The deformation behavior of polypropylene film under high strain rates

Abstract

The relationship between stress and strain for polypropylene film was studied under strain rates from 0.13 to 5.21 s 21 in order to study the deformation behavior of film under higher strain rates than previous studies. Uniform thickness was obtained in the strain rates from 2.08 to 5.21 s 21 at 435 K, or from 2.08 to 3.13 s 21 at 437 K. The temperature rise of film due to the generation of heat from plastic strain influenced the relationship between stress and strain, in particular, at high strain rates and low temperature. Material constants for the constitutive equation of film were determined using the measurements from 2.08 to 5.21 s 21 at 435 K and from 2.08 to 3.13 s 21 at 437 K. Film thicknesses during and after transverse direction stretching were successfully predicted by applying the material constants obtained. The authors concluded that the material constants should be determined by applying the stretching conditions, under which there is little or no effect from heat generation and under which film can be stretched uniformly in thickness. POLYM. ENG. SCI., 53:309-320, 2013. ª

The Sequential Analysis of Film Deformation Behavior during Successive Biaxial Stretching Process

“…A constitutive equation expressed as equation ( 1) is employed for film under the assumption that the deformation of film obeys a rigid-plastic rule. This assumption provided good results for the prediction of the thickness of film in the previous studies [2].…”

“…Operation conditions such as temperature and stretching ratio on this process must be optimized in order to produce the film with a satisfactory quality. The authors have been analyzed the deformation behavior of film during MD [1] or TD stretching [2]. MD and TD stretching, however, are needed to be analyzed sequentially in order to optimize the operation conditions on successive biaxial stretching process.…”

Structural Formation of Cyclic Olefin Copolymer (COC) Films as Revealed by Real Time Retardation Measurements during Fast Stretching Process

“…Kikutani et al [8] examined the retardation of PET running filaments at higher strain rates of up to 1 m/s in investigations of the relationship between birefringence and stress/temperature. Studies of PP film deformation behavior under fast stretching by Tokihisa et al [9] focus on uniformity of thickness as another important quality of stretched films. Hong and White [10] investigated the birefringence of cyclo olefin polymer (COP) filaments under melt spinning and their mechanical properties.…”