Open main menu
Home
Random
Recent changes
Special pages
Community portal
Preferences
About Wikipedia
Disclaimers
Incubator escapee wiki
Search
User menu
Talk
Dark mode
Contributions
Create account
Log in
Editing
Cross-link
(section)
Warning:
You are not logged in. Your IP address will be publicly visible if you make any edits. If you
log in
or
create an account
, your edits will be attributed to your username, along with other benefits.
Anti-spam check. Do
not
fill this in!
==Measuring degree of crosslinking== Crosslinking is often measured by [[swelling capacity|swelling]] tests. The crosslinked sample is placed into a good solvent at a specific temperature, and either the change in mass or the change in volume is measured. The more crosslinking, the less swelling is attainable. Based on the degree of swelling, the Flory Interaction Parameter (which relates the solvent interaction with the sample), and the density of the solvent, the theoretical degree of crosslinking can be calculated according to Flory's Network Theory.<ref>Flory, P.J., "Principles of Polymer Chemistry" (1953)</ref> Two ASTM standards are commonly used to describe the degree of crosslinking in thermoplastics. In ASTM D2765, the sample is weighed, then placed in a solvent for 24 hours, weighed again while swollen, then dried and weighed a final time.<ref>{{cite web|url=http://www.astm.org/Standards/D2765.htm|title=ASTM D2765 - 16 Standard Test Methods for Determination of Gel Content and Swell Ratio of Crosslinked Ethylene Plastics|website=www.astm.org|access-date=1 April 2018}}</ref> The degree of swelling and the soluble portion can be calculated. In another ASTM standard, F2214, the sample is placed in an instrument that measures the height change in the sample, allowing the user to measure the volume change.<ref>{{cite web|url=http://www.astm.org/Standards/F2214.htm|title=ASTM F2214 - 16 Standard Test Method for In Situ Determination of Network Parameters of Crosslinked Ultra High Molecular Weight Polyethylene (UHMWPE)|website=www.astm.org|access-date=1 April 2018}}</ref> The crosslink density can then be calculated.
Edit summary
(Briefly describe your changes)
By publishing changes, you agree to the
Terms of Use
, and you irrevocably agree to release your contribution under the
CC BY-SA 4.0 License
and the
GFDL
. You agree that a hyperlink or URL is sufficient attribution under the Creative Commons license.
Cancel
Editing help
(opens in new window)