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

• Published in: Journal of applied polymer science Vol. 93; no. 4; pp. 1951 - 1956
• Main Authors: Baltá Calleja, F. J., Flores, A., Michler, G. H.
• Format: Journal Article
• Language: English
• Published: Hoboken Wiley Subscription Services, Inc., A Wiley Company 15.08.2004; Wiley
• Subjects: amorphous polymers; Applied sciences; entanglements; Exact sciences and technology; glass transition temperature; microindentation hardness; molecular weight; Physicochemistry of polymers; Polymer industry, paints, wood; Technology of polymers; Viscoelasticity; Elastic modulus; SAN; Annealing; Methyl methacrylate polymer; molecular weight; entanglements; Hardness; Methyl methacrylate copolymer; glass transition temperature; microindentation hardness; Acrylonitrile polymer; Glassy polymer; amorphous polymers; Amorphous polymer; Styrene polymer
• ISSN: 0021-8995; 1097-4628
• DOI: 10.1002/app.20665

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