On-Line Birefringence Measurement in Film Blowing of a Linear Low Density Polyethylene
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A. Ghaneh-Fard
Abstract
Blown film properties depend on the thermo-mechanical history experienced by molten polymer during biaxial deformation. In this study on-line birefringence measurements along the length of the bubble in film blowing of a linear low density polyethylene (LLDPE) were carried out in order to assess the stress level in the melt zone and total orientation in the solid zone. Bubble temperature measurements were carried out to find out the onset and the end of crystallization. Strain rates were also determined from bubble diameter and axial velocity measurements. We have focused on the effects of key processing parameters on the thermo-mechanical history of polymers. The relations between the birefringence and temperature profiles are described. The birefringence value is shown to be very small in the molten zone and increases rapidly as crystallization proceeds. The birefringence of the solidified film is strongly dominated by the crystalline phase contribution. Stresses in the molten blown film were calculated using the data of birefringence and pressure inside the bubble. The birefringence technique appears to be a promising but limited tool to determine stresses occurring in film blowing.
© 1997, Carl Hanser Verlag, Munich
Artikel in diesem Heft
- Contents
- Contents
- Editorial
- Third in a Series: Pioneers of Polymer Processing: Charles Goodyear
- Screw Extrusion/Mixing
- Chaotic Features of Flow in Polymer Processing Equipment-Relevance to Distributive Mixing
- Influence of Design on Mixing Efficiency in a Variable Intermeshing Clearance Mixer
- Simulation of Non-Isothermal Flow in a Modular Buss Kneader and Comparison with Experiment
- Rheological Behaviour of LLDPE/LDPE Blends under Elongational Deformation
- Effect of Compounding Conditions on Mechanical Properties of Glass Fiber-Reinforced Polyamide-6
- Die Extrusion
- A New Approach to Simulation of Die Flow which Incorporates the Extruder and Rotating Screw Tips in the Analysis
- New Aspects Concerning the Design of Coathanger Dies
- Film
- On-Line Birefringence Measurement in Film Blowing of a Linear Low Density Polyethylene
- Brittle Melt Rupture Phenomena in Polymer Processing
- Moulding
- Injection Molding of LDPE/BaSO4 Blends
- An Experimental Study of Rotational Molding of Polypropylene/Polyethylene Copolymers
- Determination of the Inter-Relationships Between Processing Conditions and Properties of an Injection Molded Silicone Ring Using an Experimental Design
- Numerical Simulation of the Flow and Fiber Orientation in Reinforced Thermoplastic Injection Molded Products
- Wide-Angle X-Ray, Densitometric and Microscopical Studies on Injection Molded Polypropylene Disks
Artikel in diesem Heft
- Contents
- Contents
- Editorial
- Third in a Series: Pioneers of Polymer Processing: Charles Goodyear
- Screw Extrusion/Mixing
- Chaotic Features of Flow in Polymer Processing Equipment-Relevance to Distributive Mixing
- Influence of Design on Mixing Efficiency in a Variable Intermeshing Clearance Mixer
- Simulation of Non-Isothermal Flow in a Modular Buss Kneader and Comparison with Experiment
- Rheological Behaviour of LLDPE/LDPE Blends under Elongational Deformation
- Effect of Compounding Conditions on Mechanical Properties of Glass Fiber-Reinforced Polyamide-6
- Die Extrusion
- A New Approach to Simulation of Die Flow which Incorporates the Extruder and Rotating Screw Tips in the Analysis
- New Aspects Concerning the Design of Coathanger Dies
- Film
- On-Line Birefringence Measurement in Film Blowing of a Linear Low Density Polyethylene
- Brittle Melt Rupture Phenomena in Polymer Processing
- Moulding
- Injection Molding of LDPE/BaSO4 Blends
- An Experimental Study of Rotational Molding of Polypropylene/Polyethylene Copolymers
- Determination of the Inter-Relationships Between Processing Conditions and Properties of an Injection Molded Silicone Ring Using an Experimental Design
- Numerical Simulation of the Flow and Fiber Orientation in Reinforced Thermoplastic Injection Molded Products
- Wide-Angle X-Ray, Densitometric and Microscopical Studies on Injection Molded Polypropylene Disks