A heterogeneous model for the thermal oxidation of solid polypropylene from chemiluminescence analysis

Celina, Mathias C.; George, Graeme A.

doi:10.1016/0141-3910(93)90138-9

Cited by 115 publications

(40 citation statements)

References 30 publications

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“…In the corresponding curve for HDPE, no significant changes in the Young modulus could be detected, Figure 1(b). In general, the degradation is heterogeneous, [13][14][15][16] which gives difficulties interpreting the analyses results. In Figure 1(b), this is significant, as a wide spreading in the measured modulus is observed for all reprocessed samples.…”

Section: Resultsmentioning

confidence: 97%

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: Resultsmentioning

confidence: 97%

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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“…Therefore, some local areas exhibit higher degrees of oxidation than others [112]. A series of mechanistic models and considerations have been published that refer to the polymer oxidation as a fundamentally inhomogeneous process [113,114].…”

Section: Test Methods To Evaluate Polymer Thermal Oxidative Stabilitymentioning

confidence: 99%

Antioxidants

Kröhnke

Schacker

Zäh

2015

Ullmann's Encyclopedia of Industrial Chemistry

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“…The chemiluminescence emission can be related to the hydroperoxide (POOH) content, since generation of peroxy radicals depends on the peroxide concentration formed during processing or in-service life of the material under ambient conditions [17]. As peroxide species are the primary oxidation intermediates of the polyolefin degradation, CL can be used to evaluate the degree of degradation [10], to study the reaction mechanisms [18] and oxidation kinetics [19,20], or to assess the stabilization efficiency of additives [21,22].…”

Section: Introductionmentioning

confidence: 99%

Chemiluminescence studies on comparison of antioxidant effectiveness on multiextruded polyethylenes

Sánchez

Allen

Liauw

et al. 2015

Polymer Degradation and Stability

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a b s t r a c tSeveral polyethylene resins; high density polyethylene (Ph-HDPE, Phillips metal oxide catalyst) and linear low density polyethytlenes (LLDPE, formed using ZieglereNatta catalyst and metallocene catalyst technology, m-LLDPE) were used in order to acquire an insight in to the effect of different polymerization catalyst systems on the melt stabilization performance of single AO. Chemiluminescence (CL) and melt flow rate (MFR) were used to analyze the degradation as a function of the number of passes through a twin-screw extruder. A good correlation was obtained, and the additives resulting with the best melt flow stability in the polymer were the same as those that promote the best CL results.

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A heterogeneous model for the thermal oxidation of solid polypropylene from chemiluminescence analysis

Cited by 115 publications

References 30 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

Antioxidants

Chemiluminescence studies on comparison of antioxidant effectiveness on multiextruded polyethylenes

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