Hydrolysis etching of crystalline and amorphous poly(ethylene terephthalate): Influence of molecular weight and microstructure

Calleja, F. J. Baltá; Cagiao, M. E.; Zachmann, H. G.; Vanderdonckt, C.

doi:10.1080/00222349408248096

Cited by 11 publications

(5 citation statements)

References 7 publications

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“…Similar to the results for storage moduli, it can be said that the decrease in complex viscosity of PET with incorporation of IO nanoparticles was due to hydrolysis, decreasing the molecular weight of PET in the presence of Fe 2+ as an impurity of the IO nanofiller. [15,16] The values of η 0 , using the η * values of ω = 0.1 Hz, approximately, for PET/IO nanocomposites against nanofiller concentration are presented in the graph of Fig. 6 for more convenience.…”

Section: Melt Dynamic Rheometrymentioning

confidence: 99%

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The Ability of Rheological Studies for Assessment of Hydrolysis During Processing of Polyethylene Terephthalate Nanocomposites

Ebadi‐Dehaghani

Hassanzadeh

Ansari

2014

Journal of Macromolecular Science, Part B

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Hydrolysis of poly(ethylene terephthalate) (PET) during processing in the presence of Fe 2 O 3 (ferrite) nanoparticles (IO) was investigated.Three nanocomposites, filled with 2.5, 5, and 10 wt.% of IO nanoparticles, were processed in the melt state at 260 • C. A nanocomposite containing 5 wt% of nano-silica was also prepared similarly as the blank sample. Dynamic mechanical thermal properties of the nanocomposites showed that, while the introduction of SiO 2 nanoparticles increased the glass transition temperature (T g ) of PET, incorporation of IO nanoparticles led to a decrease in T g . There was an increase in rheological storage modulus (G ) of PET with incorporation of SiO 2 nanoparticles in the low-frequency region. Conversely, the incorporation of IO nanoparticles led to a decrease in G in this frequency region. The decrease of G was attributed to hydrolysis of PET due to the presence of impurities in the IO. The zeroshear rate viscosity (η 0 ) increased with incorporation of SiO 2 nanoparticles. Conversely, this value decreased with incorporation of IO nanoparticles. While rheological studies showed a significant decrease in molecular weight of the PET due to hydrolysis, the IR spectroscopy did not have sufficient ability for assessment of the hydrolysis phenomenon. However, the viscosity-average molecular weight (M v ) measurements showed that the molecular weight decrease found via rheological studies was in good accordance with theM v values.

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Section: Melt Dynamic Rheometrymentioning

confidence: 99%

“…[15,16] . Several cations, such as Fe 2+ , Co 2+ , Mg 2+ , etc., have been reported to catalyze the degradation of the polymer chains and affect the molecular weight and also the molecular weight distribution (MWD).…”

Section: Introductionmentioning

confidence: 99%

The Ability of Rheological Studies for Assessment of Hydrolysis During Processing of Polyethylene Terephthalate Nanocomposites

Ebadi‐Dehaghani

Hassanzadeh

Ansari

2014

Journal of Macromolecular Science, Part B

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“…This implies that even low amounts of water can impart significant degradation levels in PET, depending on temperature conditions. According to the literature, the maximum temperature to which PET can be submitted without instantaneous conversion is 225 C (Mancini 2001), although considerable hydrolysis occurred at 180 C (Calleja et al 1994). Nevertheless, preliminary studies have shown that the intrinsic viscosity of PET is maintained at 0.60 dl g À1 for short time intervals at temperature as high as 170 C. It defined a narrow sub-critical condition range, which could be explored vis-a-vis a physical recycling process for PET.…”

Section: Introductionmentioning

confidence: 99%

Evaluation of sub-critical water as an extraction fluid for model contaminants from recycled PET for reuse as food packaging material

Santos

Agnelli

Manrich

2010

Food Additives & Contaminants: Part A

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Recycling of plastics for food-contact packaging is an important issue and research into meaningful and cost-effective solutions is in progress. In this paper, the use of sub-critical water was evaluated as an alternative way of purifying poly(ethylene terephthalate) (PET) flakes for direct food contact applications. The effects of temperature, pressure and flow rate were assessed on the extraction efficiency of two of the most challenging classes of contaminants (toluene and benzophenone) from PET by sub-critical water using a first-order fractional experimental design. Extraction yield was quantified using GC/FID. The most important parameter was flow rate, indicating that the decrease in sub-critical water polarity with temperature was insufficient to eliminate partition effects. Temperature was also important, but only for the optimization of toluene extraction. These results may be explained by the poor solubility of higher molar mass compounds in sub-critical water compared to lower molar mass compounds under the same conditions, and the small decrease in dielectric constant with temperature under the experimental conditions evaluated. As cleaning efficiency is low and PET is very susceptible to hydrolysis, which limits the use of higher temperatures vis-a`-vis physical recycling, the proposed extraction is unsuitable for a standalone super-clean process but may be a step in the process.

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“…Nowadays, there are some patents related to the PET and water reactions, at temperatures above the polymer melting point (10)(11) , employing extrusion as well (12) . Important literature may be found on hydrolysis of PET in solid state, too, which focuses the study of the reaction as a degrading process in order to identify the influence of exposing PET for long periods to humid atmospheres on the eventual processing of the polymer (1)(2)(13)(14)(15)(16) . These studies presented low reactions velocities, however much higher than the oxidative and thermal degradation velocity of PET.…”

Section: Introductionmentioning

confidence: 99%

Optimization of Neutral Hydrolysis Reaction of Post-consumer PET for Chemical Recycling

Mancini

Zanin

2004

Progress in Rubber, Plastics and Recycling Technology

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The neutral hydrolysis reaction of post-consumer poly(ethylene terephthalate) in solid state was studied through the reaction of the polymer with water at the molar ratio 1:91 with autogenous pressure. Two sizes of post-consumer PET flakes and temperatures of 135°C, 170°C and 205°C with pressures of 4.0 atm, 7.5 atm and 13.5 atm, respectively, were considered. With reaction time equal to 6h, the method reached 99% depolymerization at 205°C, 8.2% at 170°C and 1.7% at 135°C. The reaction extension was measured by separating the terephthalic acid formed in the process and calculating by gravimetry how much material could still be reacted. Through the viscosimetry of diluted solutions and the counting of carboxylic end groups in the remaining material from the gravimetric assay, it was possible to suggest that the reaction occurs randomly and in the whole volume of the polymeric particle and not solely on the surface. The terephthalic acid obtained and then purified was characterized by elemental analysis, magnetic nuclear resonance, size and particle size distribution and spectrophotometry in the visible spectrum, and it was similar to the petrochemical equivalent, with purity recorded in carbon base equal to 99.9%.

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Hydrolysis etching of crystalline and amorphous poly(ethylene terephthalate): Influence of molecular weight and microstructure

Cited by 11 publications

References 7 publications

The Ability of Rheological Studies for Assessment of Hydrolysis During Processing of Polyethylene Terephthalate Nanocomposites

The Ability of Rheological Studies for Assessment of Hydrolysis During Processing of Polyethylene Terephthalate Nanocomposites

Evaluation of sub-critical water as an extraction fluid for model contaminants from recycled PET for reuse as food packaging material

Optimization of Neutral Hydrolysis Reaction of Post-consumer PET for Chemical Recycling

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