Role of Crystallinity on Moisture Absorption and Mechanical Performance of Recycled PET Compounds

Negoro, Takanori; Thodsaratpreeyakul, Wiranphat; Takada, Youichiro; Thumsorn, Supaphorn; Inoya, Hiroyuki; Hamada, Hiroyuki

doi:10.1016/j.egypro.2016.05.042

Cited by 26 publications

(20 citation statements)

References 10 publications

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“…Before the actual melting point of the PET recyclates starts at about 250 °C, in the pre-melting region the melting starts beforehand. These peaks can be associated with the melting of smaller or imperfect crystals present on an amorphous region of samples [ 39 , 40 , 41 ], as reported for a peak at 130 °C observed by thermal treatment of PET fibers [ 39 ]. Since the commercial granulates do not show these pre-melting peaks, this can be a result of deficiencies in the drying and consequently a high moisture content as described above.…”

Section: Resultsmentioning

confidence: 95%

Thermal and Mechanical Properties of the Recycled and Virgin PET—Part I

2022

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In various countries, polyethylene terephthalate (PET) represents one of the plastics with a very high recycling rate. Since currently there is no analytical method enabling direct distinction between recycled PET (rPET) and virgin PET (vPET), there are various attempts to differentiate these materials indirectly. One of these approaches claims that the recycling of PET leads to polymer chain degradation, which is reflected in changed thermal, mechanical and crystalline properties, and testing of these properties can therefore be used to distinguish rPET and vPET. However, there are many sources leading to changes in the molecular structure and consequently to the changes of the above-mentioned properties of the PET. The purpose of this study is to analyze the glass transition and melting temperature, degree of crystallinity as well as bending and impact properties of 20 different commercially available PET recyclates from 14 suppliers and evaluate the results with respect to the literature values for vPET. The main results of this study show that the range of vPET properties is so broad that all of the corresponding properties of the tested rPET lie within this range.

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Section: Resultsmentioning

confidence: 95%

Thermal and Mechanical Properties of the Recycled and Virgin PET—Part I

2022

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“…The main thermal parameters were obtained from the second heating runs to remove the thermal history of the pieces. In addition, the bio-PET crystallinity was also calculated by the expression:%χc=(ΔHm−ΔHcc)ΔH100% ·Wp·100 where: %χ c = Degree of crystallinity (%) W p = Weight fraction of bio-PET (%)Δ H m = Melting enthalpy (J·g −1 )Δ H cc = Cold crystallization enthalpy (J·g −1 )Δ H 100% = Melting enthalpy of 100% crystalline PET = 140 J·g −1 [84,85]…”

Section: Methodsmentioning

confidence: 99%

Development of Sustainable and Cost-Competitive Injection-Molded Pieces of Partially Bio-Based Polyethylene Terephthalate through the Valorization of Cotton Textile Waste

Montava-Jordà

Torres‐Giner

Bou

et al. 2019

IJMS

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This study presents the valorization of cotton waste from the textile industry for the development of sustainable and cost-competitive biopolymer composites. The as-received linter of recycled cotton was first chopped to obtain short fibers, called recycled cotton fibers (RCFs), which were thereafter melt-compounded in a twin-screw extruder with partially bio-based polyethylene terephthalate (bio-PET) and shaped into pieces by injection molding. It was observed that the incorporation of RCF, in the 1–10 wt% range, successfully increased rigidity and hardness of bio-PET. However, particularly at the highest fiber contents, the ductility and toughness of the pieces were considerably impaired due to the poor interfacial adhesion of the fibers to the biopolyester matrix. Interestingly, RCF acted as an effective nucleating agent for the bio-PET crystallization and it also increased thermal resistance. In addition, the overall dimensional stability of the pieces was improved as a function of the fiber loading. Therefore, bio-PET pieces containing 3–5 wt% RCF presented very balanced properties in terms of mechanical strength, toughness, and thermal resistance. The resultant biopolymer composite pieces can be of interest in rigid food packaging and related applications, contributing positively to the optimization of the integrated biorefinery system design and also to the valorization of textile wastes.

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“…[41,42] The latter is accomplished on purpose by controlling the extrusion cooling because the presence of moisture could potentially result in a reduction in molar mass through H 2 O-induced backbone degradation during further processing. [5,43,44] On the other hand, the virgin and recycled PET filaments are processed in such a way that they exhibit less semi-crystalline regions to facilitate the 3D printing process (i.e. with regard to flexibility and flow properties).…”

Section: Thermal Characterization Of the Commercial Pet Materialsmentioning

confidence: 99%

Effect of extrusion and fused filament fabrication processing parameters of recycled poly(ethylene terephthalate) on the crystallinity and mechanical properties

Voorde

Katalagarianakis

Huysman

et al. 2022

Additive Manufacturing

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The production of plastic has grown exponentially over the past few decades and with it the amount of plastic waste leaking in the environment, where it fragments into micro-and nanoplastics. This problematic situation stresses the need for increased plastic collection, recycling and reuse rates. Extrusion-based additive manufacturing (AM) and especially fused filament fabrication (FFF) offer an efficient and effective method to reuse and upcycle recycled plastic. This study focuses on poly(ethylene terephthalate) (PET), which has a broad application window and its recycling is therefore environmentally and economically favorable and sustainable. Therefore, this study involves the thermal and mechanical behavior of recycled PET after extrusion and 3D printing. The extrusion parameters are optimized by performing a complete physico-chemical and thermal analysis of the obtained filaments and they were compared with commercial virgin and recycled PET. Moreover, the influence of the applied processing conditions on the degree of crystallinity and mechanical properties is investigated. The filaments are then used for FFF, where various printing parameters are altered to obtain the optimum printing conditions (i.e. printing temperature, the build plate temperature, fan cooling and printing directions). The effect of the degree of crystallinity of semi-crystalline PET is investigated via altered printing parameters, showing superior mechanical properties for an increasing degree of crystallinity. To verify the portability of the obtained optimized print parameters, two different FFF printers are used. The use of recycled PET as feedstock for FFF supports the efforts for improving the sustainability of plastics by valorizing PET waste, and prolonging the lifecycle of PET.

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Role of Crystallinity on Moisture Absorption and Mechanical Performance of Recycled PET Compounds

Cited by 26 publications

References 10 publications

Thermal and Mechanical Properties of the Recycled and Virgin PET—Part I

Thermal and Mechanical Properties of the Recycled and Virgin PET—Part I

Development of Sustainable and Cost-Competitive Injection-Molded Pieces of Partially Bio-Based Polyethylene Terephthalate through the Valorization of Cotton Textile Waste

Effect of extrusion and fused filament fabrication processing parameters of recycled poly(ethylene terephthalate) on the crystallinity and mechanical properties

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