Question

4. What is the meaning of crosslinking as it relates to polymers? a) In terms of tensile strength, melting point etc, how does a crosslinked polymer compare with a non-crosslinked polymer? b) Draw a simple schematic diagram of linear polyethylene and crosslinked polyethylene (chemical structure of ethylene is CH2 - CH2).

Answer 1

Linear polymer chains which formed by polymerization process joined
together to form 3 dimensional network structure ,which are called
crosslinked polymers
a) Cross linked polymers are hard ,brittle . Hence tensile strength
of crosslinked one is lesser than the tensile strength of un cross linked
polymers. Melting point of crosslinked polymers are higher than the
melting point of un crosslinked polymers. This is because each
linear polymer chain is chemically bonded together to form a 3 dimensional
structure

Linear polyethylene +CH₂ - CH2 - CH₂ - CH₂ - CH₂ CH₂ a Linear - Cross linked polyethylene tclt, - CH-CH₂-CH ₂ -CH-CH tn ECH₂ - CH₂ - CH - CH₂ -CH₂-CH - CH, CH) Cross linked.