Interpenetrating networks, elastomeric

A number of variations of the above-mentioned full IPNs have also been stated in the literature. One of them involves having either Polymer I or II as linear (not crosslinked) polymer, in which case it is called semi-IPN. The other variation involves the formation of Polymer I and II simultaneously through two noninterfering polymerization processes (such as stepwise and chain polymerizations) in which case it is called simultaneous IPN (SIN). If a linear polymer is formed simultaneously with a crosslinked polymer, then we have a semisimultaneous IPN (semi-SINS). Still another type is taking a mixture of two linear polymers, and crosslinking both components simultaneously, in which case it is called interpenetrating elastomeric network (lEN). The common feature of... 

This novel class of polymers, together with simultaneous interpenetrating networks (SIN s) and interpenetrating elastomeric networks (lEN s)... 

This chapter will discuss the synthesis, morphology, and mechanical behavior of IPN s. Related materials, in particular the interpenetrating elastomeric networks (lEN s) of Frisch (Frisch and Klempner, 1970 Klempner et a/., 1970 Matsuo et a/., 1970h) will be included for comparison. 

Figure 8.23. Electron micrographs of ultrathin sections of three interpenetrating elastomeric networks. A/U = 70/30 (left), 50/50 (middle),...

Figure 8.24. Temperature dependences of the dynamic storage modulus E and the loss modulus E" of the interpenetrating elastomeric networks. Filled circles observed values. Solid lines calculated for Takayanagi s model 2. Dashed lines component homopolymers. (Klempner et al., 1970.)...

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. 

D. Klempner, Topologically Interpenetrating Elastomeric Networks, Diss. Abstr. Int. B 31(6), 3321 (1970) Univ. Microfilms, Ann Arbor, Mich., Order No. 70-25, 444. Study of lENs based on PU. Ph.D. thesis. 

D. Klempner, H. L. Frisch, and K. C. Frisch, Topologically Interpenetrating Elastomeric Networks, J. Polym. Sci. Part A-2 8, 921 (1970). lENs based on polyurethane. 

Modulus VS Composition. The modulus of IPNs as a function of composition 3rields information about their relative phase continuity. The first such study on polyacrylate/polyurethane latex interpenetrating elastomeric networks (lENs) was carried out by Matsuo and co-workers (Fig. 7) (43). Note that in the midrange of composition, the modulus begins to follow the parallel Takayanagi model (44). This suggests that the stiflfer acrylic phase is becoming a continuous phase, as predicted from percolation models of three-dimensional mosaics of compressed spheroidal structures. 

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). 

According to the mode of synthesis, IPNs are distinguished into five different types (i) sequential IPNs, (ii) simultaneous IPNs, (iii) interpenetrating elastomeric networks, (iv) thermoplastic IPNs and (v) gradient IPNs ... 

Synthesis routes (a) and (b) above are idealizations, and many permutations of the general idea exist, particularly in patent literature. " IPN s have been synthesized by bulk, suspension and latex methods. For the latter, two variations are still possible the first method places both networks in a single latex particle, called a latex IPN, and the second method is called interpenetrating elastomeric networks, lEN s, where two different latexes are mixed, coagulated and subsequently crosslinked. ... 

Interpenetrating elastomeric network Intumescent flame retardant Interpenetrating homopolymer network Elastomerie eopolymer from isobutene and isoprene (ANSI/ASTM, lUPAC) see also Butyl, GR-I, PlBl Poly(isobutylene) see also PIB Intermediate molecular weight Isophthalic acid... 

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