In chemistry|lang=en terms the difference between copolymer and synthetic
is that
copolymer is (chemistry) a polymer derived from more than one species of monomer while
synthetic is (chemistry) produced by synthesis instead of being isolated from a natural source (but may be identical to a product so obtained).
As nouns the difference between copolymer and synthetic
is that
copolymer is (chemistry) a polymer derived from more than one species of monomer while
synthetic is a synthetic compound.
As an adjective synthetic is
of, or relating to synthesis.