Cocrystallization of poly(vinylidene fluoride) and vinylidene fluoride-tetrafluoroethylene copolymers: 1. Effect of chain structure and crystallization conditions

Datta, Jhunu ; Nandi, Arun K. (1994) Cocrystallization of poly(vinylidene fluoride) and vinylidene fluoride-tetrafluoroethylene copolymers: 1. Effect of chain structure and crystallization conditions Polymer, 35 (22). pp. 4804-4812. ISSN 0032-3861

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Official URL: http://www.sciencedirect.com/science/article/pii/0...

Related URL: http://dx.doi.org/10.1016/0032-3861(94)90736-6

Abstract

Poly(vinylidene fluoride) and vinylidene fluoride-tetrafluoroethylene copolymers cocrystallize depending on the structures present in each. In the α-phase, the maximum difference in the defect concentration of the two polymers (Δ defect) equals 12.3% during isothermal crystallization, and is equal to 10.5% when the system is quenched. In the β-phase, it is 11.8% for isothermal crystallization, and ˜5.5% when quenched. Apart from isomorphic cocrystallization between components of the same polymorph, cocrystal formation between the α- and β-polymorphs was also observed. The resulting cocrystal adopts the structure of a particular polymorph, according to the results obtained from potential energy calculations. The interplanar spacings (dhkl) of the α-phase of PVF2 do not change with the H-H defect concentration, but for the β-phase d200 increases with the defect concentration. The reason for this difference in behaviour has been attributed to the more compact nature of the β-polymorph unit cell, when compared to that of the α-polymorph. The limiting value of the Δ defect for cocrystallization in the α-phase has been attributed to the larger difference in the intramolecular potential energy, whereas that of the β-phase has been attributed to the compact nature of the unit cell.

Item Type:Article
Source:Copyright of this article belongs to Elsevier Science.
Keywords:PVF2; VF2-VF4 Copolymers; Cocrystallization
ID Code:85371
Deposited On:02 Mar 2012 05:18
Last Modified:02 Mar 2012 05:18

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