Effects of preferential encapsulation of glass fiber on the properties of ternary GF/PA/PP blends

• Published in: Polymer composites Vol. 21; no. 1; pp. 41 - 50
• Main Authors: Maeng, Yoo Jae, Yoon, Byung Seon, Suh, Moon Ho, Lee, Suck Hyun, Im, Wan Bin
• Format: Journal Article
• Language: English
• Published: Hoboken Wiley Subscription Services, Inc., A Wiley Company 01.02.2000; Willey; Blackwell Publishing Ltd
• Subjects: Applied sciences; Composites; Exact sciences and technology; Forms of application and semi-finished materials; Polymer industry, paints, wood; Technology of polymers; Encapsulation; Scanning electron microscopy; Nylon; Polymer blends; Thermoplastics; Stress strain relation; Propylene polymer; Fiber reinforced material; Mechanical properties; Composite material; Impregnation; Shear viscosity; Impact strength; Injection molding; Fibre reinforced plastics; Glass fiber; Rupture strength; Strength; Rheological properties
• ISSN: 0272-8397; 1548-0569
• DOI: 10.1002/pc.10163

Long fiber molding materials are expected to play an important role in the near future. This paper describes a series of experiments performed to examine properties of ternary blends containing glass fiber (GF), polyamide (PA), and polypropylene (PP). The continuous glass fiber was impregnated with one of the blend constituent polymers by our specially designed impregnation apparatus and cut into chips of 6 mm length. These chips and the other polymer were used to produce various testing specimens in a twin screw extruder or in injection molding machine. The results indicated that the effect of fiber addition on the mechanical and rheological properties is clearly dependent on the order of impregnation process. In the blends containing the GF/PA + PP, the GFs are preferentially encapsulated with PA, and therefore the mechanical properties are superior to the blends with the GF/PP + PA in which the PP phase is located surrounding the GFs. This improved wetting of fibers by sequential impregnation not only resulted in better properties but also protected the fibers from shear action of the screw, thereby allowing significant increase in average fiber length to be achieved in the injection molding process.