Study on the Formation of β-Crystalline from Isotactic Polypropylene Fiber
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X. Chen
Abstract
In this paper the conditions for the manufacture of high content β-form crystal isotactic polypropylene fiber in the presence of β nucleation and the β to α form transition during processing were studied. The results showed that the melt temperature had little effect on the relative content of β-form (K value) presented in as-spun fibers within a certain temperature range (210 to 230°C) while the cooling rate and cooling medium had a significant effect on it. In the case of a constant pump deliver (Q), the K value in the as-spun fiber decreased from 0.95 to 0 as the spinning speed increased from 3.25 m/min to 70 m/min. The smaller the thermal conductivity of cooling medium, the greater was the K value. After stretching the β-form PP fiber, there were many crevices at the fiber surface. It was confirmed by the mercury porosimetry that the drawn fiber possessed microvoid structure. The size and quantity of microvoids were closely related to the K value, stretching temperature and stretching ratio. Compared with PP fiber without nucleating agent, the drawn fiber had a lower apparent density and its moisture absorption was improved.
© 1991, Carl Hanser Verlag, Munich
Artikel in diesem Heft
- Contents
- Contents
- Review Paper
- Existing Scale-up Rules for Single-screw Plasticating Extruders
- Internal Mixers
- Scale-up Effect in Internal Mixers
- Mixing and Extrusion of High Silica and all Silica-natural Rubber Compounds
- Screw Extrusion
- An Analytical Model of Partial and Thorough Melting in Single-screw Extruders
- Dimensionless Non-Newtonian Isothermal Simulation and Scale-up Considerations for Modular Intermeshing Corotating Twin Screw Extruders
- Erratum
- Die Extrusion
- Extrusion of Rubber Compounds and Highly Filled Thermoplastics through Coathanger Dies
- Pressure Oscillations during Capillary Extrusion of High Density Polyethylene
- Frequency Analysis of Pressure Fluctuations in a Single Screw Extruder
- Fibers and Films
- Orientation and Mechanical Property Development in the Melt Spinning of Fibers from Polyetherimide and Polyarylate
- Study on the Formation of β-Crystalline from Isotactic Polypropylene Fiber
- Biaxially-oriented Polyethylene Films by Compression of Injected Moldings
- Modelling of the Cooling of Semi-crystalline Polymers during their Processing
- Molding
- Non-isothermal Mold Filling and Curing Simulation in Thin Cavities with Preplaced Fiber Mats
- Predicting the Skin-Core Boundary Location in Injection Moldings
Artikel in diesem Heft
- Contents
- Contents
- Review Paper
- Existing Scale-up Rules for Single-screw Plasticating Extruders
- Internal Mixers
- Scale-up Effect in Internal Mixers
- Mixing and Extrusion of High Silica and all Silica-natural Rubber Compounds
- Screw Extrusion
- An Analytical Model of Partial and Thorough Melting in Single-screw Extruders
- Dimensionless Non-Newtonian Isothermal Simulation and Scale-up Considerations for Modular Intermeshing Corotating Twin Screw Extruders
- Erratum
- Die Extrusion
- Extrusion of Rubber Compounds and Highly Filled Thermoplastics through Coathanger Dies
- Pressure Oscillations during Capillary Extrusion of High Density Polyethylene
- Frequency Analysis of Pressure Fluctuations in a Single Screw Extruder
- Fibers and Films
- Orientation and Mechanical Property Development in the Melt Spinning of Fibers from Polyetherimide and Polyarylate
- Study on the Formation of β-Crystalline from Isotactic Polypropylene Fiber
- Biaxially-oriented Polyethylene Films by Compression of Injected Moldings
- Modelling of the Cooling of Semi-crystalline Polymers during their Processing
- Molding
- Non-isothermal Mold Filling and Curing Simulation in Thin Cavities with Preplaced Fiber Mats
- Predicting the Skin-Core Boundary Location in Injection Moldings
