Technology

CLAY POLYMERIZATION

1. INTRODUCTION


The petrification of clay by lime is an old story; even its mechanism remains unknown. The petrification of sand (clean) by Portland cement begun in the 17nd century. The product was named concrete, an artificial stone. The petrification of clay by Portland cement was and still is impossible, because the concrete remains too soft.

The mechanism is known as a crystallization that give birth to three calcium silicates. The reaction calls for a good quantity of water for the crystallization: it is a petrification under water.

The concept of petrification of clay and clayish materials by lime was introduced to scientific Vietnamese circles begun from the 90’s of the 20th century by the famous professor Platlfort of Bruxelles University, the one that turned the traditional chemistry up and down: the inorganic polymerization is also possible than the organic polymerization. The reaction wipes out any water in the materials, and the petrification forms without water, a clean difference from the crystallization by Portlan.

2. MECHANISM OF INORGANIC POLYMERIZATION

2.1 DIRECT POLYMERIZATION

After Platlfort, Kaolinite crystals have two sheets in each basic crystal: one of silica, and one of alumina, both having a negative charge. By adding a solution of NaOH to the clay, one can turn the alumina sheet to a positive charge. Kaolinite treated crystals become tiny magnets, as small as 10A0. The magnets stick into a hard stone, a real concrete. The reaction forms long polymers without bridges: they are direct


Figure1: Polymerization inorganic direct

2.2 INDIRECT POLYMERIZATION

This reaction aims at linking small particles of clay by using lime as bridges. The Polymers are formed by an indirect way: two negative charges of clay are linked by a positive charge of lime. The mechanism use the force of magnetism, and the linkage forms when any water in materials is pulled out completely


Figure 2: Polymerization: inorganic indirect

3. CONDITIONS

3.1 MATERIALS

Clays is a complex component in which one can find different types of crystals, some of them being friendly with polymerization like Kaolinite (clay K) and halloysite (clay H); some others being neutral like illite (clay I); and some being not supporting polymerization, like montmorillonite (clay M), smectite (clay S), vermiculite (clay V). We prefer using kaolinite and struggle again smectite

3.2 LIME

We would appreciate the hydrolic lime that is able easily to give cation Ca2+ for the reaction

3.3 GEL FOR RAPID POLYMERIZATION

That favours the reaction ending before 2 days instead of 7 days. The gel is made of organic polymers, with a tiny quantity. Some acids are also useful, like sulfuric acid, citronic acid, acetic acid, that support the rapidity of the reaction.

4. BASIC FORMULA.

During 10 years of continuous research, we arrived to a basic formula of indirect polymerization as follows:
P = f(M+m)abc
In which P = is the reaction of polymerization; M is mixture of clay and lime; m is the gel of rapid reaction or equivalents; a is a perfect mixture, b being a high pressure and c being the exposure in the sun.
If these conditions are seriously considered the products can be ensured

5. APPLICATIONS

Inorganic polymers appear to be quite useful in different fields, of our countryside. The first field is construction materials. The second field includes agriculture and aquaculture. The third field is road building. Inorganic polymers would have a bright future in the coming decades