Real time optical and mechano-optical studies during drying and uniaxial stretching of Polyetherimide films from solution

Abstract

a b s t r a c tIn order to have a fundamental understanding of the temporal evolution of physical characteristics of Polyetherimide (PEI) film and processing parameters, real time measurements are essential. Because drying and stretching processes of solvent-cast polymer film are complex, off line measurements are unable to reveal the temporally varying detailed information, especially for fast "transient events". To solve the problem, two measurement systems, one for drying that tracks real time thickness, weight, surface temperature, in-plane and out-of-plane birefringence of solution casting film, and another for uniaxial stretching that tracks real time true stress, true strain and birefringence of stretched film are used. By using these systems, we are able to systematic investigate the development of optical anisotropy through in and out of plane birefringence monitoring drying of solution cast films and their mechanooptical behavior during stretching, and quantify the influence of solvent N-methyl-2-pyrrolidinone (NMP) on these relationships.

Mechano‐opticalbehavior in poly (ethylene terephthalate)/poly (ether imide) blends

“…They concluded that at all rates the apparent demarcation from linearity in the strain optical constants corresponds to approximately 1.2 times the T g of PLA 13 . Jiang et al 39 showed the temporal evolution of physical characteristics of solution cast noncrystallizable polyetherimide films by uniaxial stretching. They found that initial linear elastic regime shrinks with the increase of solvent content indicating that the presence of solvents partially “melts” these rigid segmental correlations in T g –T ll range.…”

Poly(cannabinoid)s: Hemp-Derived Biocompatible Thermoplastic Polyesters with Inherent Antioxidant Properties

“…Beyond a critical drying level, it rapidly increases to a high value around 10 min. These results on in-plane and out-of-plane birefringence indicate that the initially randomly oriented polymer chain axes lay down in the plane randomly as the thickness decreases during solvent evaporation . Thus, dried films attain uniaxial symmetry with optic axes oriented in the normal direction.…”

“…Figure 1a plane and out-of-plane birefringence indicate that the initially randomly oriented polymer chain axes lay down in the plane randomly as the thickness decreases during solvent evaporation. 30 Thus, dried films attain uniaxial symmetry with optic axes oriented in the normal direction. The films were found to be amorphous as the aromatic groups and side groups designed in this polymer make it easy to vitrify even when solidified from highly mobile solutions.…”

“…Solution-cast films were dried in the chamber of a real-time measurement system described in detail elsewhere. , This system measures weight, thickness, and in/out-of-plane birefringence of cast solution on a glass substrate with controlled airspeed and temperature. The air temperature can be adjusted from room temperature to 200 °C, and airspeed can vary from 0 to 4.5 m/s.…”