Soil conditioners, synthetic

Soil conditioners are materials that measurably improve the physical characteristics of the soil as a plant growth medium. Typical uses include erosion control, prevention of surface sealing, and improvement of water infiltration and drainage. Many natural materials such as peat and gypsum are used alone or in combination with synthetics for soil conditioning. This article is concerned with synthetic soil conditioners, many of which are introduced as polymeric systems similar to the gels and foams formed in situ by chemical grouts. 

The largest user of phenol in the form of thermosetting resins is the plastics industry. Phenol is also used as a solvent and in the manufacture of intermediates for pesticides, pharmaceuticals, and dyestuffs. Styrene is used in the manufacture of synthetic rubber and polystyrene resins. Phthalic anhydride is used in the manufacture of DMT, alkyd resins, and plasticizers such as phthalates. Maleic anhydride is used in the manufacture of polyesters and, to some extent, for alkyd resins. Minor uses include the manufacture of malathion and soil conditioners. Nitrobenzene is used in the manufacture of aniline, benzidine, and dyestuffs and as a solvent in polishes. Aniline is used in the manufacture of dyes, including azo dyes, and rubber chemicals such as vulcanization accelerators and antioxidants. 

Applications as soil conditioners (2) and in the dewatering of phosphate slimes (3) were among the first successful uses of synthetic polymeric flocculants. For this reason, several test methods based on permeability have been developed, including the re-filtration rate method of La Mer (3). 

Acrylamide with a demand of 200,000 tons year" is one of the most important commodities in the world. It is used for the preparation of coagulators, soil conditioners, stock additives for paper treatment, and in leather and textile industry as a component of synthetic fibers. Conventional chemical synthesis involving hydration of acrylonitrile with the use of copper salts as a catalyst has some disadvantages rate of acrylic acid formation higher than acrylamide, by-products formation and polymerization, and high-energy inputs. To overcome these limits since 1985, the Japanese company Nitto Chemical Industry developed a biocatalyzed process to synthesize... 

February 29th) into the calendar to make it match the. solar year. Most work on intercalation compounds has been on synthetic systems in which atoms, ions, or molecules have been inserted between layers of the host material. However, some aluminosilicates that we have encountered above provide useful examples. Thus talc and micas form layered structures with ions between the silicate sheets (Fig. 16.3). Some minerals, including all clays, have water molecules intercalcatcd between the framework sheets. In some, such as vermiculile, the water may rapidly and dramatically be evacuated by heating. The water molecules leave faster than they can ditfuse along the layers—exfoliation occurs. The result is the familiar expanded vermiculile used as a packing material and as a potting soil conditioner. 

Many other zeolites than the natural are synthesized. Synthesis of zeolite is made under the hydro thermal condition from room temperature to 673 K. The phase of crystallization varies with sort of raw material, ratio of constituent of raw material, mold material and synthetic condition. These synthetic zeolites are used for ion exchanger, molecular sieve, industrial catalyst and carrier of catalyst, builder for detergent and soil conditioner, etc. 

Starch phosphate was combined with rosin and alum to increase the dry strength and ink retention characteristics of paper.1677 Starch phosphates have also been used as soil conditioners to increase water retention.1678 Starch phosphates improved the dispersion and dye reception of synthetic fibers,1667 and are used to stabilize water,1543 finger paints,1679 and white coating colors.1680 Phosphonoamidated starches are useful in paper sizing.1681 Biodegradable films were produced by combining starch phosphate with poly (vinyl alcohol).1682 Phosphonoacetyl starch added to polyacrylonitrile improved it affinity for dyes.1683... 

The bringing about of a satisfactory state of aggregation in many soils, and the maintenance of this state, present many problems. Often almost the only practical method for doing this is to use a rotation that provides for the periodic use of sod crops. On high-priced land, and where the area available is limited, this is often an expensive practice. It is these facts that lead to the development of synthetic soil conditioners that can act as aggregate stabilizers but are not decomposed rapidly, if at all, by microorganisms (Quastel, 1954 Harris et al., 1966). 

Synthetic soil conditioners do not form aggregates but they are strong stabilizers of those that are already naturally present in the soil, or formed mechanically. This is one outstanding case where there is a sharp line of distinction between formation and stabilization of aggregates. The synthetic polymers combine with soil particles very quickly in... 

The sponsors of synthetic soil conditioners initially had high hopes that they would be of great value in agriculture. This did not prove to be the case for various reasons, chiefly cost of materials, lack of aggregate forming ability, difficulty of application, and disappearance of most of the benefits after one season. 

Soil conditioners vary in both their origin and composition. Soil conditioners can be synthetic or naturally occurring organic or inorganic. 

There are three major classes of synthetic polymeric materials used as soil conditioners to improve agricultural production ... 

WH. Gardner, Use of synthetic conditioners in the 1950s tmd some implications to their further development , in Proceedings Symposium on Fundamentals of SoO Conditioning , MF. De Boodt, ed., Gent, Belgium, p. 1150-1159, 17-21 April 1972 BA. Stewart, ed., Soil Conditioners , Soil Sd. Soc. Am. Spec. Publ. 7, Am Soc of... 

Most of the synthetic plastics crrrrently used for packaging are non-degradable and hence not friendly to environment (Pilla, 2011). Bioplastics, on the other hand, are biodegradable which resolves the problem of land filling. After disintegration and composting, bioplastics can be used as fertilizer and soil conditioner (Srinivasa and Tharanathan, 2007). Table 5 hsts the biodegradation period for several bioplastics. 

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