Isocyanate-treated cellulose pulp and its effect on the alkali resistance and performance of fiber cement composites

Author(s)

Denzin Tonoli, Gustavo Henrique ^[1] ; Mendes, Rafael F. ^[1] ; Siqueira, Gilberto ^[2] ; Bras, Julien ^[2] ; Belgacem, Mohamed N. ^[2] ; Savastano, Jr., Holmer ^[3]

Affiliation

^[1] Univ Fed Lavras, Forestry Sci Dept, BR-37200000 Lavras, MG - Brazil

^[2] Grenoble INP Pagora, Lab Genie Proc Papetiers LGP2, UMR CNRS 5518, F-38402 St Martin Dheres - France

^[3] Univ Sao Paulo, Dept Food Engn, Fac Zootecnia & Engn Alimentos, BR-13635900 Pirassununga, SP - Brazil

• Document type: Journal article
• Source: HOLZFORSCHUNG; v. 67, n. 8, p. 853-861, DEC 2013.
• Web of Science Citations: 14

Abstract

The impact of grafted surface of cellulose fibers on the mechanical and physical properties of fiber-cement composites (FCC) has been investigated. The grafting was performed with n-octadecyl isocyanate {[}i.e., with an aliphatic isocyanate (AI)], with the intention to protect the cellulose fiber from alkali degradation in the cement matrix. The chemical changes, observed by contact angle measurements and X-ray photoelectron spectroscopy, showed a higher hydrophobic character of AI-treated fibers. The strength of FCC was tested during 28 days of curing treatment. The extracted AI-treated fibers contributed to higher specific energy and final specific deflection after accelerated aging cycles in comparison with the reference composites reinforced with untreated fibers. The higher values of limit of proportionality and modulus of elasticity for composites with AI-treated fibers are an evidence of the densification of the fiber-matrix transition zone. The modulus of rupture values were higher for composites with AI-treated and Soxhlet-extracted fibers after 200 soak and dry aging cycles. In comparison with the reference, AI-treated fibers decreased the water absorption and the apparent porosity of the FCC. The modification of fibers could be a new strategy to improve the performance and stability of cement products reinforced with natural fibers. (AU)

• FAPESP's process: 09/10614-0 - Fundamental mechanical characteristics of non-conventional composites reinforced with cellulose and synthetic fibres: contribution to sustainable building materials
• Grantee: Holmer Savastano Junior
• Support Opportunities: Regular Research Grants