Microindentation studies at the near surface of glassy polymers: Influence of molecular weight

✍ Scribed by F. J. Baltá Calleja; A. Flores; G. H. Michler

• Publisher: John Wiley and Sons
• Year: 2004
• Tongue: English
• Weight: 98 KB
• Volume: 93
• Category: Article
• ISSN: 0021-8995
• DOI: 10.1002/app.20665

✦ Synopsis

Abstract

The viscoelastic‐plastic properties of various amorphous, glassy polymers [polystyrene (PS), poly(styrene‐acrylonitrile) copolymer (SAN), poly(methyl methacrylate) (PMMA), poly(vinyl chloride) (PVC), polycarbonate (PC)] in the micron and submicron range were investigated by means of load‐displacement analysis from depth‐sensing experiments. Hardness and Young's modulus values decrease rapidly with increasing depth up to a few microns. New data on the glass transition temperature correlation with microhardness are presented. The influence of annealing below the glass transition temperature upon the microhardness for various glassy polymers is pointed out. For PS, the influence of the molecular weight variation and molecular weight distribution on the microhardness is reported. Results are discussed on the basis of an entanglement network model, recently developed to explain the fine structure of crazes in amorphous polymers. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 1951–1956, 2004