Mortars organic additives

Table 6.1 Organic additives in mortars and their classification by their effects on fresh and hardened mortars. Some of the protein additives are matched into more, sometimes even contradicting, categories, due to their different influence on fresh and moderately hardened mortars [22,24]...

A great part of the organic additives contains various amounts of proteinaceous materials. The identification of proteinaceous binder could help to explain the unusual properties of the mortars, such as high firmness, hydrophobicity of surfaces, and, for frescoes, high stability [24]. 

The decrease of peak numbers was observed, when the spectra of the same amounts of fresh (12 weeks old) and aged (9 months old) mortars were compared. This decrease might be caused by activity of ubiquitous microorganisms that live on the mortar surfaces in biofilms. Especially in mild climate conditions, algae and cyanobacteria [35] can appear here moulds (Aspergillus, Penicillium, Fusarium, Mucor) [36] and bacteria (Arthrobacter Bacillus, Micrococcus, Staphylococcus) [37,38] have been discovered as well. The microorganisms secrete various hydrolytic enzymes that can decompose the organic additives, namely proteins, and make their sample identification less sensitive... 

Fighting in Italy was as bitter and the enemy defenses as stubborn as any experienced by American forces in World War II. The mountainous Italian terrain, with its abundance of defiladed positions inaccessible to artillery fire, placed a heavy demand on high trajectory weapons, particularly the 4.2-inch mortar. In addition, 4.2-inch mortar units were indispensable to Ranger and Commando units which lacked organic heavy weapons. Most infantry commanders were at first unaware of the potential of the 4.2-inch mortar, but once they had seen the weapon in action they were usually anxious for mortar support. In Italy the chemical mortar truly came of age. 

Cinnamic acid (0.01 mol), metal nitrate (0.015 mol) and a few drops of nitric acid were taken in a mortar and ground for about 1-2 h. After completion, as ascertained by TLC, the reaction mixture was treated with 2% sodium carbonate solution, followed by the addition of dichloromethane or dichloroethane. The organic layer was separated, dried over Na2S04 and evaporated under vacuum,... 

Polymer-modified cement mixes are produced by mixing together an inorganic cement (most commordy Portland cement), water, and a dispersion of an organic polymer. If concrete aggregate or sand is also added, polymer-modified concrete or mortar mixes are obtained. Compared with similar polymer-free mixes, the addition of water may be reduced or omitted entirely, as the polymeric dispersion supphes part or all of the water needed for hydration and for obtaining adequate rheology of the mix. 

Some but not all organic reactions proceed well in the absence of solvent(s). Develop a solvent-free protocol for the aldol reaction using solid sodium or potassium hydroxide as the base. The reaction can be successfully performed on a 5-10 mmol scale, using an equivalent of base. Bear in mind that the base should be finely divided, so it should first be crushed with a mortar and pestle. In addition, the condensation partners should be mixed thoroughly before the base is added. The reaction should take no more than 20-25 minutes, and the mixture should be acidified to pH 5 with 10% HCI prior to isolation of the product. Characterize the product by its melting point and using spectroscopic techniques. 

---