Free Radical Polymerization of Styrene Using Solution Process and Bulk Process Essay Example
Lab 1 Report for MATSE 473
Free Radical Polymerization of Styrene using Solution Process and Bulk Process
Date: 1/17/2012
Introduction:
This lab was designed to demonstrate the free radical polymerization of styrene using solution process and bulk process. It demonstrates specifically with the polymerization of styrene monomer to form polystyrene (PS). This lab was also intended to show the difference between solution process and bulk process and how it affects the yield and appearance of the final product.
Polystyrene is a major polymer used for a wide variety of commercial applications, and a vast majority of this polymer is synthesized via free-radical polymerization. The polymerization of styrene is often initiated by thermal generation of radical species. For example, azo-bis-isobutyronitrile (AIBN) thermally decomposes to form 2-cyano-2-propyl radicals that initiate the polymerization of styrene to polystyrene (Scheme 1).
Scheme 1.
AIBN decomposes into 2-cyano-2-propyl radicals
2-cyano-2-propyl radicals react with styrene monomer to form polystyrene
The free radical polymerization is usually terminated by two mechanisms, coupling or disproportionation. Either mechanism involves the reaction between two growing chain ends. In this lab, the reaction is terminated by adding small amount of methanol to the reaction mixture.
Operational Procedure:
Bulk Polymerization: Styrene polymerizations were performed in a round bottom flask with one open arm. 10 ml (96.015 mmol) of dry, oxygen free styrene and 0.2 g (1.218 mmol) of AIBN was added to a 100 ml round bottom flask. The mixtures were then degassed by bubbling through dry N2(g) for 5 minutes. The experimental setup is shown as figure below. The setup of running water is for the purpose of condensing the vapor of reaction mixture back to the reactor. (The nitrogen purge is not shown)
The polymerization was performed in a 100ml round bottom flask
Free Radical Polymerization of Styrene using Solution Process and Bulk Process
Date: 1/17/2012
Introduction:
This lab was designed to demonstrate the free radical polymerization of styrene using solution process and bulk process. It demonstrates specifically with the polymerization of styrene monomer to form polystyrene (PS). This lab was also intended to show the difference between solution process and bulk process and how it affects the yield and appearance of the final product.
Polystyrene is a major polymer used for a wide variety of commercial applications, and a vast majority of this polymer is synthesized via free-radical polymerization. The polymerization of styrene is often initiated by thermal generation of radical species. For example, azo-bis-isobutyronitrile (AIBN) thermally decomposes to form 2-cyano-2-propyl radicals that initiate the polymerization of styrene to polystyrene (Scheme 1).
Scheme 1.
AIBN decomposes into 2-cyano-2-propyl radicals
2-cyano-2-propyl radicals react with styrene monomer to form polystyrene
The free radical polymerization is usually terminated by two mechanisms, coupling or disproportionation. Either mechanism involves the reaction between two growing chain ends. In this lab, the reaction is terminated by adding small amount of methanol to the reaction mixture.
Operational Procedure:
Bulk Polymerization: Styrene polymerizations were performed in a round bottom flask with one open arm. 10 ml (96.015 mmol) of dry, oxygen free styrene and 0.2 g (1.218 mmol) of AIBN was added to a 100 ml round bottom flask. The mixtures were then degassed by bubbling through dry N2(g) for 5 minutes. The experimental setup is shown as figure below. The setup of running water is for the purpose of condensing the vapor of reaction mixture back to the reactor. (The nitrogen purge is not shown)
The polymerization was performed in a 100ml round bottom flask