Rapid compression induced solidification of bulk amorphous sulfur

Jia, Ru; Shao, Chunguang; Liu, Su; Huang, D.; Liu, X R; Hong, Shiming

doi:10.1088/0022-3727/40/12/030

Cited by 34 publications

(30 citation statements)

References 20 publications

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“…In numerous research on iPP/CNTs, the common theme focused on was their crystallization behavior under atmospheric pressure [16,17], but less attention was paid to their solidification behavior induced by high pressure, neither is there any report on the effect of pressurization rate on melt solidification. More recently, several studies proved that pressurization is an efficient approach to prepare polymer materials with special performance, such as living polymer sulfur which exhibits exceptional thermodynamic and kinetic stability, glassy polyether-ether-ketone samples possessing excellent friction and considerable stiffness, and the glassy poly (lactic acid) which shows better cold crystallization performance [18,19,20]. Additionally, our recent work indicated the crystal structure and morphology of iPP can be accurately controlled by adjusting pressurization conditions [21], and firstly proved high pressure-annealing can induce meso-γ transformation [22].…”

Section: Introductionmentioning

confidence: 99%

Structure and Mechanical Properties of Multi-Walled Carbon Nanotubes-Filled Isotactic Polypropylene Composites Treated by Pressurization at Different Rates

Jia

Dong

et al. 2019

Polymers

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Isotactic polypropylene filled with 1 wt.% multi-walled carbon nanotubes (iPP/MWCNTs) were prepared, and their crystallization behavior induced by pressurizing to 2.0 GPa with adjustable rates from 2.5 to 1.3 × 104 MPa/s was studied. The obtained samples were characterized by combining wide angle X-ray diffraction, small angle X-ray scattering, differential scanning calorimetry, transmission electron microscopy and atomic force microscopy techniques. It was found that pressurization is a simple way to prepare iPP/MWCNTs composites in mesophase, γ-phase, or their blends. Two threshold pressurization rates marked as R1 and R2 were identified, while R1 corresponds to the onset of mesomorphic iPP formation. When the pressurization rate is lower than R1 only γ-phase generates, with its increasing mesophase begins to generate and coexist with γ-phase, and if it exceeds R2 only mesophase can generate. When iPP/MWCNTs crystallized in γ-phase, compared with the neat iPP, the existence of MWCNTs can promote the nucleation of γ-phase, leading to the formation of γ-crystal with thicker lamellae. If iPP/MWCNTs solidified in mesophase, MWCNTs can decrease the growth rate of the nodular structure, leading to the formation of mesophase with smaller nodular domains (about 9.4 nm). Mechanical tests reveal that, γ-iPP/MWCNTs composites prepared by slow pressurization display high Young’s modulus, high yield strength and high elongation at break, and meso-iPP/MWCNTs samples have excellent deformability because of the existence of nodular morphology. In this sense, the pressurization method is proved to be an efficient approach to regulate the crystalline structure and the properties of iPP/MWCNTs composites.

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Section: Introductionmentioning

confidence: 99%

Structure and Mechanical Properties of Multi-Walled Carbon Nanotubes-Filled Isotactic Polypropylene Composites Treated by Pressurization at Different Rates

Jia

Dong

et al. 2019

Polymers

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“…Molecular dynamics simulations predict that any melt can be solidified to be a fully amorphous solid state under a cooling rate of 10 12 K/s [8]. The cooling rates of common quenching methods are around 10 3 –10 7 K/s [9]. Compression also leads to the solidification of the melts.…”

Section: Introductionmentioning

confidence: 99%

A Study of the Pressure-Induced Solidification of Polymers

et al. 2018

Self Cite

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Abstract:By using a self-designed pressure-jump apparatus, we investigated the melt solidification behavior in the rapid compression process for poly-ethylene-terephthalate (PET), polyetherether-ketone (PEEK), isotactic polypropylene (iPP), high-density polyethylene (HDPE), and the living polymer sulfur. The experimental results clearly show that crystallization could be inhibited, and some melts were solidified to the full amorphous state for PET, PEEK, and sulfur. Full amorphous PEEK that was 24 mm in diameter and 12 mm in height was prepared, which exceeded the size obtained by the melt quenching method. The bulk amorphous sulfur thus obtained exhibited extraordinarily high thermal stability, and an abnormal exothermic transition to liquid sulfur was observed at around 396 K. Since the solidification of melt is realized by changing pressure instead of temperature and is not essentially limited by thermal conductivity, it is a promising way to prepare fully amorphous polymers. In addition, novel properties are also expected in these polymers solidified by the pressure-jump within milliseconds.

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“…The problem of temperature quenching is that there is a temperature and even a cooling rate gradient distribution in the samples, which could induce structure defect of the products . Recently using a high‐pressure jump apparatus, Hong et al have prepared many glassy polymers under a dynamic pressurization process—rapid compressing (RC). Different from the most widely used quench cooling techniques, in RC process the melts are solidified by high pressure jump (pressure of the melt can increase from atmospheric pressure to 2.5 GPa in only 20 ms) rather than temperature drop, so it can get rid of the thermal conductivity limitation of polymer materials and proves effective to prepare amorphous polymer materials in large bulk.…”

Section: Introductionmentioning

confidence: 99%

Cold crystallization behavior of glassy poly(lactic acid) prepared by rapid compression

Zhang

Shao

et al. 2014

Polym Eng Sci

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The cold crystallization behavior of glassy poly(lactic acid) was studied by comparison among samples obtained through three different treatments, which are naturally cooling (NC), liquid nitrogen quenching (NQ), and rapidly compressing (RC). The crystallization kinetics and structural changes of these glassy samples were analyzed by using in situ Fourier transform infrared (FTIR) and in situ wide angle X-ray diffraction measurements. The results reveal that, the cold crystallization behavior is very similar between NC and NQ samples, but RC sample exhibits higher crystallization rate and lower crystallization temperature than them. FTIR investigation showed that, during the heating process for all the glassy samples, conformational adjustment in the amorphous phase occurs first, and followed by formation of the disordered crystals and then the disordered crystals further perfecting, while for RC sample the onset temperature of each step is much lower. Furthermore, for RC sample, the crystal grain number is larger and its initial a 0 form crystal induced by the heating is higher ordered than that of the others, and this unique crystallization behavior might be caused by the local ordered domains formed during the RC process. POLYM. ENG. SCI., 55:359-366, 2015. FIG. 6. Temperature dependence of the FTIR spectra in the 835-980 cm 21 range and the intensity change of indicated bands with temperature during cold crystallization.

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Rapid compression induced solidification of bulk amorphous sulfur

Cited by 34 publications

References 20 publications

Structure and Mechanical Properties of Multi-Walled Carbon Nanotubes-Filled Isotactic Polypropylene Composites Treated by Pressurization at Different Rates

Structure and Mechanical Properties of Multi-Walled Carbon Nanotubes-Filled Isotactic Polypropylene Composites Treated by Pressurization at Different Rates

A Study of the Pressure-Induced Solidification of Polymers

Cold crystallization behavior of glassy poly(lactic acid) prepared by rapid compression

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