High Performance Polyamide 6 Fibers Using Polycarbonate Based Thermoplastic Polyurethane Thin Film Coatings- a Novel Method

Abstract

Polycarbonate based thermoplastic polyurethanes (CPU2) were prepared and coated onto polyamide 6 (PA 6) fibers. The CPU2 thin film coatings were prepared by dipping the PA 6 fibers into a viscous CPU2 adduct and cured at 100 C for 12 h. Both the tensile strength and the elongation at break of the CPU2 thin film coated PA 6 fibers (CPU2-PA6) increased although both the magnitudes of CPU2 are much lower than for the original PA 6 fibers. FE-SEM observation revealed that there existed an interface interaction region of 10 mm at the interface of PA 6 fiber and the CPU2 thin film coating. Generally speaking, it is considered that the break of PA 6 fibers is due to the formation of the micro-cracks on the fiber surface when it is under a tensile load. The coating of CPU2 onto the PA 6 fibers reduced the formation of micro-cracks during the elongation process, resulted in the improvement of the mechanical properties. Also, the CPU2-PA6 fibers when exposed to weathering tests to check the weathering resistance, showed an increase in the tensile strength for 0-50 h of exposure. This was due to the UV light induced crystalline transformation, i.e., from the crystalline phase to the crystalline phase. The CPU2-PA6 fibers almost retained the strength even after 200 h of exposure in a weatherometer. The crystalline transformations due to the UV irradiations have not been reported yet. Also, the CPU2 showed good adhesion property with the PA 6 films. The blending with various polymers or composites is generally employed for the performance enhancement of PA 6 fibers. On the contrary, the method employed in this study improved the performance of PA 6 fibers without changing its inherent morphological properties.KEY WORDS: Polyamide 6 Fiber / Polyurethane Thin Film / Coating / Micro-cracks / Interface Interaction / Plastic-type Break / Metallic-type Break / Weathering Tests / Polyamide fibers (PAs) are used for a wide variety of applications. They include the textile industry, engineering applications, biomedical and marine applications. The properties of PAs are the high melting point, good mechanical strength, good resistance to hydrocarbons, and the ease of fabrication and processing.1-3 However, the polyamide 6 (PA 6) fibers are prone to break under the mechanical stress due to the formation of micro-cracks on the surface. While, the polyurethanes are widely used in the coatings, adhesives, sealants, foams, elastomers and so on. Thermoplastic polyurethane elastomers are well known for their abrasion resistance, flexibility and high cohesive strength. [4][5][6] They are synthesized from the polymer glycol, diisocyanate and a chain extender. The final structure of polyurethane consists of a soft segment formed from the polymer glycol and a hard segment from the diisocyanate and the chain extender. The soft segment can be classified as an ether or ester series, including the carbonate ones. 7,8 Studies have been reported with polyamide in the thermoplastic elastomers or rubbers as blends. 9 The PA 6/acrylonitrile-butadiene-sty...

Data on Specific Polymers

“…240 Polyamide-6 fibers were coated with polycarbonate-based thermoplastic polyurethane. 241 Polyamide-6 fibers without coating break because cracks are formed on weathering. 241 The coating forms a 10 m layer on the fiber surface which protects polyamide-6.…”

“…241 Polyamide-6 fibers without coating break because cracks are formed on weathering. 241 The coating forms a 10 m layer on the fiber surface which protects polyamide-6. 241 Figure 14.51 illustrates performance of coated and uncoated fibers during tensile testing.…”

“…241 The coating forms a 10 m layer on the fiber surface which protects polyamide-6. 241 Figure 14.51 illustrates performance of coated and uncoated fibers during tensile testing. 241 Dimer fatty acid-based polyamides are produced from renewable resources to replace petroleum-based materials.…”

“…241 Figure 14.51 illustrates performance of coated and uncoated fibers during tensile testing. 241 Dimer fatty acid-based polyamides are produced from renewable resources to replace petroleum-based materials. 242 On exposure to fluorescent lamp/condensation device, the formation of peroxides was found to be very rapid and accompanied by high gel fraction formation and chain breaking.…”

Structure and mechanical behaviors of thermoplastic polyurethane thin film coated polyamide 6 fibers part II. A solution coating method

“…In our previous study, it was found that polycarbonatebased thermoplastic polyurethane (TPU) thin film coatings based on a reactive bulk coating method, improved the mechanical properties of the PA6 fibers and that the interfacial interaction between the thin film coating and PA6 fiber played a significant role in the improvement of mechanical property [16][17][18][19]. But the fast curing of polycarbonate-based TPU caused difficulty during dip coating in the reactive PU adduct, which cause difficulties for certain applications on the industrial scale.…”