聚丙烯为无毒、无臭、无味的乳白色高结晶的聚合物，密度只有0. 90--"0. 91g/cm3，是目前所有塑料中最轻的品种之一。它对水特别稳定，在水中的吸水率仅为0. 01%，分子量约8万一15万。成型性好，但因收缩率大(为1%~2.5%）.厚壁制品易凹陷，对一些尺寸精度较高零件，很难于达到要求，制品表面光泽好。
Polypropylene is a non-toxic, odorless and tasteless milky white high crystalline polymer with a density of only 0.90 - "0.91g/cm3", which is one of the lightest varieties of all plastics at present. It is very stable to water. Its water absorption is only 0.01% and its molecular weight is about 81.15 million. It has good formability, but the shrinkage rate is large (1%~2.5%). Thick-walled products are easy to dent. For some parts with high dimensional accuracy, it is difficult to meet the requirements, and the surface gloss of the products is good.