interpenetrating polymer network (IPN)

https://doi.org/10.1351/goldbook.I03117
Polymer comprising two or more networks that are at least partially interlaced on a molecular scale but not covalently bonded to each other and cannot be separated unless chemical bonds are broken.
Note:
A mixture of two or more preformed polymer networks is not an IPN.
Source:
PAC, 2007, 79, 1801. (Definitions of terms relating to the structure and processing of sols, gels, networks, and inorganic-organic hybrid materials (IUPAC Recommendations 2007)) on page 1814 [Terms] [Paper]