Molecular weight dependence of the lateral growth rate of polyethylene 2. Folded-chain crystals

Okada, Motoyuki; Nishi, Mutsuo; Takahashi, Masato; Matsuda, Hideomi; Toda, Akihiko; Hikosaka, Masamichi

doi:10.1016/s0032-3861(97)10136-7

Cited by 47 publications

(28 citation statements)

References 8 publications

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“…Such super cooling effect on α is shown in Fig. 19.14 plotted together with the reported reference data, such as PTMPS [6], trans-1,4-polyisoprene (t-PIP) [24], poly(1-butene) (PB-1) [26], POX [27] and PE [28,29]. α decreases clearly with an increase in ∆T .…”

Section: Molecular Weight Dependence Of Crystal Growth Ratementioning

confidence: 68%

“…The large differences in value of α have been reported for a large number of polymers. Hoffman et al [28] and Hikosaka et al [29] have been reported for polyethylene (PE) that α lies in the range of −1.3 to −1.8 at a relatively small super cooling. At a relatively large super cooling, α shows nearly −0.5 [10,11,26,27].…”

Section: Molecular Weight Dependence Of Crystal Growth Ratementioning

confidence: 99%

“…Plots of the reported data for the exponent of power law (α) against supercooling for a various polymers. ✸ PTMPS [6], PESU [18], ✷ t-PIP [24], PB-1 [26], PE [28,29] growth rate can be estimated by the following equation [20,44],…”

Section: Molecular Weight Dependence Of Crystal Growth Ratementioning

confidence: 99%

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Maximum Crystal Growth Rate and Its Corresponding State in Polymeric Materials

Okui

Umemoto

2003

Polymer Crystallization

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Abstract. The temperature dependence of crystal growth rate (G) shows a bell shape with the maximum growth rate G max. The activation energy for the molecular transport in G could be expressed in terms of equation of either Arrhenius or WLF. The G max showed remarkable molecular weight dependence. The plots of G/Gmax against T /Tcmax showed a single master curve without molecular weight dependence. The ratio of Go/Gmax gave a constant value for each polymer. Plots of ln(G/Gmax)/ ln(Go/Gmax) against T /Tcmax for various polymers showed the universal curve. The molecular weight dependence of Gmax was expressed as Gmax ∝ MW α , α was a constant but depending on the morphological features on the crystallization. The value of α was a function of the adsorption mechanism of polymer molecules on the crystal growth front and its diffusion mechanism. The ratio of T cmax/T o m was formulated. Tcmax was also correlated to many other thermodynamic transition temperatures. IntroductionAccording to a classical crystallization theory, a temperature dependence of linear crystal growth rate (G) can be expressed by two exponent factors, such as the molecular transport term (∆E) and the nucleation term (∆F ) [1][2][3]. These two terms have opposing temperature dependence thereby bring about a maximum growth rate (G max ). In fact, many polymeric materials show a bell shape temperature dependence of crystal growth rate, showing the maximum growth rate at T cmax [3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18]. This equation has been applied frequently to data of spherulitic growth rate. Application to the polymer crystallization leads to that the molecular transport term is considerably important in the lower temperature ranges. The transport term can be expressed by either WLF or Arrhenius type. In analyzing the crystallization data in bulk polymers, the WLF expression has been used much familiar than the Arrhenius type, since it has been believed that the former expression fits the data better than the later one. However, the transport term could be sufficiently expressed by the Arrhenius type in polymer crystallization [18][19][20][21]. It is worth to recheck which transport term equation is better describing the temperature dependence of the linear crystal growth rate.On the basis of G max for many crystalline materials, a universal master curve of temperature dependence of crystal growth rate has been proposed by Magill et al. [22,23]. This universal curve comes from a phenomenological basis. The universal master curve is derived from the corresponding state in the growth rate

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Section: Molecular Weight Dependence Of Crystal Growth Ratementioning

confidence: 68%

Section: Molecular Weight Dependence Of Crystal Growth Ratementioning

confidence: 99%

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Maximum Crystal Growth Rate and Its Corresponding State in Polymeric Materials

Okui

Umemoto

2003

Polymer Crystallization

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“…For examples, melt viscosity shows remarkable molecular weight dependence and can be scaled and expressed as a 3.4 power of molecular weight for molecular chains with entanglements. The influence of molecular weight on polymer crystallization rate has been the most interesting subject of various papers [1][2][3][4][5][6][7][8][9][10][11][12][13][14]. Data existing in the literature for spherulite growth rate of several crystalline polymers have been analyzed as a function of molecular weight expressed as a power law of M a .…”

Section: Introductionmentioning

confidence: 99%

“…Data existing in the literature for spherulite growth rate of several crystalline polymers have been analyzed as a function of molecular weight expressed as a power law of M a . For example, the exponent a for poly(ethylene) lies in the range of K1.3 [10] to K1.8 [13] at relatively small super-cooling. On the other hand, for relatively large super-cooling, a is nearly K0.5 [7][8][9]12].…”

Section: Introductionmentioning

confidence: 99%