Polypropylene

LEARN IN BRIEF POLYPROPYLENE PLASTIC..

1. POLYPROPYLENE PRESENTED BY- MANNU KUMAR B.TECH 4 TH YR PLASTIC ENGINEERING CIPET LUCKNOW CIPET LUCKNOW

2. Polypropylene Introduction Polypropylene (PP) is a linear polymer, composed of repeating units of isopropane. The main attractive features of PP are - Exceptional flex life, - Good surface hardness, - High chemical resistance, - Good stability in boiling water, - Excellent electrical property - Long-life integral hinge application .

3. PP is prepared by using Ziegler type catalyst – titanium tri chloride with aluminium tri ethyl, aluminium tri butyl, or aluminium di ethyl chloride in naphtha under nitrogen atmosphere to form slurry consisting of 10% catalyst and 90% naphtha. The molecular weight can be controlled by using hydrogen as a chain transfer agent. In suspension process, propylene is charged into the polymerization vessel under pressure while the catalyst and the reaction diluent are metered in separately. Preparation of Polypropylene

4. PP is a linear polymer with little or no branching. Methyl group in the chain leads to increase in melting point and chain stiffening. The tertiary carbon atom provides a site for oxidation so that the polymer is less stable than PE in the presence of oxygen. Methyl group leads to products of different tacticity. Commercial polymers are usually about 90-95% isotactic. Structure Property Relationship

5. tacticity Isotactic CORPORATE TRAINING AND PLANNING Syndiotactic Atactic

6. Properties of isotactic PP Compare to Polyethylene It has lower density (0.90 gm / cc). It has a higher softening point and hence a higher maximum service temperature. Articles can withstand boiling water and can be subjected to steam sterilizing operations. It has a higher brittle point. It is more susceptible to oxidation. Atactic PP Atactic PP is an amorphous some what rubbery in nature. Commercial polymer is usually 90-95% isotactic and rest is blocks of atactic and syndiotactic structures.

7. General Properties Chemical properties No solvent affects PP at room temperature. Polypropylene will dissolve in Decaline at 130°C. Aromatic and chlorinated solvents often swell polymer at elevated temperature. Strong oxidizing acids slowly attacks the resin (fuming HNO 3 ) Electrical properties PP is an excellent insulator due to its non-polarity. It is used in many molded products, as well as in winding coils and transformers. Flammability PP burns slowly and can be identified by an odour of crude oil. Flame–retardant grades are available for specific electrical applications. Mechanical properties Commercial grades of PP is tough and having good impact resistance. PP becomes more brittle than many other thermoplastics at zero temperature.

8. Additives for Isotactic PP Fillers About 3% of PP compounds are filled with talc. Talc filler improves stiffness and heat deformation resistance. Rubbers Particularly butyl rubber is used to reduce the brittleness of PP Carbon black To improve the resistance to UV light, carbon black is used as a light screener Antioxidants Antioxidants are necessary for prevention from adversity of oxidation .

9. Processing techniques Injection Molding Recommended processing temperatures are in the range of 210 to 275°C. Injection pressures are of 150 to 180 MPa depending on the grade of the material. Because of crystallanity there is high molding shrinkage and is reasonably uniform in all directions. Extrusion Blow moulding

10. applications Automotive PP is used in bumpers, steering wheel covers, profiles, consoles, door pockets, radiator grills, spoilers, rubbing strips Packaging PP is used in packaging for goods wrapping, sleeping bags, films for packing tobacco products, candy, cosmetics, contact lens cases, first aid cases, drums Electrical / Electronics PP is used in cable connectors and fittings, cable and wire coatings, industrial lights

11. Multilayer PP coating for Offshore applications Car Dashboard and Bumper Coffee Maker and Toaster PP furniture

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