PMMA - Impregnated Silica Gels: Synthesis and Characterization

Abstract

Shaped microporous silica has been prepared by a sol-gel process. The resulting silicas have 50% open porosity. The open porosity is filled by immersing the shapes in methyl methacrylate (MMA) and polymerizing with ultraviolet radiation. The fully impregnated silica is recovered in net shape. The outstanding feature of the PMMA-impregnated silica is its transparency. There is little loss from scattering because of the nanometer scale of the microstructure and the similarity in index of refraction for silica and PMMA. The flexure strength of the silica-PMMA composite has been measured in 4-point bending. The strength increases at slower strain rates because the PMMA provides crack blunting. The composites can withstand thermal shocks up to about 150 deg C without losing strength. The thermal expansion coefficient for the range 0 to 150 deg C follows a mixing rule for 50% silica - 50% PMMA. While the mechanical behavior of the composite largely follows that of bulk PMMA, the microhardness is 3 to 5 times greater than for bulk PMMA. Keywords: PMMA, Polymethyl methacrylate, Impregnated silica gels, Sol-gel process, Optical materials, Organicydes, Polymers.

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Document Details

Document Type
Technical Report
Publication Date
Jun 20, 1990
Accession Number
ADA223639

Entities

People

  • Bennet Abramoff
  • Lisa C. Klein

Organizations

  • Rutgers University–New Brunswick

Tags

Communities of Interest

  • Weapons Technologies

DTIC Thesaurus Topics

  • Composite Materials
  • Materials
  • Materials Testing
  • Mechanical Properties
  • Military Research
  • New Jersey
  • Optical Materials
  • Optical Properties
  • Optics
  • Polymers
  • Polymethyl Methacrylate
  • Radiation
  • Refractive Index
  • Silica Gels
  • Sol Gel Processes
  • Strain Rate
  • Thermal Shock

Readers

  • Nanocomposite Materials Science
  • Polymer Science and Technology
  • Reinforced Composite Materials