alone or in combination with phosphite esters.

AB - The melt stabilising efficiency of antioxidants with different structures based on hindered phenols, phosphite esters, phosphonite and a lactone was examined during multi-pass extrusions at 265 °C in three metallocene ethylene-1-octene copolymers (m-LLDPE) having different extent of short chain branching (SCB) and one Zeigler copolymer (z-LLDPE) containing the same level of SCB corresponding to one of the m-LLDPE polymers. The effect of the different antioxidants, when used separately and in combination, was investigated by characterising the changes in the polymer's rheological behaviour, colour formation and structural changes based on unsaturated groups and carbonyl content during five multi-pass extrusions. The results showed that all stabilisation systems examined offered higher efficiency in the metallocene polymers compared to the Zeigler. The effect of the extent of SCB in the metallocene polymers on the stabilising efficacy of the antioxidant systems was also examined, and it was shown that it had a significant effect, with both single and combinations of antioxidants giving higher efficiency in the m-LLDPE polymer containing higher extent of SCB. The presence of the lactone HP136 in mixtures containing hindered phenol–phosphite antioxidant systems gave a higher melt stabilisation efficiency than in its absence and this has been attributed to a co-operative antioxidant reaction steps that take place between the antioxidants resulting in the possible regeneration of the lactone antioxidant through a redox reaction. In all the metallocene PE polymers examined, the biologically hindered phenol, Irganox E, was shown to be more effective than the conventionally hindered phenol Irganox 1076, when examined alone or in combination with phosphite esters.

KW - stabilisation

KW - m-LLDPE

KW - melt extrusion

KW - antioxidants

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U2 - 10.1016/j.polymdegradstab.2008.06.005

DO - 10.1016/j.polymdegradstab.2008.06.005

M3 - Special issue

VL - 93

SP - 1619

EP - 1631

JO - Polymer Degradation and Stability

JF - Polymer Degradation and Stability

SN - 0141-3910

IS - 9

ER -