Polypropylene (PP)

Metallurgy and materials Engineering, University of Punjab, Lahore

1. POLYPROPYLENE ABDUL HANNAN 14MME-S1-319 5 th SEMESTER METALLURGICAL AND MATERIALS ENGINEERING UNIVERSITY OF THE PUNJAB

2. Introduction Polypropylene is also named as polypropene which is a thermoplastic polymer  used in a wide variety of applications including packaging and labeling, textiles (e.g., ropes, thermal underwear and carpets), stationery, plastic parts and reusable containers of various types, laboratory equipment, loudspeakers, automotive.   Natta(professor) produced the first polypropylene resin in Spain in 1954. And now due to fast growing automotive vehicles it is being used vastly in world similarly if we take a look on its properties it has high heat resistance and chemical resisitance . Due to low cost of PP it has huge terms of usage in packaging industries as it contains duality in its characteristics that it is tough as well as flexible in nature.

3. Monomer,polymerization,grades and producers Monomer propylene (C 3 H 6 )n Polymerization method Addition polymerization Grades of polypropylene Homopolymers ( a general purpose grade ) Block polymers ( incorporating of ethylene from 5-15% as it enhances the impact resistance where temp. must be below 20°C ) Random copolymers ( 1-7% ethylene is incorporated selected where low temp. areas and enhanced clarity and flexibility are advantageous ) Name of producers Giulio Natta  and German chemist Karl Rehn in 1954 .

4. Characteristics Density 0.946 g/cm 3 Melting point 160°C Glass transition temp -10°C Commercial availability of Polypropylene are Isotactic and Atactic Behalf of orientation The arrangements in the polymer defines its hidden properties.i.e highly oriented yarn show very less elongation but have very good hardness whereas low orientation manner enhances the elongation as more side chains on the molecules appear which make the polymer flexible . Processing techniques used to produce products with polypropylene Extrusion Blow Molding injection molding Graph

5. Research paper work The addition of polypropylene (PP) fibres to high-performance concrete (HPC) is one way to avoid spalling of concrete under fire conditions. The present work contributes both to the understanding of the way in which fibres act and to optimising the fibre dosage. Pore pressure measurements performed on heated specimens showed that the presence of fibres led to a large decrease in the extent of the pressure fields that build up in the porous network during heating. This effect was also significant at dosages lower than the theoretical percolation threshold. These results are supported by permeability measurements carried out after various heat treatments and for various fibre dosages: they showed the striking effect of fibres from 200°C up, that is, very close to their melting temperature. The role of fibres is discussed through the analysis of concrete microstructure and fibre –matrix interactions as function of heat treatment . (Cement and concrete research volume 31, issue 10 th oct , 2001 )

6. LIMITATIONs PP plastic is the product has a resistance to the addition of paint or ink once the cooling process has completed. This can make the raw material more difficult to work with, especially in applications where the polypropene is being used to create household products, such as shelf organizers. textile manufacturers have to be constantly aware of the temperature of the machinery while the fiber is going through the process. If the fiber becomes too hot, there is a tendency to break and jam on the rollers of many types of textile machinery . Thankyou 