Priya, Viswanath; Dr. Eby Thomas, Thachil(Cochin University of Science and Technology, September , 2007)
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Abstract:
Research in the field of polymer modified cement has been carried out for
the last 70 years or more. Polymers are mostly used to enhance durability and
sustainability of cement concrete and in combination with classical construction
materials a synergistic effect is obtained. In this work different polymers were
added to Portland cement in various proportions and the mechanical and
chemical resistance properties of the resultant composites when exposed to
chemical environments were studied. Microstructural studies were also carried
out to investigate the morphology of the composite and analyse the nature of
interactions taking place between the cement and polymer phases. Though most
polymers did not improve the compressive strength of the cement paste, it was
found that they enhanced the resistance of the virgin cement paste to external
chemical environments. The polymers seal the pores in the cement matrix and
bridge the microcracks within the composite. Some of the polymers underwent
chemical interactions with the cement paste thereby interfering in the hydration
of cement. Polymers also decreased the leachability of water soluble components
of virgin cement resulting in composites having improved durability. An attempt
to correlate the structure of the polymers with the properties of the resultant
composites is also presented.
Description:
Department of
Polymer Science and Rubber Technology, Cochin University of
Science and Technology
Mary Lubi, C; Dr. Eby Thomas, Thachil(Cochin University of Science & Technology, January , 2007)
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Abstract:
This research project aims at developing new applications for CNSL in the
polymer field. Cashew nut shell liquid (CNSL) is a cheap agro-byproduct and
renewable resource which consists mainly of substituted phenols. By using CNSL
in place of phenol, phenol derived from petrochemicals can be conserved and a
cheap agro-byproduct utilized.In this study CNSL based resin is prepared by condensing a mixture of
phenol and CNSL with hexamethylenetetramine and the effect of P: F ratio and
CNSL: P ratio on the properties of synthesized resin is studied. The adhesive
properties of CNSL based resin in combination with neoprene rubber are
investigated. The effect of varying the stoichiometric ratios between total phenol
and formaldehyde and CNSL and phenol of the resin, resin content, choice and
extent of fillers and adhesion promoters in the adhesive formulation are studied.
The effect of resin on the ageing properties of various elastomers is also studied by
following changes in tensile strength, elongation at break, modulus, tear strength,
swelling index and acetone soluble matter. Crude CNSL and resins with different
P: F ratios and CNSL: P ratios are incorporated into elastomers. Lastly, utility of
CNSL based resin as binder for making particleboard is investigated.The results show that CNSL based resin is an effective ingredient in
adhesives for bonding aluminium to aluminium. The resin used for adhesive
fonnulation gives the best performance at 45 to 55 phr resin and a total phenol:
formaldehyde of l:2.9. The resin when added at a rate of l5 phr improves ageing
characteristics of elastomers with respect to mechanical properties. The reaction
mixture of CNSL and hexa and the resin resulting from the condensation of CN SL,
phenol and hexa can be used as effective binders for moulding particleboard.
Description:
Department of Polymer
Science and Rubber Technology, Cochin University of Science and
Technology