Effect of layered silicates and reactive compatibilization on structure and properties of melt-drawn HDPE/PA6 microfibrillar composites

• Published in: Polymer bulletin (Berlin, Germany) Germany), 2016-06, Vol.73 (6), p.1673-1688
• Main Authors: Kelnar, Ivan, Kaprálková, Ludmila, Kratochvíl, Jaroslav, Padovec, Zdeněk, Růžička, Milan, Hromádková, Jiřina
• Format: Article
• Language: English
• Subjects: Blending; Characterization and Evaluation of Materials; Chemistry; Chemistry and Materials Science; Clay; Complex Fluids and Microfluidics; Composite materials; Copolymers; Draw ratio; Finite element method; High density polyethylenes; Impact strength; Injection molding; Mechanical properties; Nanocomposites; Organic Chemistry; Original Paper; Particle size; Physical Chemistry; Polymer blends; Polymer Sciences; Scanning electron microscopy; Silicates; Soft and Granular Matter; Temperature
• ISSN: 0170-0839; 1436-2449
• DOI: 10.1007/s00289-015-1570-6

Microfibrillar composites (MFCs) of HDPE matrix with PA6 reinforcing fibrils formed in situ by melt drawing were modified by ethylene/glycidyl methacrylate copolymer (PEGMA) and addition of layered silicates using different mixing protocols. The goal was enhancement of adhesion between fibrils and matrix, their reinforcement by clay, and evaluation of the effect of clay on the MFC morphology, especially the fibril dimensions. Improved mechanical properties, including toughness, were found in the case of pre-blending Cloisite 15A (C15) with both polymeric components. Pre-blending of Cloisite C30B (C30) in PA6 is effective at low draw ratios only, whereas simultaneous addition of both clays leads to significant worsening of properties. In many cases, low stiffness increase indicates existence of clay-induced controversial effects which may eliminate reinforcement induced by fibrils and clay. The results indicate that these effects are significantly affected by the extent and course of clay migration between polymer phases during extrusion-mixing and melt drawing. Possible explanation of affecting the properties due to low-modulus interface supported by finite element analysis (FEA) is presented.