Water-absorptivity and mechanical behaviors of PTFE/PA6 and PTFE/PA66 blends

• Published in: Transactions of Nonferrous Metals Society of China Vol. 16; no. B02; pp. 498 - 503
• Main Author: 赵荣国 罗文波 肖华明 吴国忠
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.06.2006
• Subjects: complex viscosity; PTFE/PA6 blends; PTFE/PA66 blends; PTFE/PA66混合物; PTFE/PA6混合物; strength; water absorptivity; 力学性质; 吸水性; 聚四氟乙烯/聚酰胺混合物; PTFE/PA6 blends; PTFE/PA66 blends; water absorptivity; strength; complex viscosity
• ISSN: 1003-6326
• DOI: 10.1016/S1003-6326(06)60243-4

The effects of polytetrafluoroethylene （PTFE） content on water-absorptivity, tensile strength, flexural strength, and notched impact strength of polytetrafluoroethylene/polyamide 6 （PTFE/PA6） and polytetrafluoroethylene/polyamide 66 （PTFE/PA66） blends were investigated by water immersion test, uniaxial tensile test, three-point test, and Charpy impact fracture test. The water-absorptivity in the blend decreases with increasing PTFE content, which indicates that the PTFE phase restrains the polyamide phase from water absorption. For water-free blends, the addition of PTFE causes a reduction in tensile strength, while for water-absorbed PTFE/PA6 blends, the tensile strength increases with increasing PTFE. Simultaneously, the absorbed water improves the elongation, but results in a notable reduction in flexural strength of the blends. Although the addition of PTFE causes a reduction in notched impact strength of the blends, as compared to pure polyamide, the absorbed water has little effects on the notched impact strength of the blends. Finally, the effects of temperature and loading frequency on complex viscosity parameters of PTFE/PA6 and PTFE/PA66 melts were tested. It is found that the complex viscosity of PTFE/PA6 melt is reversed with increasing temperature and shear velocity, but that of PTFE/PA66 melt increases approximately in exponential form with increasing temperature. To fill polyamide with suitable mass percentage of PTFE can effectively reduce the viscosity of blend, and as a result, the molding and processing properties are improved.