Common Polymers and Additives used for Processing - Introduction to Polymeric Composites with Rice Hulls - page 43

4.1.3 Classifications
The PE family is very large and consists of eleven basic categories based mainly on
its density and branching. Their mechanical properties are dependent largely on
variables such as the extent and type of branching, crystal structure and MW. The
main categories are:
• Ultra-high-MWPE
• Ultra-low-MWPE(orPE-Wax)
• High-MWPE
• HDPE
• High-densitycrosslinkedPE
• CrosslinkedPE
• MDPE
• Linearlow-densitypolyethylene(LLDPE)
• LDPE
• VeryLDPE
• Chlorinatedpolyethylene
According to technology currently being used for the production of polymeric
composites with rice hulls (PCRH), the most common and productive polymers from
the list shown above are LDPE, HDPE and LLDPE. However, technology advances,
and the designers of these polymeric composites may use some of the other grades
as well to achieve better properties for the end products, but will also have to take
the polymer costs into account.
4.2 Polypropylene
PP (also known as polypropene) is a thermoplastic polymer made from the monomer
propylene. An addition polymer, it is rugged and usually resistant to many chemical
solvents, bases and salts. This polymer is used in various applications: packaging,
ropes, textiles, plastic parts, labelling, automotive components, and audio appliances.