Solvent-Induced Crystallization in Poly(ethylene terephthalate) during Mass Transport:  Mechanism and Boundary Condition

Abstract

The mechanism of mass transport and the related crystallization in poly(ethylene terephthalate) (PET) were studied. Solvent-induced crystallization can occur during the transport process in PET at low temperature. The important effect of changing the surrounding medium to solvent molecules is to reduce the glass transition temperature. This phenomenon is called “plasticization”. The extent of plasticization relies on the amount of solvent around the polymer molecules, i.e., the concentration of solvent which will depend on the mass transport before saturation. Evidences for the transport mechanism in the first stage of crystallization were revealed. The distinct diffusion front was determined from the measurements of optical microscope and microhardness. The differential scanning calorimeter (DSC) curves displayed crystallization exothermic peaks whose areas decreased with the amounts of amorphous regions, representing the solvent-induced crystallization (SINC) process. The observed phenomenon of multiple-stage crystallizations is associated with the variation of boundary conditions during mass transport, which was ignored in most theoretical analyses.

Crystallization of Amorphous Poly(Lactic Acid) Induced by Vapor of Acetone to Form High Crystallinity and Transparency Specimen

“…A relationship between conducting time (square root of the time) and crystallization front (length from edge of the specimen to crystallization front) is shown in Figure 6. The plot clears that diffusion distance of acetone is in proportion to square root of the exposed time, indicating the diffusion of acetone vapor in PLA obeys Fick type diffusion [30][31][32]. These results show good agreement with the results of the PLA crystallization immersed in acetone solvent.…”

Crystallization of amorphous poly(lactic acid) induced by organic solvents

“…The plot clears that permeation distance of acetone is in proportion to square root of the immersion time, indicating that the permeation obeys Fick type diffusion. [33][34][35] The same experiment was conducted at 40 C and 50 C, and the results are plotted in Figure 3. The rate of the permeation of acetone increased with increasing of the conducted temperature.…”

“…Permeation of acetone into the amorphous phase of PET promoted the crystallization of PET. [33][34][35] We applied the crystallization method to PLA and found that the crystallization was induced by some organic solvents, especially acetone. In this article, we investigated the solvent induced crystallization of amorphous PLA and its properties precisely, and found out that the acetone not only induced crystallization but also played a role of a plasticizer…”

Crystallization of poly(ethylene terephthalate) filaments by infusion of ethanol upon cold drawing

“…Organic solvent can induce crystallization in PET polymer at low temperature by plasticizing effect. The extent of plasticization depends on the amount of solvent that has penetrated inside the polymer [2,4]. Some papers have reported that amorphous PET can be crystallized by immersion in selected organic solvents (i.e.…”