Jul 13, 2012: Polyvinyl Choride (PVC) is a chemical compound of chlorine, carbon and hydrogen. The components of PVC originate from the naturally occurring raw materials of petroleum or natural gas and common salt. The ‘u’ stands for unplasticised and means that the material has not been softened by the addition of chemicals known as plasticizers.
PVC was produced for the first time in 1935 and has been industrially manufactured in large quantities for over 50 years. It has been developed into a material that can offer a wider range of properties and therefore has many different applications. Total PVC productions can be split approximately into the following applications:•55% Construction Industry•16% Packaging History•4% Furniture•4% Cars•2% Electricity Industry•19% Others (including Medical and Horticultural)PVC is a thermoplastic material, PVC can be clear or colored, rigid or flexible, depending on the added compounds and final application that needs to be achieved; For example there exists different PVC grades such as cost or blow film, high impact, wire and cable grade, thermoforming, injection molding, rotational molding etc.
The basic raw material for PVC is derived from salt and oil, Chlorine is manufactured by the electrolysis of sodium chloride, salt. This is why the first PVC manufacturing plants were located close to natural sources of salt.
The electrolysis of salt water produces chlorine. The chlorine is then combined with ethylene that has been obtained from oil. The resulting element is ethylene dichloride, which is converted at very high temperatures to vinyl chloride monomer. These monomer molecules are polymerized forming polyvinyl chloride resin. For example rigid PVC like the one which is used in windows frames normally PVCU (unplasticized), on the other hand flexible PVC is achieved by adding plasticizers such as phthalates.Furthermore, pure poly-chloroethene is unstable when exposed to visible light or UV. In order to modify this disadvantage and make it suitable for different applications antioxidants are added. Some other additives comprise:
Additives in uPVC : Properties achieved
1. Anti-oxidants and other stablizers: Slow down the rate at which polymer degraded by oxygen, visible light or UV radiation
2. Compatibilizers: Enable PVC to be mixed with other plastic recycling.
3. Flame retardants: Reduce flammability of plastic.
4. Pigments: To colour the plastic.
5. Plasticisers: To produce the flexible and manageable plastic.
6. Impact modifiers: To absorb shock without damage.
7. Fillers: Inexpensive, inert materials that simply add bulk to the plastic.There are some of the properties that makes PVC appropriate for several applications:
1.Toughness, Strength.
2.Ease of blending, ease of processing.
3.Flame resistant and fire prevention properties.
4.Excellent electrical insulation properties. This makes it ideal to be used in cables.
5.Impact strength and resistant to bad weather conditions.
6.Resistance to grease, oil and chemicals.
7.PVC is chemically stable and does not de-polymerize.uPVC for DoorsThe basic material properties of uPVC make it ideal for door application. These properties include:•Does not rot or biologically decompose•Is resistant to weathering with low maintenance requirements•Is tough on impact•It retains its shape within normal climatic temperatures•It can be reshaped at high temperature and can therefore be recycleduPVC for WindowsPure uPVC is not quite suitable for window profiles. A small amount of stabilizers and additives are required, the mix of which may differ between manufacturers. The basic material properties of uPVC make it ideal for window application. These properties include:•Does not rot or biologically decompose•Is resistant to weathering with low maintenance requirements•Is tough on impact•It retains its shape within normal climatic temperatures•It can be reshaped at high temperature and can therefore be recycled uPVC for ConservatoriesA uPVC conservatory may also be known as PVC, uPVC or a plastic conservatory.
The most commonly used material in conservatory manufacture is uPVC or unplasticised polyvinyl chloride (ridged plastic). This is also referred to as vinyl in America. The general reason that uPVC is used today in 100,000 of applications including uPVC conservatory manufacture is because uPVC is a thermoplastic – a substance that loses its shape when heated and then becomes ridged again as it cools. Heat shapes uPVC into countless useful forms making it easy to produce uPVC conservatory extrusions.Where additional strength is required the uPVC is reinforced with aluminum or other metals. The reinforcement takes place, for example, in the conservatory roof bars and uPVC conservatory frames or doors.
For more details visit www.sambhavisolutions.com