Interpenetrating polymer networks topology

Frisch, K. C. et al., "Topologically Interpenetrating Polymer Networks", Recent Advances in Polymer Blends, Grafts and Blocks, ed. by L. H. Sperling, Plenum Press, N.Y. 19T8-... 

Scheme 2. Pictorial representation of an entanglement 4, an interpenetrated polymer network 5, and a topologically trapped macrocycle in a polymer network 6.

Erisch, H.L., 1993. Macromolecular topology. Metastable isomers from pseudo interpenetrating polymer networks. New J. Chem. 17 697-701. 

An interpenetrating polymer network (IPN) is defined as a combination of two crosslinked polymers, at least one of which has been synthesised [98] and/or crosslinked in the immediate presence of the other. From the topological point of view, IPNs are closely related to pol)nner blends and to block, graft and crosslinked copolymers. From the synthesis point of view, IPNs can be classified, broadly, into two general types (a) sequential IPNs where a polymer network is formed which is then swollen by the monomer, plus a crosslinking agent and an activator, which is then polymerised in situ to form the second network and (b) simultaneous IPNs (SIPN) where the components necessary to form both networks are mixed and polymerised, at the same time, by non-competing mechanisms. If one of the two polymers is linear (uncrosslinked), a semi-IPN results. A homo-IPN results if both the network polymers are identical in chemical composition [98]. 

H. L. Frisch, K. C. Frisch, and D. Klempner, Glass Transition of Topologically Interpenetrating Polymer Networks, Polym. Sci. 14(9), 646 (1974). Topological IPN. Glass Transitions. Polyurethane-based SIN. 

K. C. Frisch, Topologically Interpenetrating Polymer Networks, Pure Appl. Chem. 43, 229 (1975). Topological Interpenetration. Stress/strain behavior, tensile strength, Tg. Polyurethane SINs. 

An Interpenetrating polymer network, IPN, Is defined as a combination of two polymers In network form, at least one of which Is synthesized and/or crossllnked In the Immediate presence of the other. While closely related to other multicomponent polymer materials such as the polymer blends, grafts, and blocks, the IPN s can be distinguished from them In two ways (1) An IPN swells, but does not dissolve In solvents, and (2) creep and flow are suppressed. The IPN topology Is compared with that of other multicomponent polymer structures In Figure 1. 

Multicomponent polymeric materials consist of polymer blends, composites, or combinations of both. A polymer blend has two definitions The broad definition includes any finely divided combination of two or more polymers. The narrow definition specifies that there be no chemical bonding between the various polymers making up the blend. Table 2.5 and Section 2.7 summarize the basic types of polymer blends based on the broad definition primarily these are the block, graft, star, starblock, and AB-cross-linked copolymers (conterminously grafted copolymers), interpenetrating polymer networks, as well as the narrow definition of polymer blends. More complex arrangements of polymer chains in space can be shown to be combinations of these several topologies. 

Frisch HL, Frisch KC, Klempner D. Glass transitions of topologically interpenetrating polymer networks. Polym Eng Sci 1974 14(9) 646-50. 

It is difficult to determine the interpenetration in amorphous porous polymers. Haranczyk et al. set up some non-interpenetration and interpenetration models of porous polymer networks (PPNs) based on the ideal crystalline model with dia topology. They systematically compared the simulated pore diameter, framework density, simulated pore volume, and experimental pore diameter and pore volume of non-interpenetration and interpenetration models of PAF-1 (PPN-6), PPN-4 and other PPNs (PPN-2, PPN-3, PPN-5). The results indicated that for PPN-4, PPN-5 and PPN-6 (PAF-l), the simulated methane adsorption isotherm of the non-interpenetrated structure compared favourably with the experimental data. This strongly supports that the experimental strueture ean be well modeled by the non-interpenetrated dia net. On the eontrary, the experimental data of the pore... 

A third mode of IPN synthesis takes two latexes of linear polymers, mixes and coagulates them, and crosslinks both components simultaneously. The product is called an interpenetrating elastomeric network, lEN. There are, in fact, many different ways that an IPN can be prepared each yields a distinctive topology. 

Interpenetration is not limited to ordered crystalline materials. The polymeric interpenetrating networks are frequently believed to contain mechanically trapped polymer chainsJ" Inteipenetration has effects on the properties of the polymers when compared to their noninterpenetrating counterparts and is important in their applications. It is extremely difficult to define the exact topology of many of these systems, due to their polymeric nature, and the interested reader is recommended to read... 

As for ID nets, there are a number of different ways for 2D networks to interpenetrate. The compound Ag(tcm) (tern = tricyanomethanide),C(CN)J is a coordination polymer composed of 2D chicken-wirelike (6,3) networks. The networks are corrugated and interpenetrate such that discrete layers of doubly interpenetrating networks are formed (Fig. 2a). The mean planes of the interpenetrating sheets in each layer are parallel and coincident, and the topology of interpenetration can be described as 2D 2D parallel interpenetration. The topology of interpenetration can and should be described further (see Ref. [1] for further descriptions of different possible interpenetration topologies). 

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