Crystallization behaviour of poly( N -methyldodecano-12-lactam) Part 1. Isothermal crystallization

Kratochvíl, Jaroslav; Sikora, Antonín; Baldrián, Josef; Dybal, Jiřı́; Puffr, R.

doi:10.1016/s0032-3861(00)00147-6

Cited by 11 publications

(24 citation statements)

References 15 publications

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“…However, unlike many other polymers showing maximum of crystallization rate at temperatures around the middle of the crystallization window and then decreasing trend as temperature approaches T g , 21 the crystallization rate of MPA, after passing a local minimum at 0°C, increases with decreasing temperature. In our previous study 1 we found that at Ϫ23°C crystallization of MPA was so fast that its kinetics could not be measured. Our recent study of nonisothermal crystallization of MPA 22 has shown that, after cooling to below T g , the subsequent heating runs show crystallization exotherms starting as low as at about T g ϩ 5°C.…”

Section: Primary Crystallization From the Meltmentioning

confidence: 94%

“…Before discussing the results of the additional crystallization kinetics of MPA, we consider it reasonable to briefly sum up which processes, to our knowledge, 1,2 proceed in the system during the first two stages of the complex crystallization of MPA, melt and additional crystallization.…”

Section: Additional Crystallizationmentioning

confidence: 99%

“…1 However, the whole discussion of temperature dependencies of kinetic parameters of additional crystallization is related to the particular primary (melt) crystallization temperatures T c . Thus, the results presented in this article reflect the effect that the conditions of melt crystallization at the given T c have on the course of additional crystallization.…”

Section: Additional Crystallizationmentioning

confidence: 99%

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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: Primary Crystallization From the Meltmentioning

confidence: 94%

Section: Additional Crystallizationmentioning

confidence: 99%

Section: Additional Crystallizationmentioning

confidence: 99%

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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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“…3, the traces of neat PMDL and the two RP samples with the lowest PVPh content show crystallization-melting-recrystallization behaviour typical of PMDL, as discussed elsewhere. 28,29 However, thorough analysis of the DSC traces in Fig. 3 has shown that initial crystallinity of these three samples is negligible.…”

Section: Differential Scanning Calorimetrymentioning

confidence: 96%

“…Just before the DSC measurements, the samples were finally vacuum-dried for 24 h at a temperature set between 80 ∘ C (melting temperature of PMDL +15 ∘ C 28,29 ) and 140 ∘ C (optimum drying temperature of PVPh 27 ), depending on the expected T g value of a particular sample. Neat PMDL and PVPh were treated in the same way.…”

Section: Sample Preparationmentioning

confidence: 99%

Fractional complexation in a miscible polymer blend. Calorimetry and size exclusion chromatography

et al. 2014

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Poly(N-methyldodecano-12-lactam) (PMDL) is miscible with poly(4-vinylphenol) (PVPh). In the system PMDL + PVPh + tetrahydrofuran containing low-molar-mass polymer pair, this miscible blend is soluble in the solvent. In this work, it has been found that the system containing high-molar-mass polymer pair undergoes associative phase separation into a gel-like interpolymer complex and a soluble residual phase (RP). The complex and RP samples were characterized using differential scanning calorimetry, size exclusion chromatography and thermogravimetric analysis. The average molar ratio of PMDL to PVPh in the complex is 1:2, considered an optimum composition of the interpolymer complex. The complex shows higher glass transition temperature and higher thermal stability than the RP. Formation of the interpolymer complex in the studied system and differences in its properties from the RP are caused by higher molar mass/length of associated polymer chains as a result of fractionation during which the high-molar-mass fraction forms the gel-like interpolymer complex and the low-molar-mass fraction forms the soluble RP.

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Crystallization behavior of poly(N‐methyldodecano‐12‐lactam). IV. Nonisothermal crystallization

Kratochvíl

Sikora

2004

J of Applied Polymer Sci

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Nonisothermal crystallization of poly(Nmethyldodecano-12-lactam) (MPA) was investigated using DSC method at cooling rates of 2-40 K/min. With increasing cooling rate, crystallization exotherms decreased in magnitude and shifted toward lower temperatures. Subsequent heating runs (10 K/min) showed an exotherm just above T g , which increased in magnitude with the rate of preceding cooling run, corresponding to the continuation of primary crystallization interrupted as the system crossed T g on cool-

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Crystallization behaviour of poly( N -methyldodecano-12-lactam) Part 1. Isothermal crystallization

Cited by 11 publications

References 15 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

Fractional complexation in a miscible polymer blend. Calorimetry and size exclusion chromatography

Crystallization behavior of poly(N‐methyldodecano‐12‐lactam). IV. Nonisothermal crystallization

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