Simulated recycling of post-consumer high density polyethylene material

Boldizar, Antal; Jansson, Anna; Gevert, Thomas; Möller, Kenneth

doi:10.1016/s0141-3910(00)00012-4

Cited by 55 publications

(31 citation statements)

References 5 publications

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“…The almost consistent melt temperature throughout the reprocessing and thermal oxidation of HDPE show that no substantial changes in the mechanical properties should be expected which agrees well with the results from both the tensile test and the melt mass-flow rate measurements, similar to conclusions by Boldizar et al 26 It is plausible that during the reprocessing the free chain ends may rearrange giving a gradual increase in crystallinity. Figure 4 presents the melt temperature of the industrially recycled PP which was similar to the melt temperature of a one time processed PP.…”

Section: 20supporting

confidence: 89%

“…The high oxidation stability of HDPE is in accordance with other studies. 26 The industrially recycled polymers seem to contain lower amount of oxidation indicators, earlier defined. This could be the result of a loss of low molar mass products from the matrix during use and reprocessing of the polymers but in general it is very difficult to draw a conclusion that the real recycled polymers are less affected by the oxidation since the other results show a higher overall degradation.…”

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confidence: 96%

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The design of a test protocol to model the degradation of polyolefins during recycling and service life

Strömberg

Karlsson

2009

J of Applied Polymer Sci

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In terms of the sustainable development for polymeric materials the recovery of plastic waste by means of mechanical recycling is a favorable technique. The largest part of the collected plastic municipal solid waste fraction consists of packaging materials, e.g., polypropylene (PP) and polyethylene. A major drawback to the increased use of recycled polymers is the lack of knowledge about the property changes and the overall quality of the recyclates, e.g., the degree of degradation, mixing, and contamination. This article presents a test protocol for description of the mechanical, physical, and chemical property changes during recycling and service life by combining several reprocessing cycles and thermooxidation. The test protocol was designed to mimic the degradation mechanisms potentially occurring in the materials during the service life and the reprocessing. Virgin PP and HDPE were multiply processed by injection molding. Service life of plastic materials was modeled by accelerated thermal degradation of one time processed materials. Tensile testing, MFR, HT-SEC, DSC, FTIR, and SEM were used to analyze material changes. In parallel, a set of industrially recycled PP and HDPE were also subjected to the same analyses. The results proved that recycled plastics maintain the majority of the material properties even when reprocessed several times. It was demonstrated that the mechanical and thermal properties of PP and HDPE were preserved also after several reprocessing steps. Initiation of degradation was observed for PP but not for HDPE. A decrease in M w of PP from 240,000 to 190,000 (six times reprocessed) was established, this corresponds to an increase in MFR from 8 to 18 g/10 min. By FTIR, it was shown that the carbonyl index increased. The loss of stabilizers affects the properties of the final product. In comparison, industrially recycled PP and HDPE presented to some extent poorer mechanical properties than the materials subjected to model recycling.

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Section: 20supporting

confidence: 89%

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confidence: 96%

The design of a test protocol to model the degradation of polyolefins during recycling and service life

Strömberg

Karlsson

2009

J of Applied Polymer Sci

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“…Another approach to simulate the life cycle of recycled polymeric materials involves the alternate combination of processing (to simulate manufacturing of the product) and accelerated ageing (to simulate the usage phase) in a cyclic procedure; this procedure has been employed to investigate the degradation profiles in HDPE, LDPE, ABS, and PP 11–14. The ageing steps are responsible for a drastic deterioration in the mechanical properties, such as elongation at break, whereas reprocessing steps almost restore the mechanical properties, showing a zigzag‐shaped behaviour during simulated recycling; reprocessing may help to homogenise and dilute the degraded polymer chains and the oxidative moieties formed during ageing and therefore improve the mechanical properties of polymeric wastes 13.…”

Section: Modelling the Degradation Processes Undergone By Recycled Plmentioning

confidence: 99%

Quality Concepts for the Improved Use of Recycled Polymeric Materials: A Review

Vilaplana

Karlsson

2008

Macro Materials & Eng

295

158

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Polymeric waste materials should be considered resources for the manufacture of new products through recycling processes, with a similar status to virgin fossil‐based plastics and biopolymers from renewable resources. Several efforts can be made to achieve this qualitative quantum leap in plastics recycling, and consequently introduce recycled products, with competitive performance, to the market. Scientific knowledge about the degradation processes during the life cycle and the development of fast and reliable analytical methods for the quality assessment of recycled plastics are fundamental to guarantee their performance in new applications. Different strategies—restabilisation, rebuilding, compatibilisation, and addition of elastomers and fillers—can be used to upgrade the structure and properties of polymeric waste streams. This review discusses recent developments in the mechanical recycling of plastics, focusing on how to produce quality materials from waste streams and, thus, contribute to a sustainable management of resources and energy.magnified image

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“…There have been a number of studies report on the processability and performance of recycled polymers, but most works are focused on recycling of polyolefin [1][2][3][4][5][6][7] and polyester [8][9][10][11] due to large amount of disposal. It is rather well known how these materials behave during recycling and how their properties are affected by repeated processing.…”

Section: Introductionmentioning

confidence: 99%

Influence of reprocessing on the mechanical properties and structure of polyamide 6

Lin

2007

Journal of Materials Processing Technology

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Simulated recycling of post-consumer high density polyethylene material

Cited by 55 publications

References 5 publications

The design of a test protocol to model the degradation of polyolefins during recycling and service life

The design of a test protocol to model the degradation of polyolefins during recycling and service life

Quality Concepts for the Improved Use of Recycled Polymeric Materials: A Review

Influence of reprocessing on the mechanical properties and structure of polyamide 6

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