NATIONAL TEXTILE UNIVERSITY, FAISALABADFACULTY
OF ENGINEERING AND TECHNOLOGY DEPARTMENT OF
MATERIAL
Submitted by
Submitted to
Department
Date
Course code
Usman haider
Dr wasif
Polymer engneering
19-12-2023
PE-2106
Experiment No: 8
Objective: Prepation of polystyrene by Emulsifier
Abstract:
This laboratory report details the synthesis of polystyrene through emulsion polymerization.
The procedure involves the emulsification of styrene monomer in water using an emulsifying
agent. The emulsion is initiated through the addition of a suitable initiator, leading to the
growth of polystyrene chains. Throughout the process, temperature control and initiator
dosage are carefully managed to achieve the desired polymer properties. The reaction is
terminated at the appropriate stage, and the resulting polystyrene latex is recovered, often
through coagulation and separation techniques. The collected latex is subsequently dried to
obtain the final polystyrene polymer. This report outlines the experimental setup, procedure,
and key considerations in the synthesis process, providing insights into the successful
preparation of polystyrene via emulsion polymerization in the laboratory setting
Introduction:
Polystyrene, a versatile and widely used synthetic polymer, finds applications in various
industries ranging from packaging materials to consumer goods. Its production often involves
emulsion polymerization, a method known for its efficiency and scalability. Emulsion
polymerization is particularly advantageous for the synthesis of polystyrene due to its ability to
yield high molecular weight polymers with controlled properties.The process of emulsion
polymerization involves the dispersion of hydrophobic monomers, such as styrene, in an
aqueous medium with the aid of an emulsifying agent. This dispersion forms stable emulsions,
preventing the coalescence of monomer droplets and facilitating controlled polymerization. of.
Fig 1 polystyrene
This laboratory report outlines the systematic preparation of polystyrene through emulsion
polymerization. By elucidating the experimental setup, methodology, and key parameters, this
study aims to provide a comprehensive understanding of the factors influencing the successful
synthesis of polystyrene in a controlled laboratory environment. The insights gained from this
investigation contribute to the optimization of production processes, ensuring the
reproducibility and quality of polystyrene for diverse industrial applications
Apparatus :
Reaction Vessel:A suitable reaction vessel equipped with a stirring mechanism to facilitate
thorough mixing of reactants. The vessel should be capable of maintaining a controlled
temperature throughout the polymerization process.
Condenser:A water-cooled condenser to prevent the escape of volatile substances and
maintain a closed system during the polymerization reaction.
Thermometer:A calibrated thermometer to monitor and control the temperature of the
reaction, ensuring optimal conditions for polymerization.
Emulsifying Agent:An emulsifying agent or surfactant, such as sodium dodecyl sulfate, to
stabilize the emulsion and disperse the hydrophobic monomer in the aqueous medium.
Styrene Monomer:High-purity styrene monomer, the precursor for polystyrene, to be added to
the emulsion.
Initiator:A suitable chemical initiator, such as potassium persulfate or AIBN (azo-bisisobutyronitrile), to initiate the polymerization reaction
Procedure:
Preparation of Emulsion: Place a clean and dry reaction vessel equipped with a stirring
mechanism. Add a prede 60ml amount of water to the vessel. Introduce the selected
emulsifying agent (e.g.poly vinyl alchol) to the water while stirring to form a stable emulsion .
Inert Atmosphere Setup: Purge the reaction vessel with an inert gas (e.g., nitrogen) to create
an oxygen-free environment, preventing undesired side reactions.
Monomer Addition: Gradually introduce the styrene 10ml monomer into the emulsion while
maintaining constant stirring. Continue stirring to ensure uniform dispersion of the monomer
droplets in the emulsion.
Initiation: Add the chosen initiator (e.g.5ml benzyl peroxide) to initiate the polymerization
reaction.Maintain a controlled temperature throughout the reaction, typically in the range of
50-70°C, depending on the initiator and reaction conditions.
Polymerization: Observe the gradual formation of polystyrene chains as the polymerization
proceeds. Adjust the stirring speed and temperature as needed to optimize the reaction
kinetics
Product Separation: Separate the resulting polystyrene latex from the aqueous medium using
appropriate separation techniques such as coagulation or centrifugation.
Drying: Collect the separated polystyrene latex and transfer it to a drying apparatus. Dry the
polystyrene product to remove any remaining water.
Fig 2 polystyrene
Application:
Polystyrene, a versatile polymer with a wide range of beneficial properties, finds
applications in various industries. Some of the key applications of polystyrene
include:
Packaging Materials:Expanded polystyrene (EPS) is commonly used for packaging materials,
including protective packaging for fragile items and disposable foodservice items like foam cups
and trays.
Insulation:EPS is an excellent thermal insulator, making it a preferred material for insulation
in construction, packaging, and appliances.
Disposable Products:Polystyrene's low cost and ease of manufacturing make it suitable for
the production of disposable products such as cutlery, plates, and food containers.
Medical Applications:High-impact polystyrene (HIPS) is used in the production of medical
devices, including petri dishes, sample cups, and components of medical equipment.
Consumer Goods:Polystyrene is employed in the manufacturing of various consumer goods,
including toys, CD cases, and electronic housings