Compléter The origin of plasticsVersion en ligne Technologies for spanish speakers par Miriam Cano Cano 1 monomers coal raw chemical Natural polymer carbon petroleum origin resins synthetic Synthetic Plastics are materials made up of long molecules ( ) which are a combination of and hydrogen atoms . A set of many monomers forms a . Depending on their they can be : . - plastics , obtained directly from materials found in nature , such as rubber or . . - plastics made by processes from raw materials as , and natural gas . Most of plastics we use are .