Influence of supercritical CO2 and initial melting temperature on crystallization of polypropylene/organoclay nanocomposite

Svoboda, Petr; Trivedi, Krunal; Svobodová, Dagmar; Kolomaznı́k, Karel; Inoue, Takashi

doi:10.1016/j.polymertesting.2012.01.004

Cited by 6 publications

(3 citation statements)

References 19 publications

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“…The results showed that a better dispersion of the MMT in PET matrix was obtained. For the same purpose, processing aids such as high energy ultrasound , electrical fields and supercritical fluids were performed. Among them, the usage of supercritical fluids, especially supercritical carbon dioxide (scCO 2 ), has proved to be an alternative route for preparation of PCNs, overcoming some of the issues of using conventional method .…”

Section: Introductionmentioning

confidence: 95%

Enhanced dispersion of nanoclays in poly(ethylene terephthalate)/clay nanocomposites using supercritical carbon dioxide

Xie

Qin

et al. 2016

Vinyl Additive Technology

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Nanoclays were prepared using supercritical carbon dioxide (scCO 2 ) as a medium, and then blended with polyethylene terephthalate (PET) via conventional melt blending processing. The structure and morphology of nanoclays were investigated using wide-angle X-ray diffraction (WAXD) and scanning electron microscopy (SEM). It was found that, compared with the original organically modified layer silicates, smaller nanoclay tactoids and individual platelets morphology could be obtained after they were processed by scCO 2 , indicating scCO 2 processing could enhance exfoliation of nanoclays. WAXD and transmission electron microscopy measurements were used to evaluate the dispersion of nanoclays in the nanocomposites. The results indicated the conventional blending extrusion processing could help to improve the dispersion of nanoclays, and the nanocomposites containing scCO 2 pretreated nanoclays formed a looser clay stack and an improved intercalation structure, compared with those containing as-received nanoclays. Thermal and mechanical properties of the nanocomposites were also studied by differential scanning calorimetry (DSC) and dynamic mechanical analysis, and the results showed that crystallization rate, crystallinity, and storage modulus of the well-dispersed nanocomposites containing scCO 2 pretreated nanoclays were increased, compared with the neat PET and nanocomposites containing asreceived nanoclays or nanoclays prepared by conventional organomodification process in water. J. VINYL ADDIT. TECHNOL., 23:E58-E67, 2017.

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Section: Introductionmentioning

confidence: 95%

Enhanced dispersion of nanoclays in poly(ethylene terephthalate)/clay nanocomposites using supercritical carbon dioxide

Xie

Qin

et al. 2016

Vinyl Additive Technology

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“…PP is being also used for microcellular injection moulding applications allowing the fabrication of lightweight parts for the automotive sector. However, it has been reported that mixing PP with super critical fluids has impact on the crystallization process of PP [50][51][52][53][54][55]. This paper proposes a numerical model integrating microcellular injection moulding simulations and a crystallization mathematical model to critically estimate PP phase change in the cooling stage and to study how MuCell ® process parameters influence the crystallization process.…”

Section: Introductionmentioning

confidence: 99%

Investigation on the Crystallization Process of Microcellular Injection Moulded Parts and the Influences of Parameters on the Crystallization by Simulation

Ding,

Yang,

Bakker

et al. 2023

Preprint

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Crystallization, as a physical transformation process, plays an important role on the final properties of a plastic part. Similar to other injection moulding processes, injection and cooling conditions in microcellular injection moulding (e.g. MuCell® process) determine the phase change transformation of the material (molten to solid) and consequently, nucleation, crystal growth and crystallinity. The crystallization process of microcellular injection moulded parts has been mainly investigated using laborious and time-consuming experimental characterization techniques, but no studies reported the use of numerical methods to estimate the crystallization process. This paper presents a mathematical model successfully used to simulate the crystallization process of microcellular injection moulded parts. Microcellular injection moulding was simulated using Moldex 3D, and the crystallization process was investigated using the Hoffman nucleation theory for the crystal nucleation rate, the Lauritzen-Hoffman growth theory for the crystal growth rate, and the Avrami model to calculate the relative crystallinity. Numerical simulations allowed to investigate the effect of key processing parameters (melt temperature, mould temperature, flow rate, gas dosage amount and shot volume) on the crystallization process. Moreover, the numerical model was validated considering published experimental data.

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“…The variations in the morphology of poly(L‐LA‐ ran ‐VL) under scCO 2 were evaluated for using as controlled‐release materials. In order to investigate the effects of scCO 2 treatment on the thermal properties, degree of crystallinity, and molecular motions, many researchers have reported using poly(lactide). Previous research projects have examined changes in the thermal properties, degree of crystallinity and molecular stretching and bending of poly(lactide) before and after scCO 2 processing, and have shown correlations between these parameters.…”

Section: Introductionmentioning

confidence: 99%

Changes in the morphology of poly( l ‐lactide‐ ran ‐δ‐valerolactone) following supercritical carbon dioxide processing

Tsutsumi

Ishikawa

Takahashi

et al. 2019

Polymer Crystallization

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Biodegradable polymers can be employed as controlled‐release materials when processed with supercritical carbon dioxide (scCO2), and l‐lactide (L‐LA) random copolymers are useful in such applications. In the present work, poly(l‐lactide‐ran‐δ‐valerolactone) (poly(L‐LA‐ran‐VL)) copolymers, which do not melt during scCO2 processing above 80°C, were synthesized. The thermal properties, crystallinity, and polymer chain structures of these materials were evaluated before and after processing at temperatures from 60°C to 120°C and 14 MPa. An efficient one‐pot process (termed azeotropic‐combined one‐pot polymerization or ACOP) produced poly(L‐LA‐ran‐VL) or poly(L‐LA) in good yields and high molecular weights, and poly(L‐LA) with an Mn of 8.20 × 104 was obtained without the use of an inert gas. Poly(L‐LA‐ran‐VL) composed a 73/27 ratio of L‐LA and VL had a relatively high molecular weight despite its lower L‐LA content, and its Tm and ΔHm were decreased only slightly compared to that of poly(L‐LA). Both ΔHm and crystallinity were found to increase with increases in the scCO2 processing temperature, especially at 120°C. Although the degree of crystallinity increased with increasing L‐LA content, the ΔHm of the 83/17 specimen (which had the lowest Mn) was higher than that of the 91/9 sample. Before processing, the 73/27 copolymer had the highest haze value while the 91/9 specimen had the lowest, and there was a linear relationship between the haze and crystallinity of each copolymer after processing at all temperatures. The infrared spectrum of the 73/27 copolymer prior to scCO2 processing exhibited a maximum absorbance at 1756 cm−1, and this peak was shifted to higher wavenumber with increases in the processing temperature. Thus, infrared spectroscopy could be used to assess increases in crystallinity following scCO2 processing.

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Influence of supercritical CO2 and initial melting temperature on crystallization of polypropylene/organoclay nanocomposite

Cited by 6 publications

References 19 publications

Enhanced dispersion of nanoclays in poly(ethylene terephthalate)/clay nanocomposites using supercritical carbon dioxide

Enhanced dispersion of nanoclays in poly(ethylene terephthalate)/clay nanocomposites using supercritical carbon dioxide

Investigation on the Crystallization Process of Microcellular Injection Moulded Parts and the Influences of Parameters on the Crystallization by Simulation

Changes in the morphology of poly( l ‐lactide‐ ran ‐δ‐valerolactone) following supercritical carbon dioxide processing

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