Polyvinyl Chloride (PVC) — Note

Polyvinyl Chloride (PVC)

1. Introduction

Polyvinyl Chloride (PVC) is a thermoplastic polymer obtained by the polymerisation of vinyl chloride (chloroethene) monomer, CH₂=CHCl. It is widely used in construction, medical devices, and consumer products due to its chemical resistance, durability, and cost-effectiveness.

General formula: (CH₂CHCl)_n

2. Types of PVC

Type	Description	Properties	Uses
Rigid PVC (uPVC)	Unplasticized; no added softeners	Hard, strong, chemically resistant	Pipes, window frames, doors, flooring
Flexible PVC	Contains plasticizers like phthalates	Soft, flexible, durable	Hoses, cable insulation, inflatable products, flooring

3. Methods of Polymerisation

Suspension Polymerisation: Most common industrial method; vinyl chloride suspended in water with initiators ? polymer particles formed.
n CH₂=CHCl → (CH₂CHCl)_n (PVC)
Emulsion Polymerisation: Produces PVC latex for coatings, paints, and adhesives.
Bulk Polymerisation: Rarely used industrially due to heat control challenges.

4. Structure

PVC has a linear chain structure with alternating –CH₂– and –CHCl– units. Chlorine atoms attached to every other carbon increase density, hardness, and chemical resistance.

CH₂=CHCl → –[CH₂–CHCl]_n–

5. Properties

Mechanical: Rigid PVC is strong and stiff; flexible PVC is soft and elastic
Thermal: Softening temperature ~75–105°C; low thermal stability without additives
Chemical: Resistant to acids, alkalis, salts, and most solvents
Electrical: Good insulating properties; used in cables
Processability: Can be molded, extruded, calendared, or made into films

6. Advantages

Excellent chemical resistance
Durable and long-lasting
Versatile: rigid and flexible forms available
Cost-effective and easy to process

7. Limitations

Low thermal stability; requires stabilizers
Can release HCl on burning ? corrosive fumes
Plasticizers in flexible PVC may leach over time
Not biodegradable

8. Applications

Construction: pipes, window frames, flooring, wall panels
Electrical: insulation of wires and cables
Medical: blood bags, tubing, IV containers
Consumer products: inflatable toys, hoses, footwear
Coatings: paints, protective films

9. Summary

Polyvinyl Chloride (PVC) is a versatile polymer available in rigid and flexible forms. Its chemical resistance, durability, and cost-effectiveness make it widely used in construction, medical devices, and electrical insulation. With proper additives, its stability, flexibility, and lifespan can be tailored for diverse applications.

Polyvinyl Chrloride (PVC)

Video Lecture

Study Notes