Thermal stability, crystallization kinetics and morphology of a new semicrystalline polyimide based on 1,3-bis(4-aminophenoxy) benzene and 3,3′,4,4′-biphenyltetracarboxylic dianhydride

Ratta, Varun; Ayambem, A.; Young, R. T.; McGrath, James E.; Wilkes, Garth L.

doi:10.1016/s0032-3861(00)00125-7

Cited by 36 publications

(43 citation statements)

References 21 publications

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“…14 A relatively often ascertained n value of about 2.5 is explained by simultaneous occurrence of two-and three-dimensional crystal growth, including formation of a sheaflike structure during early stages of crystallization. [13][14][15] The Avrami exponent was also found to be temperature dependent. The increase in n values with decreasing crystallization temperature is explained by greater involvement of homogeneous nucleation at higher supercoolings 15,16 or by multidimensional growth.…”

Section: Introductionmentioning

confidence: 90%

Crystallization behavior of poly(N‐methyldodecano‐12‐lactam). III. Kinetics of isothermal crystallization

Kratochvíl

Sikora

2004

J of Applied Polymer Sci

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Differential scanning calorimetry, combined with Avrami theory, was used to investigate the kinetics of three steps of the complex crystallization process of poly(Nmethyldodecano-12-lactam) (MPA): (1) primary melt crystallization at respective crystallization temperature (T c ), (2) additional crystallization at 30°C, and (3) recrystallization at 54°C. Kinetics of the three steps was discussed with respect to T c . The Avrami exponent n of primary melt crystallization decreased between 2.5 and 1.9 in the range of T c values of Ϫ10 to 20°C, which suggests heterogeneous nucleation, followed by two-dimensional growth, with a larger involvement of homogeneous thermal nucleation at greater supercoolings. The crystallization rate constant k decreased with increasing T c . The value of n ϭ 1.5 for additional crystallization implies a two-dimensional diffusion-controlled crystal growth with a suppressed nucleation phase. For T c values ranging from Ϫ10 to 0°C and 0 to 20°C, k showed weak and quite strong decreasing dependencies on T c , respectively. The recrystallization mechanism involved partial melting of primary crystallites and two-dimensional rearrangement of chains into a more perfect structure. The rate of this process was almost independent of T c . The values of activation energies were derived for the three steps of MPA crystallization using the Arrhenius equation.

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Section: Introductionmentioning

confidence: 90%

Crystallization behavior of poly(N‐methyldodecano‐12‐lactam). III. Kinetics of isothermal crystallization

Kratochvíl

Sikora

2004

J of Applied Polymer Sci

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“…[1][2][3] Concurrently, another class of thermoplastic PIs has also been developed, which can crystallize from the melt, including LARC-CPI (Langley research center crystalline polyimide), [4,5] LARC CPI-2 (Langley research center crystalline polyimide -second generation), [6] PI-2 (3,3,4,4 0 -benzophenonetetracarboxylic dianhydride and 2,2-dimethyl-1,3-(4-aminophenoxy)-propane), [7] TPI (thermoplastic polyimide), [8][9][10] TPEQ-ODPA (1,4-bis(4-aminophenoxy)benzene and 4,4 0 -oxydiphthalic anhydride), [11] and TPER-BPDA (1,3-bis-(4-aminophenoxy)benzene and 3,3 0 ,4,4 0 -biphenyltetracarboxylic dianhydride). [12] A specific feature of these PIs is their ability to crystallize from the melt to form crystalline matrices for composite materials. This feature distinguishes them from other semicrystalline PI matrices of the LARC-TPI-type that melt in the temperature range 270-290 8C but do not recrystallize spontaneously upon cooling.…”

Section: Introductionmentioning

confidence: 99%

The Nucleating Effect of Carbon Nanotubes on Crystallinity in R‐BAPB‐Type Thermoplastic Polyimide

Yudin

Svetlichnyi

Shumakov

et al. 2005

Macromol. Rapid Commun.

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Summary: The relatively high degree of crystallinity of a new thermoplastic polyimide (PI) makes it a favorable matrix candidate for fiber reinforced composites. This advantage is the result of the ability of the matrix to recrystallize during the composite manufacturing process. In this study we examine the potential nucleating effect of carbon nanotubes on a thermoplastic PI. In addition to their inherent mechanical contribution, the carbon nanotubes help recover a significant proportion of the original crystallinity.Scanning electron micrograph of the spherulitic structure of a recrystallized carbon nanotube/polyimide film.magnified imageScanning electron micrograph of the spherulitic structure of a recrystallized carbon nanotube/polyimide film.

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“…The high crystallinity of polyimide BTDA/MPDA without side chains was confirmed by wide-angle Xray diffraction, and the presence of sharp and wellresolved peaks is consistent with the well-organized spherulitic morphology obtained through POM. The introduction of side chains significantly reduced the degree of crystallinity of polyimides, and BTDA/ PP0DA, BTDA/PP2DA, and BTDA/PP6DA showed only a broad crystalline peak at about 23° (2). The introduction of side chains also changed the crystalline structure of polyimide.…”

Section: Effect Of Side Chains On the Phase Structure Of Polyimidesmentioning

confidence: 99%

Introduction of side chains containing biphenyl unit on the crystalline morphology and properties of polyimides

Liu

Tang

Wang

et al. 2006

J of Applied Polymer Sci

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Several polyimides derived from 3,3Ј,4,4Ј-benzophenonetetracarboxylic dianhydride (BTDA) and 3,5-diaminobenzate containing various side chains with biphenyl unit through various flexible spacer were prepared by thermal imidization. By incorporating side chains, the solubility was greatly enhanced and all the polyimides with side chains showed good solubility in polar solvents. During a continuous thermal imidization procedure, the BTDA/ MPDA polyimide samples formed a novel banded spherulites with not only zigzag Maltese crosses, but also distinct extinction rings, while the polyimides with side chains revealed only fine grainy crystalline particle. X-ray diffraction of BTDA/MPDA powder showed sharp diffraction peak in the X-ray diffraction and revealed the existence of highly ordered crystalline structure in polyimide, while BTDA/ PP0DA, BTDA/PP2DA, and BTDA/PP6DA polyimides with side chains revealed only a broad reflection at the low angle and demonstrated the presence of low-ordered layer structure. DSC confirmed that the introduction of side chains significantly reduced the melting points of the resulted polyimide, thus it greatly enhanced its thermal plasticity. However, the heat-resistant properties such as the thermal stability were generally decreased, and all the polyimide with side chains showed a typical two-step thermal degradation behavior relating to the pyrisis of side chains and polyimide backbone.

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Thermal stability, crystallization kinetics and morphology of a new semicrystalline polyimide based on 1,3-bis(4-aminophenoxy) benzene and 3,3′,4,4′-biphenyltetracarboxylic dianhydride

Cited by 36 publications

References 21 publications

Crystallization behavior of poly(N‐methyldodecano‐12‐lactam). III. Kinetics of isothermal crystallization

Crystallization behavior of poly(N‐methyldodecano‐12‐lactam). III. Kinetics of isothermal crystallization

The Nucleating Effect of Carbon Nanotubes on Crystallinity in R‐BAPB‐Type Thermoplastic Polyimide

Introduction of side chains containing biphenyl unit on the crystalline morphology and properties of polyimides

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