Polypropylene PP semi-crystalline polyolefin

INTRODUCTION
Polypropylene (PP) is a linear hydrocarbon polymer (a polyolefin).

Polypropylene is one of those most versatile polymers available with applications, both as a plastic and as a fiber, in virtually all of the plastics end-use markets.

PROPERTIES
Semi-rigid, translucent, good chemical resistance, tough, good fatigue resistance and good heat resistance.

PP does not present stress-cracking problems and offers excellent electrical and chemical resistance at higher temperatures. While the properties of PP are similar to those of Polyethylene, there are specific differences. These include a lower density, higher softening point (PP doesn't melt below 160 C; polyethylene, anneal at around 100 C) and higher rigidity and hardness. Additives are applied to all commercially produced polypropylene resins to protect the polymer during processing and to enhance end-use performance.

Homopolymers - A General Purpose Grade that can be used in a variety of different applications.

Block copolymers - incorporating 5-15% ethylene, have much improved impact resistance extending to temperatures below -20oC. Their toughness can be further enhanced by the addition of impact modifiers in a blending process.

Random copolymers - incorporate co-monomer units arranged randomly (as distinct from discrete blocks) along the polypropylene long chain molecule. Such polymers typically containing 1-7% ethylene are selected where a lower melting point, more flexibility and enhanced clarity are advantageous.

Psysical properties:
Tensile Strength	30 - 40	MPa
E-modulus	700 - 2300	MPa
Notched Impact Strength	3.0 - 30.0	kJ/m²
Thermal Coefficient of expansion	100 - 150	x 10-6
VicatB Temp	125 - 130	0C
Max Cont Use Temp	80 - 100	0C
Density	0.905	g/cm³

APPLICATIONS

Flexible Packaging
PP is one of the leading materials used for film extrusion and has in recent years benefited versus cellophane, metals and paper on account of its superior puncture resistance, low sealing threshold and competitive price.

Food and Confectioneries Tobacco Clothing

Rigid Packaging
Reusable and collapsible/stackable crates are a great application for PP.

Caps and Closures manufactured of PP have benefited from growth in the PET bottle market, particularly for mineral water containment and that of edible oil.

PP is used to produce bottles for the packaging of a range of products including condiments, detergent and toiletries markets.

PP thin-walled containers are also common. PP competes with PS in this field, offering a cheaper material option.
 
Automotive
In the automotive sector PP is utilised as material solution for automotive interiors. Dashboard is becoming increasingly achievable, PP film cushioning, film skins, and powder slush moulding and even blow moulded parts with integral PP textile covers.

Bumpers, cladding, and exterior trim are also available manufactured from polypropylene. Polypropylene developed for such applications provides good weatherability, processability and impact/stiffness balance.

Consumer Products
Products classified in this sector are Housewares, Furniture, Appliances, Luggage, Toys, Battery Cases and other "durable" items for home.

Fiber
PP Fiber is utilised in a host of applications including tape, strapping, bulk continuous filament, staple fibers, spunbound, and continuous filament.

Industrial
PP is used to manufacture a range of Sheet, Pipe, Compounding and Transport Packaging.

Building&construktion
Some PP is utilised by the construction sector, most notable domestic drainage pipes.