Simultaneous interpenetrating networks synthesis

The first type, termed sequential IPN s, involves the preparation of a crosslinked polymer I, a subsequent swelling of monomer II components and polymerization of the monomer II in situ. The second type of synthesis yields materials known as simultaneous interpenetrating networks (SIN s), involves the mixing of all components in an early stage, followed by the formation of both networks via independent reactions proceeding in the same container (10,11). One network can be formed by a chain growth mechanism and the other by a step growth mechanism. 

Figure 1. The synthesis of sequential IPN above and simultaneous interpenetrating networks, SIN, below. For the synthesis of SIN, two different reactions operate simultaneously such as condensation polymerization and addition polymerization. Reproduced with permission from Ref. 23. Copyright 1981, Plenum Publishing.

There are several techniques for producing polymer mixtures for further processing into articles by the reactive (chemical) molding methods simultaneous formation of two polymeric systems with mutual entanglement of their chains and the appearance of so-called interpenetrating networks synthesis of the second polymer within an expanded network of the initial polymer incorporation of oligomers into a polymer matrix as a temporary plasticizer followed by polymerization. 

Synthesis, in the one pot, of two separately reacting systems that form networks independently of one another but, because of their proximity, interpenetrate. This is a simultaneous interpenetrating network. 

This indicates a simultaneous interpenetrating network, where Cn was formed by one reaction (say, addition), C22 was formed independently by another reaction (say, condensation), and the two networks are simultaneously polymerized. Without brackets a sequential synthesis of an interpenetrating polymer network is indicated ... 

N. Devia-Manjarres, Synthesis and Characterization of Simultaneous Interpenetrating Networks Based on Castor Oil Elastomers and Polystyrene, Diss. Abstr. Int. B 39(8), 3972 (1979). Castor oil-polyester/PS SIN. Synthesis, morphology, mechanical behavior. Ph.D thesis. 

N. Devia, J. A. Manson, L. H. Sperling, and A. Conde, Simultaneous Interpenetrating Networks Based on Castor Oil Elastomers and Polystyrene. 2. Synthesis and Systems Characteristics, Macromolecules 12(3), 360 (1979). Synthesis and Processing of castor oil-polyester/PS SINs. Rubber-toughened plastics and reinforced elastomers. 

P. R. Scarito and L. H. Sperling, Effect of Grafting on Phase Volume Fraction, Composition, and Mechanical Behavior, Epoxy/Poly(n-butyl acrylate) Simultaneous Interpenetrating Networks, Polym. Eng. Sci. 19, 297 (1979). Epoxy/poly(n-butyl acrylate) SINs. Synthesis, morphology, mechanical behavior. Molecular mixing, effect on Tg in each phase. 

Over the years, people have discovered many different ways of synthesizing IFN s. Figure 2 Illustrates the sequential IPN synthesis, top, and the simultaneous Interpenetrating network, SIN, synthesis, bottom. In the sequential synthesis, polymer network I Is swollen with monomer II plus crosslinker and activator, and polymerized In situ. The SIN synthesis begins with a mutual solution of both monomers or prepolymers and their respective crosslinkers, which are then polymerized simultaneously by noninterfering modes, such as stepwise and chain polymerizations. These methods have been used In the bulk, suspension, and latex states. Each will yield a distinguishable composition, even for the same polymer pair. 

Figure 1. Simultaneous interpenetrating network (SIN) synthesis based on botanical oils. ...

An interpenetrating polymer network, IPN, is defined as a combination of two polymers, both of which are crosslinked. Most IPN s are formed by synthesizing and/or crosslinking one network in the immediate presence of the other. Formed with covalent crosslinks, IPN s are thermoset, and do not flow or dissolve in ordinary solvents. Two main synthesis paths are illustrated in Figure 1 (a) polymer network I is synthesized, and monomer II plus crosslinker and activator are swollen in and polymerized in situ. This is called a sequential IPN (b) if both monomers or prepolymers are synthesized simultaneously by independent but non-interfering routes, the product is called a simultaneous interpenetrating network, SIN. ... 

An interpenetrating polymer network (IPN) is an intimate assembly of two polymers in network form, one of which is usually either prepared or crosslinked in the presence of the other. Typically, the initial polymer network is. swollen in the presence of the second monomer together with a crosslinking agent, and the second monomer allowed to polymerise and crosslink. Alternatively, simultaneous. synthesis is possible in which the monomeric components of both networks are first mixed and then allowed to polymerise. 

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]. 

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. 

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 ... 

---