Interpenetrating polymer networks three-dimensional

IPN technique leads to the formation of two interpenetrating three-dimensional networks that are not covalently bonded. The cross-linking of at least one of the polymer systems distinguishes an IPN from a chemical blend. 

The fabrication of the material that forms when linear polyimides are mixed or coupled with epoxy resins to form three dimensional interpenetrating networks (IPN) is wrought with problems. These can be viewed from a polymer science aspect, where chemically modifying the structure of the components will result in their compatibility or from an engineering viewpoint where modifying existing fabrication methods and formulations will result in the desired composite materials. The following is a summary of research of epoxy and polyimide combinations to date. 

Studies of preparation and properties of the so-called Simultaneous Interpenetrating Networks (SIN) occupy a special position among these works. SIN is a complex system of two or more three-dimensional network polymers which are chemically not bonded but are inseparable due to mechanical entanglement of chains. A detailed description of the preparation and properties of SIN is given by Lipatov and Ser-geeva . ... 

Obtaining interpenetrating networks (IPNs) is in principle a new method of blending nomnelting and insoluble three-dimensional polymers. IPNs are known to be characterized by a number of thermodynamic and physical-mechanical peculiarities. Application of IPNs based on crosslinked polymers of various chemicsd compositions should produce adhesives with a wide range of properties. 

Li H, Wang H, Wang H, Li B. A novel (2,3,5)-connected double interpenetrating three-dimensional network cadmium coordination polymer with flexible tri(triazole) and dicyanamide ligands. Inorg Chem Commun 2011 14(1) 49-51. 

Nanocomposites consist of a nanometer-scale phase in combination with another phase. While this section focuses on polymer nanocomposites, it is worth noting that other important materials can also be classed as nanocomposites—super-alloy turbine blades, for instance, and many sandwich structures in microelectronics. Dimensionality is one of the most basic classifications of a (nano)composite (Fig. 6.1). A nanoparticle-reinforced system exemplifies a zero-dimensional nanocomposite, while macroscopic particles produce a traditional filled polymer. Nanoflbers or nanowhiskers in a matrix constitute a one-dimensional nanocomposite, while large fibers give us the usual fiber composites. The two-dimensional case is based on individual layers of nanoscopic thickness embedded in a matrix, with larger layers giving rise to conventional flake-filled composites. Finally, an interpenetrating network is an example of a three-dimensional nanocomposite, while co-continuous polymer blends serve as an example of a macroscale counterpart. 

The bond between the polymer and the silane film is formed by a chemical reaction between the functional groups of the silane and a functional group in the polymer. However, good adhesion has also been obtained with silanes that do not contain an organofunctional group such as bis-tri[ethoxysilyl]ethane (BTSE, Table 1). In such cases, it is assumed that the penetration of the polymer into the three-dimensional siloxane network with formation of an interpenetrating network also plays a role in the adhesion mechanism. 

Although all of the examples shown above contain only one type of individual polymer in each, it is possible for interpenetrating networks to form using different nets, although this does not occur as frequently. The nets also do not have to have the same topology - it is possible for a one-dimensional net and a two-dimensional net to become interpenetrated, resulting in a three-dimensional... 

Latex IPNs, by definition, have their origin in emulsion polymerization. Several types of latex IPNs exist. If one blends two kinds of latex particles, followed by film formation and cross-linking of both polymers, the material is called an interpenetrating elastomeric network, TEN. Usually, lENs form a three-dimensional mosaic structure (69,70). 

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