Sulfonated melamine

In addition to the two basic groups of antifreeze admixtures, others containing superplastizisers such as sulfonated naphthalene formaldehyde (SNF) and sulfonated melamine formaldehyde (SMF) have been developed. The main advantage afforded by such admixtures is that they produce significant water-reduction. 

Figure 13.3. Absorbed water by concrete with and without sulfonated melamine and formaldehyde condensate superplasticizer vs. immersion time. [Data from Ray I Gupta A P Biswas M, Cement Concrete Composites, 17, No.l, 1995, p.9-21.]...

The flow properties of the slurry may be improved by adding suitable dispersing agents, such as sulforrated rraphthalene formaldehyde condensate (SNFC), sulfonated melamine formaldehyde condensate (SMFC), or lignin-based dispersants. 

Sulfonated naphthalene formaldehyde Sulfonated melamine formaldehyde Poly(vinylphosphoric acid) Poly(styrenephosphoric acid)... 

Precipitated silicas differ from pyrogenic silicas, which are also referred to as aerosils. The most preferred suitable plasticizers are Ugnosulfonate, sulfonated naphthalene-formaldehyde polycondensates, sulfonated melamine-formaldehyde polycondensates, and poly(carboxylate ether)s (16). 

Chemical admixtures in small amounts are added to concrete to enhance the physical, mechanical, chemical, and durability characteristics of concrete. Superplasticizers are admixtures that have the ability to increase the workability of concrete (for easy placement), but also produce high strength concretes. The relative rates of hydration of cement containing superplasticizers at different temperatures are conveniently followed by conduction calorimetry. In Fig. 11 both the rates of hydration and the cumulative amounts of heat developed in cement pastes hydrated at temperatures of20,40, and 55" C are plotted as a function of time. In the figure, SMF refers to the superplasticizer based on sulfonated melamine formaldehyde. The addition of the superplasticizer retards the hydration of cement. The retardation increases with the dosage of the superplasticizer. Also, the retardation effect becomes less significant as the temperature of hydration is increased. 

Chemical admixtures They are generally water-soluble, added mainly to control setting and early hardening of fiesh concrete, and to reduce water requirements. Chemical admixtures include accelerators, normal water reducers, superplasticizers, and retarders. The accelerators may contain calcium chloride, alkali hydroxide, calcium formate, calcium nitrate, etc. Examples of retarders are Na, Ca, or NH4 salts of lignosulfonic acids, hydroxy carboxylicacids,orderivativesofcarbohydrates.Normal water reducers may contain salts of refined lignosulfonic acids, hydroxycarboxylic acids, hydroxylated polymers, etc. Superplasticizers may contain sulfonated melamine formaldehyde, sulfonated naphthalene formaldehyde, car-boxylated synthetic polymers, etc. 

Figure 20. Conduction calorimetric curves of cement mortars containing Na gluconate and sulfonated melamine formaldehyde (SMF).

Ramachandran, V. S., Lowery, M. S., and Malhotra, V. M., Behavior of ASTM Type V Cement Hydrated in the Presence of Sulfonated Melamine Formaldehyde, Mater. Const., 28 133-138 (1995)... 

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