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Crystallization during polymerization of Lithium Dihydrogen Phosphate. I. Nucleation of the Macromolecular Crystal from the Oligomer Melt
Author(s) -
Benkhoucha R.,
Wunderlich B.
Publication year - 1978
Publication title -
zeitschrift für anorganische und allgemeine chemie
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.354
H-Index - 66
eISSN - 1521-3749
pISSN - 0044-2313
DOI - 10.1002/zaac.19784440129
Subject(s) - nucleation , oligomer , dimer , reaction rate constant , crystallization , polymerization , monomer , crystallography , supercooling , materials science , chemistry , crystal (programming language) , polymer chemistry , thermodynamics , polymer , kinetics , organic chemistry , physics , quantum mechanics , computer science , programming language
By optical microscopy, scanning calorimetry, thermogravimetry, and computer simulation the homogeneous reaction phase and the nucleation of macromolecular crystals of LiPO 3 from the monomeric LiH 2 PO 4 melt was studied. A reaction mechanism is proposed and the concentrations of oligomer species are calculated as a function of time at 276,290, and 300 °C. Rate constants and activation energies are determined. The dimer formation has a rate constant 200 times larger than the rate constant for further oligomerization. The nucleation is athermal and is shown to involve oligomer species of 4.5 nm length or more. The nucleation density was found to be almost constant between 276 and 575°C.