On the effect of mechanical energy on the degradation of polyethylene in the solid state and in the melt

Holmström, Arne; Andersson, Arne; Sörvik, Erling M.

doi:10.1002/pen.760171006

Cited by 12 publications

(1 citation statement)

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“…However, there are differences of opinion as to which of these degradation mechanism is predominant. Springer et al [ 15 ] and Holmström et al [ 16 ] indicate that thermal degradation is predominant, while Ford et al [ 17 ] and Folt [ 18 ] claim that the main degradation mechanism is mechanical.…”

Section: Introductionmentioning

confidence: 99%

Chemical, thermal, and mechanical properties and ultraviolet transmittance of novel nano‐hydroxyapatite/polyethylene terephthalate milk bottles

Demirel

Inaner

Daver

et al. 2021

Polymer Engineering & Sci

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Polyethylene terephthalate (PET)/nano‐hydroxyapatite (nHAp) composite granules were obtained using twin‐screw extruder. Preforms were prepared by injection molding and then PET/nHAp bottles were produced by blow molding. For PET bottles with nHAp, the migration amounts of carboxylic acid (COOH), acetaldehyde (AA), diethylene glycol (DEG), and isophthalic acid (IPA); glass transition temperature (Tg); melting temperature (Tm); and the maximum crystallization temperature (Tcry) were measured. The load‐carrying capacity, burst strength, stress cracking, and regional material distribution tests were carried out on the bottles. X‐ray diffraction, scanning electron microscopy, Fourier transform infrared spectroscopy, differential scanning calorimetry, and ultraviolet transmittance analyses were conducted to explain the changes in mechanical, chemical, physical properties, and light transmission of bottles. It was found out that the COOH amount increased and the AA content decreased with increasing nHAp amount. On the other hand, no change was observed in the amounts of DEG and IPA. Although the mechanical properties such as load‐carrying capacity and burst strength of the bottles have improved, it has been determined that the standard environmental stress crack resistance test procedure cannot be applied to such a composite. Experimental findings indicate that nHAp disrupts the chemical structure of PET and it isolates harmful chemicals such as AA by forming intermolecular bonds. Moreover, with the addition of up to 0.8% nHAp, PET bottles block the light transmission approximately 80% within 400–700 nm wave length zone. The study demonstrates that the PET/nHAp composite bottles can be used in the food industry, particularly in the packaging of milk and milk products which are vulnerable to light exposure.

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Section: Introductionmentioning

confidence: 99%

Chemical, thermal, and mechanical properties and ultraviolet transmittance of novel nano‐hydroxyapatite/polyethylene terephthalate milk bottles

Demirel

Inaner

Daver

et al. 2021

Polymer Engineering & Sci

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Oxidation of polyethylene in closed mixing chamber

Fodor

Iring

Pukánszky

et al. 1987

Angew. Makromol. Chem.

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The degradation of commercial LDPE was studied under dynamic conditions which simulate the processing. Dynamic oxidation above 140°C is similar to static oxidation under low oxygen pressure both having strong diffusion control. Fragmentation and crosslinking (mainly CC bonds) compete in the process. The hydroperoxides predominate at the beginning of the mixing. Their quantity rapidly decreases while that of oxo groups increases and becomes predominant. Below 140°C, the conditions are resembling to static oxidation performed under higher oxygen pressure but the process is still somewhat diffusion controlled. The change in the molecular mass is not considerable in the process. The hydroperoxides predominate among the functional groups formed. Their ratio is constant during mixing. The effect of mechanical stress is not considerable. An increase in the mixing speed resulted in an increase in the rate of the processes studied above. The higher the total amount of oxygen incorporated in the PE, the smaller is the remaining oxidative stability.

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Troubleshooting Extruders

Rauwendaal

2014

Polymer Extrusion

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On the effect of mechanical energy on the degradation of polyethylene in the solid state and in the melt

Cited by 12 publications

References 11 publications

Chemical, thermal, and mechanical properties and ultraviolet transmittance of novel nano‐hydroxyapatite/polyethylene terephthalate milk bottles

Chemical, thermal, and mechanical properties and ultraviolet transmittance of novel nano‐hydroxyapatite/polyethylene terephthalate milk bottles

Oxidation of polyethylene in closed mixing chamber

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