GATE (TF) Textile 2011 Question Paper Solution | GATE/2011/TF/03

Polypropylene (PP) is a thermoplastic polymer that is commonly used in various applications such as packaging, textiles, and automotive components. The polymerization of polypropylene involves the following steps:

Production of the monomer: Propylene is produced from crude oil refining or natural gas processing.

Polymerization: Propylene is polymerized using a catalyst, typically a Ziegler-Natta catalyst or a metallocene catalyst. The polymerization can occur in either a liquid or a gas phase. In the liquid phase process, the propylene is mixed with a solvent and the catalyst, and the reaction occurs in a stirred reactor. In the gas phase process, the propylene is introduced into a reactor containing the catalyst, which is in the form of a solid powder.

Molecular weight control: The molecular weight of the PP polymer is controlled by regulating the reaction conditions, such as the temperature, pressure, and catalyst concentration.

Stabilization: The PP polymer is stabilized with the addition of antioxidants and stabilizers to prevent degradation during processing and use.

Processing: The PP polymer can be processed into various products, such as fibers, films, and molded parts, using techniques such as injection molding, extrusion, and blow molding.

Overall, the polymerization of polypropylene involves the chemical reaction of propylene monomer using a catalyst, which results in the formation of long polymer chains. The molecular weight and properties of the polymer can be controlled by adjusting the reaction conditions and stabilizing additives are added to prevent degradation during processing and use.

The formation reaction of polypropylene (PP) involves the polymerization of propylene monomer, which is a C3H6 molecule, to form a long chain polymer consisting of repeating units of propylene. The reaction can be catalyzed by various types of catalysts, such as Ziegler-Natta catalysts or metallocene catalysts.
The general chemical equation for the formation of PP can be written as follows:
n(C3H6) → [-CH2-CH(CH3)-]n
where n represents the number of repeating units in the polymer chain.
In this reaction, the double bond between the carbon atoms in the propylene monomer is broken, and the carbon atoms bond with each other to form a long chain polymer. The resulting polymer chain consists of a backbone of repeating units of propylene, which are connected by single covalent bonds.
The polymerization reaction can occur in either a liquid or gas phase, and the conditions, such as temperature, pressure, and catalyst concentration, can be controlled to regulate the molecular weight and properties of the resulting polymer.