Accession Number:

ADA279017

Title:

Cement Paste Matrix Composite Materials Center

Descriptive Note:

Final rept. 1 Apr 1992-30 Sep 1993

Corporate Author:

ILLINOIS UNIV AT URBANA DEPT OF CIVIL ENGINEERING

Personal Author(s):

Report Date:

1993-11-30

Pagination or Media Count:

25.0

Abstract:

Investigations of the development of the microstructure of MDF macro-defect-free cement during processing, showed progressive changes in the properties of the polyvinyl alcohol matrix. Excessive processing times lead to the introduction of macro-defects, caused by failure of either interphase or polymer matrix. Macro-defects are proceeded by the formation of small tears or voids which coalesce and enlarge. Further studies on the interdiffusion of polymer interfaces has provided the first experimental evidence of the polymer reptation theory. Interfaces develop fractal character and will influence the fracture of polymer welds and confined polymer fluids. NMR spectroscopy studies on hydration of cementitious compounds have been extended to calcium silicates, using 170 for the first time. Calcium x-ray adsorption spectroscopy has also been used in an exploratory study. The formation of an reaction intermediate with five coordinated silicon was observed. The conditions of synthesis of intercalated PVA organoceramic complex have been explored. The results suggest that this complex cannot form in MDF cements. An organotitanium complex that improves the water resistance of MDF cement has been shown to form a 3- dimensional PVA gel which is dehydrated to form a water impervious film. The role of PVA cross-linking in controlling processing and properties is discussed.

Subject Categories:

  • Polymer Chemistry
  • Ceramics, Refractories and Glass
  • Laminates and Composite Materials
  • Mechanics

Distribution Statement:

APPROVED FOR PUBLIC RELEASE