What is the Difference Between Cross Linked Polymer and Linear Polymer?

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The main difference between crosslinked and linear polymers lies in their structure and the forces holding them together. Here are the key differences:

  1. Structure: Linear polymers have long chains of monomers arranged end-to-end, resembling a necklace of beads. In contrast, crosslinked polymers have chains that are connected by covalent bonds, forming a network structure.
  2. Forces: Linear polymers are held together by weaker van der Waals or hydrogen bonding forces. Crosslinked polymers, on the other hand, are tied together via covalent bonding, which is stronger.
  3. Melting Points: Linear polymers typically have high melting points due to the closely packed polymer chains. Crosslinked polymers do not have high melting points; instead, they become a soft material that burns.
  4. Thermoplasticity: Linear polymers are usually thermoplastic, meaning they can be melted and reshaped multiple times. Crosslinked polymers are not thermoplastic and cannot be remolded or reshaped.
  5. Examples: Examples of linear polymers include Teflon and polypropylene, while examples of crosslinked polymers include polyester fiberglass, epoxy resins, and vulcanized rubber.

In summary, linear polymers have end-to-end links and are held together by weaker forces, while crosslinked polymers have covalent bonds between polymer molecules and form network structures.

Comparative Table: Cross Linked Polymer vs Linear Polymer

The main difference between cross-linked and linear polymers lies in the arrangement of their monomer units. Cross-linked polymers have chains that are joined together by a series of covalent bonds, while linear polymers consist of monomers joined together end-to-end, resembling the beads in a necklace. Here is a summary of the differences between cross-linked and linear polymers:

Feature Cross-Linked Polymers Linear Polymers
Chain Structure Closed-loops and branched structures Long chains with monomers connected end-to-end
Degree of Crosslinking Positive value Zero
Examples Epoxy resins, vulcanized rubber, polyester fiberglass Teflon, polypropylene

Cross-linked polymers have a three-dimensional network structure, whereas linear polymers have straight chain structures. Thermoplastics belong to linear polymers, which can be formed, melted, and reformed any number of times, while thermosets and elastomers belong to cross-linked polymers that retain their original shape and cannot be melted or reshaped.