Testing of polyethylene, polypropylene and olefin copolymers for branch length and frequency.
Polyolefin manufacturers control the branching of their materials to precisely control various properties associated with material processing and the required end use. The use of various catalysts and comonomers allow for substantial changes in the amount and type of branching.
- Low density Polyethylene (LDPE) has a high level of branching.
- High density polyethylene (HDPE) has minimal branching.
- Linear low density polyethylene (LLDPE) has significant short branches
- Samples are dissolved in heated deuterated o-dichlorobenzene and 1,2,4-Trichlorobenzene.
- Quantitative 13C NMR is performed hot to ensure dissolution.
- The spectra is analyzed for signals attributed to terminal methyl carbons (branch points) and for signals related to branch length from 1 to 6 carbons (branch length capabilities can vary depending on signal quality).
We require approximately 300 milligrams of unfilled polymer to complete the testing. If your polymer contains a filler, we will filter the sample to remove that before analysis.
This testing may be applicable to multiple polyolefin polymers and copolymers. We’ve tested a large variety. Contact us if you would like to know if we can apply this technique to your material.