Note 1 - Modul 1

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COAGULATION OF LATEX GROUP 5

S2

NURUL SYAFIQAH

2018661434

SAKINAH MAWADDAH

2018636662

WAN NUR ARINA ATHILAH

2018684392

YASMIN ATHIRAH

2018257362

ZUR AIN

2018415028


PROBLEM STATEMENT LATEX ARE EASY TO COAGULATE, SO HOW TO PREVENT IT?


CONCEPT OF LATEX COAGULATION 

The milky fluid from tapped rubber trees is called latex.

Conversion of latex to the solid form is known as coagulation.

Latex is a colloidal solution containing an aqueous suspension of rubber particles.

Each rubber particles in latex has a negatively charged protein membrane, making it repel to each other and preventing the rubber polymers from combining together.

Hence, latex remains in liquid form.


Rubber particles which has negatively charged membrane repel each other preventing from coagulation.


COAGULATION OF LATEX ďƒ˜

Coagulation of rubber can be speeded up by addition of acids.

Acid which consist of hydrogen ions is added into the latex. The hydrogen from acids neutralize the negatively charged protein membrane. The rubber particles collide with each other causing the protein membrane of the rubber particles breaks. Therefore, rubber molecules clumps together forming a coagulated latex. ďƒ˜

Besides, coagulation of latex also can occurs without addition of acids by exposing the latex to air for a few days.

Bacteria from the air enter the latex. The growth of bacteria produces in latex produce organic acids and the hydrogen ions from the acids produced neutralizes the negative charge on the rubber particles.


PROPOSE SOLUTION Coagulation of latex can be prevented by the addition of aqueous ammoni,NH 3. 

This is because hydroxide ions from aqueous ammonia neutralize the acids produced by the bacteria.

The negative charges on the membranes of rubber particles are maintained.

Therefore, coagulation of latex prevented.

Besides ammonia, other basic solution also can be used to prevent from coagulation of latex. In order to prevent from coagulation, hydroxide ions in any basic solution is needed. Instead of use strong base, weak base is chosen as a medium to prevent coagulation of latex because it is partially ionized and can produce hydroxide ions. Hence, the positively-charged hydrogen ion, H ⁺ produced by bacteria can be neutralized by negatively-charged hydroxide ion, OH ⁻ from the basic solution.


WHY DO WE NEED TO PREVENT LATEX FROM COAGULATION? ď ś

Rubber tapping

On the final product of rubber tapping, additional chemicals added to the latex cup to preserve the latex longer. Ammonia,NH3 solution helps to prevent natural coagulation and allows the latex remain in its liquid state.


CONCLUSION The surface of the latex particle are charged, which creates forces of repulsion between them that keep them from coagulating. In the coagulation process, formic acid neutralizes these charges, thereby eliminating the forces of repulsion. Thus, it fasten the coagulation of latex. It will be easier to process it to form a product such as eraser, tyre and rubber ball. It is contradict when using using ammonia because it prevent the coagulation of latex. It will form a liquid latex that usually used as adhesive binding and carting.


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