In situ FTIR spectroscopic study on crystallization process of isotactic polystyrene

Kimura, Tsunehisa; Ezure, Hidetoshi; Tanaka, Sakuya; Ito, Eiko

doi:10.1002/(sici)1099-0488(199805)36:7<1227::aid-polb12>3.0.co;2-a

Cited by 47 publications

(41 citation statements)

References 5 publications

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“…[113][114][115][116][117][118][119][120][121] Because the conformation of the mesophase differs from the crystalline state or the amorphous state, 45 its formation could be detected by means of in-situ FT-IR measurements. In fact, FT-IR observation of the conformation change of polyethylene that occurs prior to the crystallization is reported.…”

Section: Infrared Spectroscopic Analysis Of Mesophasementioning

confidence: 97%

“…118 Also, in-situ FT-IR measurements during crystallization are reported for PEN 120 and iPS. 121 In order to monitor the occurrence of mesophase of PEN, we started with identification of the bands specific to this phase. For this purpose, we prepared a few samples obtained under extremely different thermal conditions, that is, one that encourages high crystallinity (crystallization for a prolonged time), and the other that encourages highly amorphous phase (quenching from a melt).…”

Section: Infrared Spectroscopic Analysis Of Mesophasementioning

confidence: 99%

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Study on the Effect of Magnetic Fields on Polymeric Materials and Its Application

Kimura

2003

Polym J

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236

206

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ABSTRACT:This paper reviews our recent work on the use of magnetic fields to the polymer processing. Polymers considered in this paper are not peculiar ones synthesized specially for the purpose of magnetic processing, but they are very usual ones including poly(ethylene terephthalate), polypropylene, etc. In this paper, two main magnetic effects on polymers are considered, i.e., alignment and levitation. In the first part, the magnetic torque causing the alignment is described. Then, examples of alignment in polymeric systems are presented, starting from simple cases such as magnetic alignment of fibers in a suspension to more complicated cases such as magnetic alignment of crystalline polymers in which mesophase formations and memory effects are involved. In the second part, the magnetic force acting on diamagnetic materials and its application to separation and processing of polymeric materials is described.KEY WORDS Diamagnetism / Magnetic Alignment / Magnetic Levitation / Phase Transition / Crystalline Polymers / Polymer Processing / Fiber / Magnetic effects on diamagnetic materials have been known since the age of Faraday, but it is very recent that the attention has been paid to the use of these effects to the processing of diamagnetic materials including inorganic, organic, and polymeric materials. This trend is partially due to the development of superconducting technology 1 that enables us to use high magnetic fields (10 T or more) in the study of materials science at individual laboratory level. Cryogen free (liquid-helium free) superconducting magnets, mostly manufactured by Japanese companies, are now on the market, with various types including a large bore type (45 cm at 3.5 T), a rotate bore type, a split type, a low fringe field type, a high field type (15 T, 52 mm in diameter), etc. These magnets are used in academia as well as industries for the processing purposes.High magnetic fields provided by these superconducting magnets have made it possible to visualize the magnetic effects on "non-magnetic" materials such as diamagnetic materials. Because the diamagnetism is very small compared to the ferromagnetism, we hardly experience in daily life the effects of magnetic field on plastics, water, and living bodies, etc. Some means must be devised to visualize these effects. A straightforward way is to use high magnetic fields. If we use a superconducting magnet of 10 T instead of an electromagnet generating 1 T, a small change of 1 mm is magnified to 10 cm and a phenomenon that takes a day to occur is completed in 15 min, because the magnetic effect is proportional to the square of the magnetic flux density. Diamagnetic levitation 2-4 and Moses effect 5 (water surface splits in a high magnetic field) are good examples among many others. [6][7][8][9] The magnetic effect on chemical reactions 10-12 is one of the major fields in magnetic researches, but in this paper we are concerned with the magnetic force and the magnetic torque acting on diamagnetic materials. The origin of the diamagnetism is the ...

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Section: Infrared Spectroscopic Analysis Of Mesophasementioning

confidence: 97%

Section: Infrared Spectroscopic Analysis Of Mesophasementioning

confidence: 99%

Study on the Effect of Magnetic Fields on Polymeric Materials and Its Application

Kimura

2003

Polym J

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236

206

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“…Upon cooling down to the crystallization temperature T c (< T m ), crystallization starts but no crystals form during the initial stage of crystallization (induction period). Spectroscopic studies on isotactic polystyrene (iPS) 4) and poly(ethylene-2,6-terephthalate) (PEN) 5) indicate that mesophase forms and/or develops in the induction period. In-situ magnetic birefringence observation and the X-ray diffraction measurement for quenched samples of PEN, 6) iPS, 7) and PET 8) indicate that the magnetic alignment of the mesophase occurs during the induction period.…”

Section: Preferential Alignment Modelmentioning

confidence: 97%

“…This change could occur in association with the mesophase formation. Both for iPS 4) and PEN, 5) mesophase formation is observed during the induction period, prior to the formation of crystals. These experimental evidence might support the present model that assumes the mesophase.…”

Section: Preferential Alignment Modelmentioning

confidence: 99%

Phase Transformation of Polymeric Materials in High Magnetic Field

Kimura

2003

Mater. Trans.

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A model to describe a non-rotation type magnetic alignment of crystalline polymers during crystallization from melts is presented. The model is based on the presence of mesophase existing between the melt phase and the crystalline phase, with an extremely small transformation enthalpy and a resultant large shift of melting point in the presence of a magnetic field. A calculation of the magnetic effect on the nucleation and growth rates of mesophase is carried out. It is shown that these rates are enhanced for the mesophase with a specific orientation with respect to the applied field, resulting in alignment.

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“…[1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18] Recent studies on the crystallization of unoriented poly(ethylene terephthalate (PET) [1][2][3][4] and poly(ethylene naphthalate) (PEN) 5 have shown the existence of a transient mesophase in the nucleation stage prior to crystallization. Imai et al studied the crystallization of PET in the unoriented form and found that a long range ordered structure is formed in the induction period before crystallization.…”

Section: Introductionmentioning

confidence: 99%

Structure formation during isothermal crystallization of oriented isotactic polystyrene

Radhakrishnan

Dikshit

Kaito

2000

J. Polym. Sci. B Polym. Phys.

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In situ FTIR spectroscopic study on crystallization process of isotactic polystyrene

Cited by 47 publications

References 5 publications

Study on the Effect of Magnetic Fields on Polymeric Materials and Its Application

Study on the Effect of Magnetic Fields on Polymeric Materials and Its Application

Phase Transformation of Polymeric Materials in High Magnetic Field

Structure formation during isothermal crystallization of oriented isotactic polystyrene

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