POLYMER MOLECULES For carbon chain polymers. Many times each carbon atom singly bonds to two adjacent carbons atoms on either side. represented schematically in two dimensions as follows: . the backbone of each chain is a string of carbon atoms.
which is a solid polymeric material . it will transform to polyethylene.POLYMER MOLECULES If the ethylene gas is reacted under appropriate conditions.
POLYMER MOLECULES These long molecules are composed of structural entities called repeat units. which are successively repeated along the chain .
MOLECULAR WEIGHT During the polymerization process not all polymer chains will grow to the same length. this results in a distribution of chain lengths or molecular weights .
MOLECULAR WEIGHT A weight-average molecular weight is based on the weight fraction of molecules within the various size ranges .
the same polymer material can have quite different properties if it is produced with a different molecular weight .MOLECULAR WEIGHT Thus.
Linear Branched Crosslinked Network .
MOLECULAR CONFIGURATION Head to tail configuration Head to head configuration .
MOLECULAR CONFIGURATION Stereoisomerism isotactic configuration syndiotactic configuration atactic configuration .
MOLECULAR CONFIGURATION cis (structure) trans (structure) .
THERMOPLASTIC &THERMOSETTING POLYMERS THERMOPLASTIC Polyethylene Polystyrene poly(ethylene terephthalate) poly(vinyl chloride) vulcanized rubbers Epoxies phenolics polyester resins THERMOSETTING .
COPOLYMERS Random Copolymer Alternating Copolymer Block Copolymer Graft Copolymer .
POLYMER CRYSTALLINITY Arrangement of molecular chains in a unit cell for polyethylene .