Polypropylene is a non-toxic, odorless, and tasteless milky white high crystallinepolymer with a melting point of 164~170° C, a density of 0.90-0.91g/ cm%, and a molecularweight of about 80,000 to 150,000. It is one of the lightest of all plastic varieties at present. It is particularly stable to water, and its water absorption rate in water for 24 hoursis only 0.01%6.
