Some studies of the crystallization of polychlorotrifluoroethylene copolymer films

Abstract

A fluorocarbon copolymer of chlorotrifluoroethylene (96%) and vinylidene fluoride has been isothermally crystallized and the quenched films analyzed by the light microscope, photographic light‐scattering, and density measurements. Above a supercooling of 79°C., homogeneous nucleation dominates, giving a morphology that appears to be that of a twisted ribbon. At supercoolings below 79°C., heterogeneous nucleation dominates and leads to spherulitic morphology. Sheaf or rodlike morphology occurs at very low supercoolings. Crystallization rates determined from density measurements at room temperature indicate maximum rate due to heterogeneous nucleation occurring at a supercooling greater than 79°C., but the temperature for maximum rate cannot be identified because of the transition to homogeneous nucleation which causes a discontinuity in the rate versus temperature curve. Superposability of crystallization isotherms constructed from density values are inconsistent with the large melting point lowering from that of polychlorotrifluoroethylene for this copolymer. However, this may be explained by the presence of a different crystal system for each monomer in the copolymer.

Mechanical properties and microstructure of polychlorotrifluoroethylene toughened by polyamide 11 based on intermolecular interaction

“…The crystalline morphology of all specimens observed by POM are shown in Figure 6. The neat PCTFE specimen crystallizes in rod‐shaped crystals as previous reports 45 . After introducing PA11, the size of PCTFE crystal reduces apparently, confirming that PA11 could be a nucleating agent for PCTFE.…”

“…The neat PCTFE specimen crystallizes in rod-shaped crystals as previous reports. 45 After introducing PA11, the size of PCTFE crystal reduces apparently, confirming that PA11 could be a nucleating agent for PCTFE. The crystalline grain refining is beneficial to the promoting toughness.…”

Light scattering of bisphenol-A polycarbonate in the amorphous state and at the beginning of thermal crystallization

“…Because of the very large amount of scattering, these measurements were made on films, 100-300 #m thick, using the photographic technique described by Adams and Stein (42).…”

(Co)polymers of Chlorotrifluoroethylene: Synthesis, Properties, and Applications

“…Below 79 °C, heterogeneous nucleation dominates and a spherullic morphology is obtained. 74 The less crystalline materials are optically clear, tough, and ductile as well as being endowed with higher elasticity and lower modulus. On the other hand, the more crystalline ones are less transparent, with high tensile modulus and less elongation.…”

“…In the case of a copolymer of CTFE (96 mol %) and VDF (4 mol %), the structure looks like a twisted ribbon after cooling at temperatures above 79 °C, whereas the nucleation is mostly homogeneous. Below 79 °C, heterogeneous nucleation dominates and a spherullic morphology is obtained . The less crystalline materials are optically clear, tough, and ductile as well as being endowed with higher elasticity and lower modulus.…”