Polyvinyl chloride PVC

[edit] Introduction

Polyvinyl chloride (PVC) sometimes known as ‘vinyl’, is a plastic material that has widespread use in building, transport, electrical, healthcare and packaging. It has been produced widely since 1933 and now accounts for approximately 20% of all plastic manufactured around the world, second only to polyethylene (polyethene). In the UK, approximately 500,000 tonnes are produced each year.

PVC is relatively inexpensive, durable and long lasting. It can be either rigid (uPVC, or unplasticised PVC) or flexible and can be manufactured in a variety of colours or can be transparent.

[edit] Manufacturing process

PVC is derived from common salt (chlorine) and carbon (predominantly from oil or gas).

There are five basic steps in the PVC manufacturing process:

1. The extraction of salt and hydrocarbons.
2. The production of ethylene and chlorine from salt and hydrocarbons.
3. The mixing of chlorine and ethylene to produce vinyl chloride monomer.
4. The polymerisation of vinyl chloride monomer to produce PVC.
5. The blending of PVC polymers with other materials such as plasticisers.

[edit] Applications

[edit] Construction

PVC has extensive use in a construction products. Its strong, lightweight, durable and versatile characteristics make it ideal for products such as window profiles and its flexibility, flame retardant and electrical insulation properties make it ideal for cabling applications.

Examples of PVC construction products include:

• Window and door profiles and conservatories.
• Pipes and fittings.
• Power, data and telecoms wiring and cables.
• Internal and external cladding.
• Cable and ducting.
• Roofing membranes.
• Flooring.
• Wallcoverings.

[edit] Healthcare

For almost 50 years, PVC has been used in a range of healthcare products in pharmaceuticals, surgery, drug delivery and medical packaging. Typical products include:

• Artificial skin.
• Blister and dosage packs for pharmaceuticals and medicines.
• Blood and plasma transfusion sets.
• Blood bags.
• Blood vessels for artificial kidneys.
• Catheters and cannulae.
• Containers for intravenous solution giving sets.
• Containers for urine continence and ostomy products.
• Inflatable splints.
• Overshoes.
• Protective sheeting and tailored covers.
• Shatter-proof bottles and jars
• Surgical and examination gloves.

[edit] Automotive

The high performance and relatively low cost of PVC mean it is used for a range of automotive components including:

• Instrument panels and mouldings.
• Interior door panels and pockets.
• Sun visors.
• Seat coverings.
• Mud flaps.

[edit] Packaging

PVC is flexible, stretchable, light, low cost, transparent,tough and safe. In addition, it does not affect the taste of the food. As a result it is widely used as a packaging material:

• Thermoformed presentation trays for food.
• Packaging for batteries and other electronic goods.
• Packaging for toys.
• Cling film for food.
• Bottles for drinks and toiletries.

[edit] Sustainability

PVC has been criticised by environmental lobby groups, notably by Greenpeace who have run a long-term campaign against the use of PVC. In particular, they are concerned with the use of phthalates as plasticisers and the potential for the release of dioxins in manufacture and disposal.

Greenpeace argue that phthalates in the environment have a suspected ‘reproductive toxicity’, and dioxins are human carcinogens and can have harmful effects on the male reproductive system in animals and humans.

However, the PVC industry counter that the manufacturing and disposal of PVCis very carefully regulated and that these chemicals cannot be released under such circumstances.

There are alternatives for PVC for some purposes, but some of these alternatives poorer performance and very similar environmental characteristics.

uPVC is readily recycled. PVC which has been mixed with additives or other materials can be recycled if it is possible to separate the materials. Alternatively it may be recycled where the composition of PVC and its additives are also desirable in the recyclate.

PVC can be mechanically recycled (ground down and then melted), or can be subject to feedstock recycling, in which it is broken down into its component molecules.

[edit] Related articles on Designing Buildings Wiki.

• Acrylic.
• Architectural fabrics.
• Deleterious materials.
• Millennium Dome.
• The history of fabric structures.
• ETFE.
• Fabric structures.
• Frei Otto.
• Global PVC market analysis and forecast to 2020.
• Plastic.
• Plastic cladding.
• Polycarbonate plastic.
• Polyethylene.
• Polymers.
• PVC market for construction.
• Rubber.
• The development of structural membranes.
• The structural behaviour of architectural fabric structures.
• The thermal behaviour of spaces enclosed by fabric membranes.
• Weatherboarding.