The Rate of Crystallization of Linear Polymers with Chain Folding

Hoffman, John D.; Davis, G. T.; LauritzenJr., John I.

doi:10.1007/978-1-4684-2664-9_7

Cited by 708 publications

(618 citation statements)

References 153 publications

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“…In the context of the LH secondary nucleation theory [1][2][3][4][5][6][7][8][9][10], the linear growth rate G of a crystalline aggregate (e.g. spherulite or axialite) for each regime is dependent on the degree of undercooling, DT, and is defined by the following equation:…”

Section: Theoretical Backgroundmentioning

confidence: 99%

“…the LH secondary nucleation theory) has been developed and revised repeatedly in subsequent publications essentially by Hoffman and his co-workers [4][5][6][7][8][9][10]. The theory suggests that polymers crystallize in three different regimes, as opposed to the classical theory of secondary nucleation in which the deposition of a single nucleus on a growth face is followed by a rapid lateral spreading process.…”

Section: Introductionmentioning

confidence: 99%

“…Based on the growth rate studies in various laboratories, the presence of a regime I 3 II transition has been observed in polyethylene [4], and poly(l-lactic acid) [11]. Regime II 3 III transitions have been observed in polyethylene [6], isotactic polypropylene (i-PP) [7], and poly(oxymethylene) [12].…”

Section: Introductionmentioning

confidence: 99%

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Regime crystallization in syndiotactic polypropylenes: re-evaluation of the literature data

Supaphol

Spruiell

2000

Polymer

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The Lauritzen and Hoffman secondary nucleation theory was applied to linear growth rate data of syndiotactic polypropylene taken from the literature. Observation of the distinctive upward change of slope in plots of log G ϩ U ‫ء‬ /2.303R(T c Ϫ T ∞ ) versus 1/2.303T c (DT)f suggested the regime II 3 III transition at the crystallization temperature of 110ЊC. Based on the input parameters judged to be the most accurate, the ratios of K g,III /K g,II were found to range from 1.7 to 2.2. Regardless of the crystal structure, if the growth is assumed to occur on the bc plane, the lateral surface free energy, s 11.3 erg cm Ϫ2 and the fold surface free energy s e 63.7^7.1 erg cm Ϫ2 were found. The latter leads to the average work of chain folding of q 7:4^0:8 kcal mol Ϫ1 . If the growth is assumed to occur on the ac plane, the fold surface free energy is found to be s e 82.4^9.1 erg cm Ϫ2 , while the lateral surface free energy is the same as previously noted. In this case, the work of chain folding of q 9:6^1:1 kcal mol Ϫ1 is found. These values are applicable to both regimes II and III. A detailed evaluation of the effects of changes in input parameters was also carried out. ᭧

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Section: Theoretical Backgroundmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Regime crystallization in syndiotactic polypropylenes: re-evaluation of the literature data

Supaphol

Spruiell

2000

Polymer

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“…Remarkably, crystals do indeed form in spite of such topological frustrations. A rich phenomenology of polymer crystallization has been cultivated over the past seven decades, with numerous sets of experimental data posing challenges for full interpretation [1][2][3][4][5][6][7][8][9][10][11][12][13]. As a prominent feature of the phenomenon of polymer crystallization, polymer crystals form as thin lamellae with thickness in the 10 nm range and lateral dimensions in microns or larger.…”

mentioning

confidence: 99%

“…The free energy (5) is minimized for δφ δω. In the model we consider, we ignore the coupling (5) for reasons discussed in §2. These have to do with the high free energy cost of a disclination (see §2) in the displacement field, and are of special significance for the tent morphology of polymer crystallites (see §5).…”

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confidence: 99%

Stability of the sectored morphology of polymer crystallites

2016

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Dual melting endotherms in the thermal analysis of poly(ethylene terephthalate)

Qiu

Tang

Huang

et al. 1998

J. Appl. Polym. Sci.

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A modified mathematical model based on the melting and recrystallization of an initial distribution of melting temperatures satisfactorily predicts the melting behavior of PET in differential scanning calorimetry. The simulated DSC curves produced in this work agreed fairly well not only with experimental DSC curves performed by Holdsworth et al., but also with the DSC traces provided by SSP PET pellets. The model, taking into account the initial distribution of melting points and the distribution of melting points for the recrystallized material, succeeded in analyzing the origin of dual endotherms of PET with various thermal histories, thereby elucidating the effect of changing crystallization temperature and time, the heating rate in the DSC heating scan, as well as the SSP process on the melting behavior of PET completely. Furthermore, it has been analytically proven that the crystallinity measured on a DSC diagram could not be equal to the weight percentage of crystalline state in the initial specimen. The deviation of the measured crystallinity, as observed relevant to the melting and recrystallization processes, is caused by the changes of the heat of fusion with the melting temperature as well as the difference of heat capacities of liquid and solidstate polymer.

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The Rate of Crystallization of Linear Polymers with Chain Folding

Cited by 708 publications

References 153 publications

Regime crystallization in syndiotactic polypropylenes: re-evaluation of the literature data

Regime crystallization in syndiotactic polypropylenes: re-evaluation of the literature data

Stability of the sectored morphology of polymer crystallites

Dual melting endotherms in the thermal analysis of poly(ethylene terephthalate)

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