Crystallization, melting and morphology of syndiotactic polypropylene fractions: 1. Thermodynamic properties, overall crystallization and melting

Rodriguez-Arnold, Jonahira; Zhang, Anqiu; Cheng, Stephen Z. D.; Lovinger, Andrew J.; Hsieh, Eric T.; Chu, Peter P.; Johnson, Tim; Honnell, Kevin G.; Geerts, Rolf G.; Palackal, Syriac J.; Hawley, Gil R.; Welch, M. Bruce

doi:10.1016/0032-3861(94)90978-4

Cited by 83 publications

(104 citation statements)

References 39 publications

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“…As T 0 m of these two fractions were estimated to be 160ЊC, this results in the regime II 3 III transition at the undercooling of 50ЊC, similar to the value estimated by Clark and Hoffman [7]. Based on their earlier value of DH 0 f for 100% crystallinity of 8.0 kJ mol Ϫ1 [20], and T g of 0ЊC [17], they estimated that s is approximately 11.2 erg cm Ϫ2 , s e being in the range of 42.2-47.7 erg cm Ϫ2 , and q being between 4.9 and 5.6 kcal mol Ϫ1 [19,21]. Recently, we [22] also performed a spherulitic growth rate measurement on a s-PP sample of 77.1% syndiotacticity (racemic pentads) over the temperature range of 45-125ЊC.…”

Section: Introductionsupporting

confidence: 84%

“…[19] or s-PP(8) and s-PP(9) in Ref. [20]) in their original publication [19] and only partial data are available in Ref. [21], we obtained their data by back-calculation (using the same parameters as theirs: T 0 m 160ЊC; T g 0ЊC, and DH 0 f 8:0 kJ mol Ϫ1 ) from their results shown as Fig.…”

Section: Theoretical Backgroundmentioning

confidence: 99%

“…It is worth noting that the choice of a 0.1 may be justified for the case of s-PP based on the fact that the s e values estimated by Rodriguez-Arnold et al [19][20][21] based on the modified ThomasStaveley method (using a 0.1) and the Gibbs-Thomson method are comparable within an experimental error. Once s is known, the fold surface free energy s e can be calculated from ss e /s .…”

Section: Theoretical Backgroundmentioning

confidence: 99%

“…Four sets of linear growth rate data for syndiotactic polypropylene spherulites were taken from the literature [17][18][19][20][21][22] (see footnote 1) for re-analysis in this paper. The material characterization data for s-PP samples examined are summarized in Table 1.…”

Section: Materials Linear Growth Rate and Input Datamentioning

confidence: 99%

“…[27] for more details) for a s-PP sample exhibiting 100% syndiotacticity (denoted as T 0 m 100% ), which is 168.7ЊC (441.8 K). The value of DH 0 f is taken as the published value by Rodriguez-Arnold and her coworkers [19][20][21], which is 8.0 kJ mol Ϫ1 (i.e. 1.77 × 10 9 erg cm Ϫ3 ).…”

Section: Materials Linear Growth Rate and Input Datamentioning

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: Introductionsupporting

confidence: 84%

Section: Theoretical Backgroundmentioning

confidence: 99%

Section: Theoretical Backgroundmentioning

confidence: 99%

Section: Materials Linear Growth Rate and Input Datamentioning

confidence: 99%

Section: Materials Linear Growth Rate and Input Datamentioning

confidence: 99%

See 3 more Smart Citations

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

Supaphol

Spruiell

2000

Polymer

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Influence of syndiotacticity and annealing temperature on the double melting peak behaviour of syndiotactic polypropylene

Feng

Liu

et al. 1999

Polym. Int.

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Fractionated syndiotactic polypropylene (sPP) samples with homogeneous tacticity were annealed at different temperatures. The influence of syndiotacticity and annealing temperature on the double melting peak phenomena were investigated. It is found that all fractions show double melting peaks at 75°C annealing temperature, while the low peak disappears when the fractions with higher syndiotacticity are annealed at 85°C and above. The fraction with the lowest syndiotacticity remains the same at any annealing temperature. In combination with wide‐angle X‐ray diffraction experiments, the double peaks are believed to correspond to the melting of cell II and III. The results indicate that higher temperature and syndiotacticity are the external conditions and internal structural factor that permit cell II to transform into cell III. © 1999 Society of Chemical Industry

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Nonisothermal crystallization of s-PP fractions

Feng

Liu

et al. 1999

J. Appl. Polym. Sci.

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Syndiotactic polypropylene (s-PP) was prepared by metallocene catalyst and was fractionated with the temperature rising elution fractionation (TREF) technique. The nonisothermal behavior of the obtained fractions was investigated. Fractions was first cooled at different rates and then heated at a constant rate. The parameters such as the peak crystallization temperature (T c ), the onset crystallization temperature (T on ), the difference between T on and T c (⌬T 1 ϭ T on Ϫ T c ), the crystallization enthalpy (⌬H), the peak melting temperatures (T m1 , T m2 ), and the difference between the T m1 and T m2 (⌬T 2 ϭ T m2 Ϫ T m1 ) were obtained. The dependence of these parameters on cooling rate, syndiotacticity, and molecular weight was discussed. It is found that T c , T on , ⌬H, T m1 , and T m2 systematically increase with increasing syndiotacticity and are depressed on increasing the cooling rate. Cooling rate, syndiotacticity, and molecular weight show different influences on ⌬T 1 . In the melting process of s-PP, double peaks were observed.

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Crystallization, melting and morphology of syndiotactic polypropylene fractions: 1. Thermodynamic properties, overall crystallization and melting

Cited by 83 publications

References 39 publications

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

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

Influence of syndiotacticity and annealing temperature on the double melting peak behaviour of syndiotactic polypropylene

Nonisothermal crystallization of s-PP fractions

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