Study of the degradation mechanisms of polyethylene during reprocessing

Mendes, Ausenda; Cunha, António M.; Bernardo, C. A.

doi:10.1016/j.polymdegradstab.2011.02.015

Cited by 73 publications

(51 citation statements)

References 15 publications

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“…The changes are likely related to the long chain branching and crosslinking of the material, discussed in the previous paragraph. Similar observations have been reported by others …”

Section: Resultssupporting

confidence: 93%

Detergent impurity effect on recycled HDPE: Properties after repetitive processing

Mylläri

Hartikainen

Poliakova

et al. 2016

J of Applied Polymer Sci

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High density polyethylene (rHDPE) is extruded 1 to 8 times, with and without detergent, to simulate the effects of impurities on the material and on the artificial ageing process. The mechanical properties, thermal stability, rheology, Fourier transform infrared spectroscopy (FTIR), and volatile organic compound (VOC) emissions are measured. According to the results, ageing of rHDPE increases tensile strength, reduces elongation, and enhances side chain branching of the material and thus causes rheological changes. The addition of detergent reduces changes in mechanical properties and rheological behavior but accelerates thermal degradation. VOC and FTIR measurements of the samples with detergent addition show generation of harmful 1,4‐dioxane. The amount of total emission, as well as emissions of important perfumes limonene and 1R‐α‐pinene, decreases during multiple extrusion cycles. Heating of the plastics is found to be a major factor in the VOC emission reduction. Impurities have a notable effect on the artificial ageing results. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 43766.

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“…The changes are likely related to the long chain branching and crosslinking of the material, discussed in the previous paragraph. Similar observations have been reported by others …”

Section: Resultssupporting

confidence: 93%

Detergent impurity effect on recycled HDPE: Properties after repetitive processing

Mylläri

Hartikainen

Poliakova

et al. 2016

J of Applied Polymer Sci

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“…It increased from about 4.5% up to 7.8% after the 7th cycle. Neat HDPE has previously been characterized by Mendes et al In that study, it was observed that the elongation, on the contrary, decreased with increased number of injection moulding cycles. This was interpreted as an increase of cross‐links with increasing number of processing cycles.…”

Section: Resultsmentioning

confidence: 78%

“…There is a trend toward lower specific gravity as the number of processing steps increase. Mendes et al studied repeated injection moulding of HDPE and measured the density after each step . A slight reduction of the density was found in that study.…”

Section: Resultsmentioning

confidence: 83%

Recycling of wood fiber‐reinforced HDPE by multiple reprocessing

Åkesson

Fuchs

Stöss

et al. 2016

J of Applied Polymer Sci

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The mechanical recycling of high-density polyethylene (HDPE) reinforced with wood fiber was studied by means of repeated injection moulding. The change in properties during the recycling was monitored by tensile and flexural tests, Charpy impact tests, differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), FTIR spectroscopy, and by measuring the fiber lengths. Tests were also done where injection moulding was combined with subsequent accelerated thermo-oxidative ageing and thereafter repeated numerous times. The results showed that the HDPE composites were relatively stable toward both the ageing conditions and the repeated injection moulding. The change of the mechanical properties was mainly observed as an increased elongation at max.

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“…As shown in Fig. , the MFI of PP keeps constant over four reprocessing cycles and then slightly increases until the sixth cycle, which indicates that PP has good thermal stability. Either HDPE or LDPE has around 70% of reduction in the MFI after six reprocessing cycles, showing a poor thermal stability.…”

Section: Degradation Crystallization and Processability Of Polyolefmentioning

confidence: 77%

Mechanical reprocessing of polyolefin waste: A review

Yin

Tuladhar

Shi

et al. 2015

Polymer Engineering & Sci

137

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Efficient technology and applications for recycled polymer waste has become increasingly important to decrease environmental contamination and to conserve nonrenewable fossil fuels. Mechanical recycling is the most widely practiced in Australia, since it is relatively easy and economic; and moreover, infrastructure for collection and reprocessing has been well established. In order to improve quality of end products of recycled plastics, various workable reprocessing techniques in the second stage of mechanical recycling have been developed and widely applied in the recycling industry. This article critically reviews the current reprocessing techniques of recycled polyolefins. Reprocessing recycled polyolefins is always accompanied with degradation, crystallization, and consequent processability problems, which result from molecular chain scission, branching, and crosslinking. The present state of knowledge and technology of various reprocessing techniques, including melt blending, filler reinforcement and mechanochemistry, is then described and evaluated systematically. Each reprocessing technique presents its own individual advantages and special applications. POLYM. ENG. SCI., 55:2899-2909, 2015

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Study of the degradation mechanisms of polyethylene during reprocessing

Cited by 73 publications

References 15 publications

Detergent impurity effect on recycled HDPE: Properties after repetitive processing

Detergent impurity effect on recycled HDPE: Properties after repetitive processing

Recycling of wood fiber‐reinforced HDPE by multiple reprocessing

Mechanical reprocessing of polyolefin waste: A review

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