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Preparation and long-term performance of poly(ethylene-co-butyl acrylate) nanocomposites and polyethylene
KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Polymeric Materials. (Professor Ulf Gedde's group)
2012 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

The current study discusses the preparation and long-term performance of polymer composites used for various purposes under different ageing conditions.

The first part deals with the preparation and characterization of polymer nanocomposites based on poly(ethylene-co-butyl acrylate) (EBA–13 and EBA–28 with 13 and 28 wt % butyl acrylate, respectively) and 2–12 wt % (0.5–3 vol %) of aluminum oxide nanoparticles (two types with different specific surface areas and different hydroxyl-group concentrations; uncoated and coated with, respectively, octyltriethoxysilane and aminopropyltriethoxysilane). The nanocomposite with EBA–13 showed better overall nanoparticle dispersion while EBA–28 resulted in poor dispersion, probably due to insufficiently high shear forces acting during extrusion mixing which were unable to break down nanoparticle agglomerates.

The activity of hindered phenolic antioxidant (0.2 wt%) in all EBA nanocomposites was assessed by determining the oxidation induction time using DSC. The composites containing uncoated aluminium oxide nanoparticles showed a much shorter initial OIT than the pristine polymer with the same initial concentration of antioxidant, indicating adsorption of antioxidant onto the nanoparticle surfaces. Composites containing coated nanoparticles showed a significantly smaller decrease in the initial OIT, suggesting the replacement of hydroxyl groups with organic silane tails, decreasing the concentration of available adsorption sites on the nanoparticle surfaces. The decrease in OIT with increasing ageing time in dry air at 90 °C of the nanocomposites was slower than

that of the unfilled pristine polymer, suggesting a slow release of antioxidant from adsorption sites.

The EBA nanocomposites exposed to liquid water at 90°C showed faster decrease of OIT than samples exposed to dry or humid air. The migration rate of antioxidant was controlled by the boundary conditions in the case of ageing in humid air and liquid water. The antioxidant diffusivity was lower for the composites containing uncoated ND than for the composites containing ND coated with octyltriethoxysilane or aminopropyltriethoxysilane.

The migration and chemical consumption of deltamethrin DM, (synthetic pyrethroid) and synergist piperonyl butoxide from molded polyethylene sheets was also studied. Deltamethrin and piperonyl butoxide are often used for food  storage and insect control purposes. DM showed no signs of crystallization and remained in a liquid state after being cooled to room temperature. Exposure of polyethylene compound sheets to liquid water (at 80 & 95 °C), caused degradation and hydrolysis of the ester bond in the DM, present in the prepared material, and generated species containing hydroxyl groups. Liquid chromatography and infrared spectroscopy showed a significant migration of the active species in liquid water, whereas in air at 80 °C (60 and 80 %RH) the loss of DM and PBO was negligible over 30 days.

The long-term performance of medium-density polyethylene stabilized with six different phenolic antioxidants (0.1 wt%) in aqueous chlorinated media at 70 °C was studied. The results were compared with data for previously studied solutions of antioxidants in squalane (a liquid, low molar mass analogue of polyethylene). A linear relationship was established between the time to reach antioxidant depletion in polyethylene tape samples and the time in squalane samples. Infrared spectroscopy and scanning electron microscopy of drawn samples revealed the onset of surface oxidation and surface embrittlement in tape samples exposed beyond the time for antioxidant depletion.

Place, publisher, year, edition, pages
Stockholm: KTH Royal Institute of Technology, 2012. , 57 p.
Series
Trita-CHE-Report, ISSN 1654-1081 ; 2012:44
Keyword [en]
Polymer nanocomposite, nanoparticles, aluminium oxide, poly(ethylene-co-butyl acrylate), long-term performance, ageing, antioxidant, OIT, aqueous media, silanization, irganox 1010, deltamethrin, piperonyl butoxide, chlorine dioxide, migration of stabilizer
National Category
Polymer Technologies
Research subject
SRA - Production
Identifiers
URN: urn:nbn:se:kth:diva-104685ISBN: 978-91-7501-491-3 (print)OAI: oai:DiVA.org:kth-104685DiVA: diva2:566783
Public defence
2012-11-30, Entreplan (F3), Lindstedtsvägen 26, KTH, Stockholm, 13:00 (English)
Opponent
Supervisors
Projects
Cable insulation materialsLoss of deltamethrin and pipronyl butoxide from polyethylenelong-term performance of polyethylene in chlorine dioxide water
Funder
Swedish Research CouncilXPRES - Initiative for excellence in production research
Note

QC 20121109

Available from: 2012-11-09 Created: 2012-11-09 Last updated: 2013-04-19Bibliographically approved
List of papers
1. Preparation and characterization of aluminum oxide-poly(ethylene-co-butyl acrylate) nanocomposites
Open this publication in new window or tab >>Preparation and characterization of aluminum oxide-poly(ethylene-co-butyl acrylate) nanocomposites
Show others...
2012 (English)In: Journal of Applied Polymer Science, ISSN 0021-8995, E-ISSN 1097-4628, Vol. 125, no 2, 975-983 p.Article in journal (Refereed) Published
Abstract [en]

This article describes the preparation and characterization of composites containing poly(ethylene-co-butyl acrylate) (EBA13 and EBA28 with 13 and 28 wt % butyl acrylate, respectively) and 212 wt % (0.53 vol %) of aluminum oxide nanoparticles (two types differing in specific surface area and hydroxyl-group concentration; uncoated and coated with, respectively, octyltriethoxysilane and aminopropyltriethoxysilane). A greater surface coverage was obtained with aminopropyltriethoxysilane than with octyltriethoxysilane. An overall good dispersion was obtained in the EBA-13 composites prepared by extrusion compounding. Composites with octyltriethoxysilane-coated nanoparticles showed the best dispersion. The addition of the nanoparticles to EBA28 resulted in poor dispersion, probably due to insufficiently high shear forces acting during extrusion mixing which were unable to break down nanoparticle agglomerates. The nanoparticles had no effect on the crystallization kinetics in the EBA13 composites, but in the EBA28 composites the presence of the nanoparticles led to an increase in the crystallization peak temperature, suggesting that the nanoparticles had a nucleating effect in this particular polymer.

Keyword
poly(ethylene-co-butyl acrylate), aluminium oxide nanoparticles, nanocomposites, silanization, dispersion, crystallization
National Category
Polymer Chemistry
Identifiers
urn:nbn:se:kth:diva-28775 (URN)10.1002/app.36331 (DOI)000302350300018 ()2-s2.0-84859579887 (Scopus ID)
Funder
Swedish Research Council, IFA 2007-5095
Note
QC 20120508Available from: 2011-01-21 Created: 2011-01-21 Last updated: 2017-12-11Bibliographically approved
2. Antioxidant activity in aluminium oxide - Poly(ethylene-co-butyl acrylate) nanocomposites
Open this publication in new window or tab >>Antioxidant activity in aluminium oxide - Poly(ethylene-co-butyl acrylate) nanocomposites
2012 (English)In: Polymer degradation and stability, ISSN 0141-3910, E-ISSN 1873-2321, Vol. 97, no 6, 1017-1025 p.Article in journal (Refereed) Published
Abstract [en]

The antioxidant activity of Irganox 1010 (0.2 wt%) in aluminium oxide (2-12 wt%) - poly(ethylene-co-butyl acrylate) nanocomposites was studied. The aluminium oxide nanoparticles were in three different forms: uncoated and coated with either octyltriethoxysilane or aminopropyltriethoxysilane. The activity of the stabilizer in the nanocomposites was assessed by determining the oxidation induction time (OIT) using DSC. Composites with untreated aluminium oxide nanoparticles showed a much shorter OIT than the pristine polymer with the same overall antioxidant concentration indicating adsorption of the antioxidant onto the nanoparticle surfaces. The adsorption of antioxidant onto both uncoated and coated nanoparticles was confirmed by X-ray photoelectron spectroscopy. Composites containing coated nanoparticle fillers showed a significantly smaller depression of the OIT, indicating that the replacement of hydroxyl groups with organic silane tails decreased the concentration of available adsorption sites on the particle surfaces. Composites with a filler coated with a silane having terminal aliphatic amine groups showed an increased OIT with respect to that of the pristine polymer suggesting a synergistic on the stability effect between the antioxidant and the amine groups. The long-term activity of the stabilizer was assessed by measuring the OIT on samples after ageing in air at 90°C for 720 h. The decrease in OIT with increasing ageing time of the nanocomposites was slower than for the unfilled polymer. A possible interpretation of these data is that the antioxidant was slowly released from the adsorption sites on extended ageing.

Keyword
Aluminium oxide, Antioxidant, Irganox 1010, Nanocomposites, Poly(ethylene-co-butyl acrylate)
National Category
Polymer Chemistry
Identifiers
urn:nbn:se:kth:diva-96187 (URN)10.1016/j.polymdegradstab.2012.03.012 (DOI)000304641300025 ()2-s2.0-84860385648 (Scopus ID)
Funder
Swedish Research Council, 621-2007-5095
Note

QC 20120531

Available from: 2012-05-31 Created: 2012-05-31 Last updated: 2017-12-07Bibliographically approved
3. Migration of a phenolic antioxidant from aluminium oxide-poly(ethylene-co- butyl acrylate) nanocomposites in aqueous media
Open this publication in new window or tab >>Migration of a phenolic antioxidant from aluminium oxide-poly(ethylene-co- butyl acrylate) nanocomposites in aqueous media
2013 (English)In: Polymer degradation and stability, ISSN 0141-3910, E-ISSN 1873-2321, Vol. 98, no 2, 475-480 p.Article in journal (Refereed) Published
Abstract [en]

The migration of a phenolic antioxidant (Irganox 1010) from nanocomposites based on aluminium oxide (2-12 wt.%; uncoated or coated with aminopropyltriethoxysilane or octyltriethoxysilane) and poly(ethylene-co-butyl acrylate) (EBA) with 13 wt.% butyl acrylate nanocomposites in aqueous media (liquid water or air with 100%RH) at 90°C was studied. The concentration of effective antioxidant in the composites was assessed by the oxidation induction time (OIT) measured by DSC. The flat OIT-profiles through the materials showed that the migration was controlled by the boundary conditions. The boundary antioxidant loss rates to the different media were (in relative units): 1 (dry air; data reported earlier), 1.5-3 (humid air) and 4-10 (liquid water). OIT-profiles for two-layer sandwich samples (a pristine EBA layer and a nanocomposite layer containing 0.2 wt.% Irganox 1010) showed that the antioxidant diffusivity was lowest in the composites containing uncoated nanoparticles (which had the highest surface concentration of hydroxyl groups of all the studied nanoparticles). The presence of water in the composites had only a small effect on the diffusivity; it was 10-50% greater than in the dry systems.

Keyword
Aluminium oxide, Aqueous media, Irganox 1010, Nanocomposite, Poly(ethylene-co-butyl acrylate)
National Category
Polymer Chemistry
Identifiers
urn:nbn:se:kth:diva-104726 (URN)10.1016/j.polymdegradstab.2012.12.016 (DOI)000315131600001 ()2-s2.0-84872105956 (Scopus ID)
Funder
Swedish Research Council, 621-2007-5095
Note

QC 20130215. Updated from submitted to published.

Available from: 2012-11-09 Created: 2012-11-09 Last updated: 2017-12-07Bibliographically approved
4. Migration and chemical consumption of deltamethrin and piperonyl butoxide from polyethylene in aqueous media
Open this publication in new window or tab >>Migration and chemical consumption of deltamethrin and piperonyl butoxide from polyethylene in aqueous media
2013 (English)In: Polymers from Renewable Resources, ISSN 2041-2479, Vol. 4, no 1, 1-18 p.Article in journal (Refereed) Published
Abstract [en]

Deltamethrin (DM), an important insecticide (synthetic pyrethroid) together with synergist piperonyl butoxide (PBO), is used for food storage and insect control purposes. It is often impregnated in polymers for controlled and effective release of insecticide. The migration and chemical consumption of DM and PBO from moulded polyethylene sheets was studied. The thermal behaviour of pristine DM and the prepared polyethylene compound was studied by differential scanning calorimetry. DM did not crystallize and remained in a liquid state after cooling to room temperature. Evaporation rates and activation energies of evaporation were determined by thermogravimetry for pristine DM, PBO, a solution of DM and PBO and for the PE compound. Evaporation from the DM/PBO solution was greater than that predicted from the evaporation rates of the individual compounds, which suggested that the DM/PBO solution obeyed non-ideal solution properties. The migration of DM and PBO from the polyethylene was studied in liquid water at 80 and 95 °C and in air of different relative humidities (60 and 80%) at 80 °C. Exposure to liquid water caused degradation and hydrolysis of the ester bond in DM, present in the prepared material, and generated species containing hydroxyl groups. Liquid chromatography and infrared spectroscopy showed a significant migration of the active species in liquid water, whereas the loss of DM and PBO in air at 80°C (60 and 80 %RH) was negligible over 30 days.

Keyword
Deltamethrin, Piperonyl butoxide., Polyethylene, Pyrethroids
National Category
Polymer Chemistry
Identifiers
urn:nbn:se:kth:diva-104727 (URN)2-s2.0-84876997302 (Scopus ID)
Note

QC 20131125 Updated from submitted to published.

Available from: 2012-11-09 Created: 2012-11-09 Last updated: 2013-11-25Bibliographically approved
5. Assessing the Long-­term Performance of Polyethylene Stabilised WithPhenolic Antioxidants Exposed to Water Containing Chlorine Dioxide
Open this publication in new window or tab >>Assessing the Long-­term Performance of Polyethylene Stabilised WithPhenolic Antioxidants Exposed to Water Containing Chlorine Dioxide
Show others...
2013 (English)In: Polymer testing, ISSN 0142-9418, E-ISSN 1873-2348, Vol. 32, no 2, 359-365 p.Article in journal (Refereed) Published
Abstract [en]

The addition of chlorine dioxide disinfectant to tap water prevents the spread of infection but has a serious drawback in that it degrades materials used in piping, including pipes made of polyethylene. Efficient methods are required to assess the long-term performance of different combinations of antioxidants and polyethylene grades. We have previously presented a screening method which exposes solutions of phenolic antioxidants in squalane (a liquid, low molar mass analogue of polyethylene) to 70 °C water containing either chlorine dioxide or chlorine. This method assesses the stability of the antioxidants towards these aqueous chlorinated media by determining the oxidation induction time through differential scanning calorimetry. The same experimental set-up with two modifications was used in developing a new method. A 0.3 mm thick polyethylene tape replaced the squalane phase and the supply of fresh water containing chlorine dioxide (10 ppm at pH = 6.8) was continuous; this required minimum attention from the operator over the longer exposure time periods used. Tapes of medium-density polyethylene containing 0.1 wt.% of six different phenolic antioxidants were studied. A linear relationship was established between the times to reach antioxidant depletion in the polyethylene tape samples and the times in the squalane samples (with the same antioxidants at the same concentration). A linear relationship was also found between the initial antioxidant consumption rates in polyethylene and squalane. Infrared spectroscopy and scanning electron microscopy of drawn samples revealed the onset of surface oxidation and surface embrittlement in tape samples exposed beyond the time for antioxidant depletion.

Keyword
Polyethylene, Phenolic antioxidants, Chlorine dioxide
National Category
Polymer Chemistry
Identifiers
urn:nbn:se:kth:diva-104734 (URN)10.1016/j.polymertesting.2012.12.003 (DOI)000316513300026 ()2-s2.0-84872131697 (Scopus ID)
Funder
Formas, 245-2007-473
Note

Updated from submitted to published. QC 20130122

Available from: 2012-11-09 Created: 2012-11-09 Last updated: 2017-12-07Bibliographically approved

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