The effect of mold temperature on chemical foaming of injection molded recycled polyethylene-terephthalate

Ronkay, Ferenc; Molnár, Béla; Dogossy, Gábor

doi:10.1016/j.tca.2017.02.013

Cited by 19 publications

(12 citation statements)

References 25 publications

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“…A larger shift is observed for the (100) peak. It can be detected that the crystallite size of samples isotherm crystallized at 423 or 453 K differs significantly from the samples crystallized at 483 K in the direction of D (1)(2)(3)(4)(5)(6)(7)(8)(9)(10) , D (100) and D (101) which may indicate a different nucleation process. Based on the sizes measured for the first three peaks, the crystallites tend to take isometric shape at 488 K, while platy shape is the most characteristic at room temperature.…”

Section: Crystalline Form Analysismentioning

confidence: 95%

“…The usage of poly(ethylene terephthalate) (PET) still increases nowadays; in original form and as secondary raw material alike [1,2]. Besides the packaging industry, PET is increasingly used as a technical material thanks to the achievements of the material developments (Solid State Polycondensation reaction (SSP) or chain extender additives) and the advancements in the processing technologies (foam forming, 3D printing) [3][4][5][6][7]. Regarding applicability of the final products the mechanical properties are crucial, which are greatly affected by the morphology and crystalline structure formed during processing [8,9].…”

Section: Introductionmentioning

confidence: 99%

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Melting temperature versus crystallinity: new way for identification and analysis of multiple endotherms of poly(ethylene terephthalate)

et al. 2020

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Poly(ethylene terephthalate) (PET) materials with different molecular weights were isothermally crystallized from melt by systematically varying the temperature and duration of the treatment performed in the differential scanning calorimeter (DSC). Multiple endotherm peaks were observed on the subsequent heating thermograms that were separated from each other on the basis of their melting temperature versus crystallization temperature and melting temperature versus crystallinity function. By this new approach five sub-peak sets were identified and then comprehensively characterised. Wide-Angle X-Ray Diffraction (WAXD) analyses revealed that the identified sub-peak sets do not differ in crystalline forms. By analysing the crystallinity and the melting temperature of the sub-peak sets as a function of crystallization time, crystallization temperature and intrinsic viscosity, it was concluded that below the crystallization temperature of 460 K the sub-peak sets that were formed during primary or secondary crystallization transform partially or completely to a third sub-peak set during the heating run of the measurement, while above this temperature, the sub-peak set formed during primary crystallization gradually transforms to a more stable structure, with higher melting temperature. These formations and transformations are described with mathematically defined parameters as well.

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Section: Crystalline Form Analysismentioning

confidence: 95%

Section: Introductionmentioning

confidence: 99%

Melting temperature versus crystallinity: new way for identification and analysis of multiple endotherms of poly(ethylene terephthalate)

et al. 2020

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“…2. Measured data points (at 270 °C) and fitted Cross model curves 11 Constants of Cross model for the different materials are summarized in Table 1. It can be concluded, that RPET has the lowest zero shear viscosity value which is due to the shorter molecule chain (lower IV value).…”

Section: Effect Of Chain-extension On Recycled Petmentioning

confidence: 99%

“…Most commercially available PET types have low molecular weight and narrow 3 molecular weight distribution and therefore melt strength is low at foaming temperature resulting in cell collapse [9]. Production of adequate foams is even more challenging if the base material is a small molecular weight recycled PET (RPET) [11] [12].…”

Section: Introductionmentioning

confidence: 99%

Preparation of Low-Density Microcellular Foams from Recycled PET Modified by Solid State Polymerization and Chain Extension

et al. 2018

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Recycled polyethylene-terephthalate (RPET) bottle regrinds were physically foamed after two types of industrially feasible molecular weight increasing processes. Intrinsic viscosity (IV) of initial waste (0.71 dl/g) increased both after reactive extrusion carried out using a multifunctional epoxy-based chain extender (0.74 dl/g) and after solid state polycondensation (SSP) (0.78 dl/g), while capillary rheometry revealed higher degree of branching in the chain extended PET material. Despite the relatively low IV values (below 0.80 dl/g), physical foaming, a mild and cost efficient way, was successful in both cases, uniform microcellular foam structures with void fractions ranging between 75 and 83% were achieved. During the experiments morphology change in the materials was tracked by differential scanning calorimetry (DSC) besides recording IV values. The IV drop during foaming was between 0.03-0.10 depending on the pre-processing technology. Structure of 2 foams produced from the two different modified RPET materials was compared with each other based on scanning electron microscopic imaging (SEM) of cryogenic fracture surfaces.The average cell diameters were measured to be 213 and 360 µm in the case of chain extended and SSP-modified materials, respectively.

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“…An examination for the automotive utilization of the raw material created, taking into account the wreckage directive (ELV Directive 2000/53 / EC). The aim of the research is partly environmental protection and partly the innovative technical raw material production [3].…”

Section: Introductionmentioning

confidence: 99%

Recycling of Mineral Water Bottles with Chemical Foaming

Szabó¹,

Dogossy²

2017

Acta Tech Jaur

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Today, in the field of packaging technologies there is an increasing amount of one-way polymer materials. Such materials after their short lifecycle are disposed, and such pose a serious environmental impact. However, PET is a good quality technical plastic; the recycled use must be provided. In our research, we have examined the recycled material of mineral water bottles. Chemical foaming of recycled polyethylene terephthalate (rPET) was applied for quality increased reusability. Significant results were achieved in terms of mechanical properties at specific mixtures of chain extender and impact resistance enhancer, at the foaming state of the injection moulding.

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The effect of mold temperature on chemical foaming of injection molded recycled polyethylene-terephthalate

Cited by 19 publications

References 25 publications

Melting temperature versus crystallinity: new way for identification and analysis of multiple endotherms of poly(ethylene terephthalate)

Melting temperature versus crystallinity: new way for identification and analysis of multiple endotherms of poly(ethylene terephthalate)

Preparation of Low-Density Microcellular Foams from Recycled PET Modified by Solid State Polymerization and Chain Extension

Recycling of Mineral Water Bottles with Chemical Foaming

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