Investigation on the Tensile Behavior and Morphology Evolution of Isotactic Polypropylene Films Polymerized with Different Ziegler-Natta Catalysts

Abstract

Stereodefect distribution is very important in determining the morphology and properties of isotactic polypropylene (iPP). In this study, two iPPs (PP-A and PP-B) with different uniformities of stereodefect distribution were prepared. The tensile behavior and morphology evolution of their cast films were studied. The morphology study of the cast films showed that compared with PP-B, PP-A with less uniform distribution of stereodefects has smaller spherulites and spheruilitic boundaries and higher degree of crystallinity. In uniaxial tensile measurements, PP-A exhibited higher yield strength and lower elongation at break. When strain was 500%, PP-A exhibits totally transparent appearance and highly oriented structures without cavities, whereas PP-B shows opaque appearance and mass of both nanometer-and micrometer-sized cavities. Moreover, calculation of rigid amorphous fraction (RAF) indicated that PP-B cast film has a higher amount of RAF, which might be the reason for the different morphology evolutions and tensile behaviors of the samples. C 2015 Wiley Periodicals, Inc. Adv Polym Technol 201 , , 21573; View this article online at wileyonlinelibrary.com.

The effect of flexible sealing jaws on the tightness of pouches made from mono‐polyolefin films and functional papers

“…The onset temperature measured for this laminate at 143 C gives an indication of starting melt flow and interdiffusion at the seal surface 6. Comparable results for onset and melting temperature were reported for a CPP layer by Kang et al3 However, this temperature setting still leads to considerable shrinkage. Tightness of paper materials from labsealed samples The rhodamine test results of the paper-based materials do not deliver any tight sealed sample with flat profile (Figure 11, left).…”

“…An alternative to the PE sealant layer is a cast polypropylene (CPP). The CPP is sealable but exhibits an almost similar onset and melting temperature at around 165°C 3 as it is known for instance for BOPP 4 . It is also known that the orientation of the OPP is relaxed within temperatures above 150°C 5 .…”

The sealing behavior of new mono‐polyolefin and paper‐based film laminates in the context of bag form‐fill‐seal machines

“…Kang et al 16 report an onset temperature of 155.8°C and 152.7°C and a similar melting temperature of 162.9°C for two CPP grades (measured by DSC). This melting temperature is very close to the expected melting temperature of the OPP carrier material for which the data of 17 delivers an indication with 163°C–165°C (measured at BOPP).…”

Effects of Polypropylene Orientation on Mechanical and Heat Seal Properties of Polymer-Aluminum-Polymer Composite Films for Pouch Lithium-Ion Batteries

“…The Herman orientation function of this vibration was obtained according to the method of Tabatabaei et al [ 27 , 28 ]: where D is the ratio of the absorption parallel and absorption perpendicular to the machine direction. For polypropylene, absorption at the wave number of 998 cm −1 is attributed to the crystalline phase ( c axis) whereas absorption at the wave number of 972 cm −1 is due to the contribution of both crystalline and amorphous phases.…”

“…Moreover, since the 2723 cm −1 band is the only amorphous band of PP, the orientation of the amorphous phase ( f am ) could be calculated by Equation (2). The transition moment angle at 2723 cm −1 is 90° [ 28 ].…”