Accession Number : AD0681504

Title :   THE EFFECTS OF THE QUANTITY AND PLACEMENT OF COPOLYMER UNITS WITHIN THE POLYMERIC CHAIN ON THE CRYSTALLIZATION phenomena in polymers. PART III.

Descriptive Note : Technical rept. 1 May 67-31 Aug 68,

Corporate Author : FLORIDA STATE UNIV TALLAHASSEE

Personal Author(s) : Mandelkern,Leo

Report Date : OCT 1968

Pagination or Media Count : 38

Abstract : The relations between the dissolution temperature, the crystallite thickness, and the crystallization temperature of linear polyethylene fractions crystallized from dilute solution are reported. The data are analyzed using equilibrium dissolution temperatures independently determined from investigations of the solubility properties of the bulk crystallized polymer which are also described. The interfacial free energy associated with the 001 basal plane, characteristic of the mature crystallites, differs from that involved in nucleation. From the most general considerations of nucleation theory, it is concluded that the interfacial structure of the nucleus is significantly different from that of the mature crystallite that develops from it. It is also established that the crystallite thickness is nucleation controlled, although details of the nucleation process itself and of the chain structure within the nucleus cannot be uniquely specified. Results on the thermodynamic and morphological properties of ordered copolymers of polyethylene oxide and poly-d, 1-propylene oxide crystallized from the melt and from dilute solution are reported. (Author)

Descriptors :   (*POLYETHYLENE PLASTICS, *SOLUBILITY), CRYSTALLIZATION, CRYSTAL LATTICES, SOLUTIONS(MIXTURES), NUCLEATION, OXIDES, FREE ENERGY, POLYMERS

Subject Categories : Physical Chemistry

Distribution Statement : APPROVED FOR PUBLIC RELEASE