scholarly journals Orientation Analysis of Polyoxymethylene Films Obtained by Rolling and Successive Biaxial Stretching Process.

1995 ◽  
Vol 51 (2) ◽  
pp. 51-61 ◽  
Author(s):  
Norikazu Miyashita ◽  
Kenji Takasa ◽  
Toshihiko Amano
Keyword(s):  
Orientation Analysis ◽  
Biaxial Stretching ◽  
Stretching Process

Physical properties of biaxially oriented PA6 film for simultaneous stretching and sequential processing

2011 ◽  
Vol 31 (1) ◽  
Author(s):  
Masao Takashige ◽  
Toshitaka Kanai
Keyword(s):  
Impact Strength ◽  
Physical Properties ◽  
Physical Property ◽  
High Impact ◽  
Thermal Shrinkage ◽  
Double Bubble ◽  
Biaxial Stretching ◽  
High Impact Strength ◽  
The Difference ◽  
Stretching Process

Abstract There are two different stretching processes that produce the biaxially oriented film, namely the tenter process and double bubble tubular film process. Furthermore, there are two tenter processes, i.e., the sequential biaxial stretching process and simultaneous biaxial stretching process. There is no report describing the difference among film physical properties of the three different processes. The biaxially oriented polyamide film using the double bubble tubular process has good balanced physical property and high impact strength, thus it is used for proper applications utilizing their advantage properties. In this report, the influence of each biaxial stretching process on film physical properties of polyamide, which has hydrogen bond, was studied in detail. As a result, the tentering process film has anisotropic tensile properties between machine direction (MD) and transverse direction (TD). This result was influenced by a later stretching process, namely TD stretching. On the contrary, the double bubble tubular film has good balanced properties, especially thermal shrinkage and impact strength. Tentering simultaneous stretching film has much larger shrinkage in MD than in TD. The sequential stretching film has larger shrinkage in TD than in MD. The double bubble tubular film has high impact strength, because it corresponds to the balanced molecular orientation.

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

2013 ◽  
Vol 747 ◽  
pp. 611-614 ◽  
Author(s):  
Yoshiyuki Kushizaki ◽  
Masayoshi Tokihisa ◽  
Hideki Tomiyama ◽  
Toshiro Yamada
Keyword(s):  
Constitutive Equation ◽  
Deformation Behavior ◽  
Draw Ratio ◽  
Sequential Analysis ◽  
Machine Direction ◽  
Material Constants ◽  
Biaxial Stretching ◽  
Experimental Deformation ◽  
Stretching Ratio ◽  
Stretching Process

The deformation behavior of Polypropylene (PP) film during successive biaxial stretching process which consists of machine direction (MD) stretching process with a roll drawing and transverse direction (TD) stretching with a tentering was analyzed sequentially by using a finite element method (FEM). In order to analyze it, stress-strain curves of casted PP film and uni-axially oriented PP film in MD were measured and fitted into the constitutive equation that the authors developed previously, respectively, and then, material constants for both films were obtained. Deformation behavior during successive biaxial stretching were calculated by applying the constitutive equation with the material constants of casted PP film for MD stretching and uni-axially oriented PP film in MD for TD stretching, respectively. Analytical conditions were the draw ratio of 5 for MD analysis and the stretching ratio of 9.5 for TD analysis. The authors also experimentally measured the thickness of film during and after MD and TD stretching using a pilot plant under the same conditions as analytical condition. Calculated results were able to express qualitatively the experimental deformation behavior of PP film such as the neck-in phenomena during MD stretching and the change of film thickness during MD and TD stretching.

Development of a biaxial stretching test machine and its applications

2018 ◽  
Vol 38 (6) ◽  
pp. 605-616 ◽  
Author(s):  
Kentaro Egoshi ◽  
Toshitaka Kanai ◽  
Kazuhiro Tamura
Keyword(s):  
Light Scattering ◽  
Evaluation Method ◽  
Three Dimensional ◽  
Crystalline Polymer ◽  
Stress And Strain ◽  
Test Machine ◽  
Biaxial Stretching ◽  
As Stress ◽  
Stretching Process

Abstract The evaluation method for a biaxially oriented film was developed using in-situ measurement during the stretching process. It can obtain basic data such as stress-strain curves, birefringence, light scattering, three dimensional refractive indexes and birefringence distribution. Stress and strain as functions of stretching speed and stretching temperature, as well as the deformation of spherulite of semi-crystalline polymer can be obtained by measuring the birefringence and light scattering during the biaxial stretching process with a small piece of polymer sample. The experimental results show the stress, retardation and three dimensional molecular orientations behavior during the simultaneous biaxial stretching and the sequential biaxial stretching process. Stretchability, thickness uniformity and spherulite size can be obtained simultaneously. In this paper, advantages and details of the newly developed system will be discussed with some experimental data.

In situ simultaneous measurement of stress, retardation, and three-dimensional refractive indexes during biaxial stretching experiments under various preheating times

2018 ◽  
Vol 38 (7) ◽  
pp. 703-713
Author(s):  
Kentaro Egoshi ◽  
Toshitaka Kanai ◽  
Kazuhiro Tamura
Keyword(s):  
Evaluation Method ◽  
Three Dimensional ◽  
Semicrystalline Polymers ◽  
Test Machine ◽  
Biaxial Stretching ◽  
Oriented Film ◽  
Set Up ◽  
Short Time ◽  
Stretching Process

Abstract An evaluation method for the stretchability of a biaxially oriented film during the stretching process was recently developed using an in situ measurement test machine. Stress, retardation, three-dimensional refractive indexes, light-scattering image, and birefringence distribution of films could be obtained in a short time. This stretching test machine was applied to examine the film stretchability of both semicrystalline polymers, such as polypropylene, and noncrystalline polymers, such as polystyrene, under various preheating times. From the measurements, the stress of semicrystalline polymers increased with increasing preheating times before stretching the film. However, the stress of noncrystalline polymers did not increase with increasing preheating times. This means that semicrystalline polymer is required to set up an optimum stretching condition of the preheating time for a satisfactory biaxially oriented film. Furthermore, the birefringence distribution and thickness uniformity of the stretched film were measured simultaneously. It was found that the stretchability of polypropylene and polystyrene films could be evaluated with a small piece of the sample using the biaxial stretching test machine.

scholarly journals Characterizing Biaxially Stretched Polypropylene / Graphene Nanoplatelet Composites

2021 ◽  
Vol 8 ◽  
Author(s):  
B. Mayoral ◽  
G Menary ◽  
P Martin ◽  
G Garrett ◽  
B Millar ◽  
...  
Keyword(s):  
Screw Extruder ◽  
Melt Mixing ◽  
Electrically Conductive ◽  
Conductive Composites ◽  
Biaxial Stretching ◽  
Weight Concentration ◽  
Vacuum Forming ◽  
Twin Screw ◽  
Polymer Crystallinity ◽  
Stretching Process

In this work, polypropylene (PP) nanocomposites containing different weight concentration of graphene nanoplatelets (GNP) were prepared by melt-mixing using an industrial-scale, co-rotating, intermeshing, twin-screw extruder. The materials were then compression moulded into sheets, and biaxially stretched at different stretching ratios (SRs) below the PP melting temperature. The effects of GNP content and biaxial stretching on the bulk properties of unfilled PP and PP/GNP nanocomposites have been investigated in details. Results show that the addition of GNP (>5wt%) can lead to electrically conductive composites due to the formation of percolation network. The GNP have led to increased polymer crystallinity and enhanced materials stiffness and strength. Biaxial stretching process further enhances the materials mechanical properties but has slightly decreased the composites electrical conductivity. The PP/GNP nanocomposites were also processed into 3D demonstrator parts using vacuum forming, and the properties of which were comparable with biaxially stretched composites.

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