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Polyethylene (PE)
Polyethylene is a thermoplastic polymer consisting of long chains produced by combining the ingredient monomer ethylene. The ethylene actually converts to ethane as it takes its place in a polymer and straight sections of the polymer are the same structure as the simple chain hydrocarbons, e.g., propane, decane and other straight single-bonded carbon chains. As with any polymer, the structure of the resulting substance defies molecular description due to cross branching of the chains.
HDPE (High Density polyethylene) is defined by a density of greater or equal to 0.941 g/cm3. HDPE has a low degree of branching and stronger intermolecular forces and tensile strength.
Polypropylene (PP)
Polypropylene (PP) is a thermoplastic from the polyolefin group. It is a semi-rigid, translucent polymer with good toughness and weather resistance properties, low water absorption and is easily moulded to desired shapes. PP is a largely non-polar, partially crystalline thermoplastic with a crystallinity of 60 to 70% and a density of 0.90 to 3 0.91 g/cm which is amongst the lowest for all plastics.
It is generally available in three advanced forms:
PP Homopolymer (PP-H): Produced by a continous chain of polypropylene units which results in a high stiffness material. Advanced homopolymer types like beta nucleated PP, are used to make piping systems and sheets.
PP Copolymer (PP-C): Produced by adding 4-15% ethylene to the polypropylene gives much improved impact strength and considerably lowers the brittle point to below normal service temperatures i.e. -15°C to -20°C.
PP Random Copolymer (PP-R): Random copolymer polypropylene is a clear, semi-crystalline polymer which exhibits high stiffness, better impact strength and good electrical insulation properties.
Other options in PP include fire retardant and electro-conductive grades. PP can also be UV stabilized.
Polyvinylidene Flouride (PVDF)
Polyvinylidene Fluoride (PVDF), the homopolymer of 1, 1-difluoroethylene, is a tough engineering thermoplastic that offers a unique balance of performance properties. The unique structure of alternating units of methylene and difluoromethylene, create a polymer with high crystallinity combined with a high polarity, resulting in a sharp melting point. It has the characteristic stability of fluoropolymers while retaining the properties of a conventional thermoplastic material. KYNAR FLEX ® resins are a series of PVDF based copolymers, similar to KYNAR ® homopolymer resins in purity and chemical resistance, but having additional chemical compatibility in high pH solutions, increased impact strength at ambient and low temperatures, and increased clarity. |
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