Drawing Forces and Film Properties in Semi-Sequentially Stretched Polypropylene

Abstract

The relationship between biaxial stretching and oriented polypropylene film properties is studied. Initial films have been made with a 6 Â 6 areal draw ratio (ADR) while reducing the transverse direction (TD) drawing speed and maintaining the machine direction (MD) speed. Slowing the TD speed increases the final TD drawing force and produces anisotropic film shrinkage. Varying the draw ratios in both directions creates anisotropic tensile properties. By changing both drawing speeds and draw ratios, films with similar shrinkage but differing tensile properties have been made.

Paper-reinforced sodium alginate/carboxyl methyl cellulose-based bio-composite films

“…However, at the same time, the film flexibility is not compromised due to this impermeability. As per earlier studies, 8 the WVTR values of this film are almost four order higher than of typical polypropylene film.…”

“…Conventional biaxially oriented polypropylene packaging films have strength between 100 and 200 MPa. 7,8 The principle research work performed here was developing paperreinforced sodium alginate/NaCMC bio-composite films with potential applications, where moderate level of mechanical strength is required. Optimizing sodium alginate/NaCMC polymer ratio with incorporating paper to reinforce the polymer matrix and after-treatment with alum solution and its effect on mechanical, barrier, and thermal properties were evaluated.…”

“…Conventional biaxially oriented polypropylene packaging films have strength between 100 and 200 MPa. 7,8…”

The deformation behavior of polypropylene film under high strain rates

“…Polypropylene (PP), for example, is well studied from many points of view, such as the characterization and the modeling of macroscopic deformation behavior of film using a uniaxial or biaxial stretcher [ 1–4], the observation, measurement, and modeling of the evolution of higher order structure during stretching [5–11], and the characterizing of stretched film [5, 12–17] have been conducted. Most of them, however, are basic studies because the phenomena during the TD stretching process are very complicated and experimental study using a pilot plant is expensive.…”

“…Most of the results in previous studies, however, were based on measurements under relatively low or moderate strain rates. For example, for PP it was 2.0 s −1 in the work by Jabarin [ 3], 0.37–2.3 s −1 in the work by Sweeney et al [4], 0.001–0.17 s −1 in the work by Koike and Cakmak [8], 0.01–0.5 s −1 in McLeod [16], and 1.68 s −1 in the previous study [34] by the present authors. These strain rates were lower than the strain rate in the industrial process for BOPP.…”