A plastic bag is made of polymers, long chains of individual molecules called monomers. When a sharp pencil pierces the bag the polymer chains separate without breaking. The chains of molecules then squeeze tightly around the pencil creating a seal that prevents it from leaking.
find use in our everyday life, from water bottles and Tupperware to tires for
automobiles. The word polymer
is derived from the Greek root poly-, meaning many, and mer, meaning part or
segment. Many of the same units (or mers) are connected together to form a long
chain or polymer.
are of two types: Polymers such as starch, proteins and DNA occur in Nature,
and are called Natural polymers. Synthetic polymers are derived from petroleum
oil and made by scientists and engineers. Examples of synthetic polymers
include nylon and plastic.
repeating chains can be linked together to form a cross-linked polymer, which
may become branched and become a Branched chain polymer. As the degree of cross
linking in the polymer increases, the polymer usually increases in rigidity and
toughness. This is why we see plastics that have different degrees of hardness
from a plastic bag to a hard-plastic baseball bat.
HTHT @ Home Science Experiment and learn about polymers: