Interpenetrating polymer networks composition

Fujiki M, Furuta D, Naito M (2004) Manufacture of semi-IPN (interpenetrating polymer network) composite and the composite made of crosslinkable siloxane and radically polymerized polymer. JP Patent 2 004 263 062... 

Chen, S., Wang, Q., Wang, T., Pei, X. Preparation, damping and thermal properties of potassium tltanate whiskers filled castor oil-based polyurethane/epoxy Interpenetrating polymer network composites. Mater. Des. 32, 803-807 (2011)... 

Semi-interpenetrating polymer network composite membranes consisting of poly (styrene-sulfonic acid) and poly(vinylidene fluoride) (PVDF) were developed jointly at the University of Southern CaUfomia and the Jet Propulsion Laboratory (Prakash et al., 2004). The methodology made use of the thermally initiated radical interpolymerization of styrene that was absorbed into a PVDF film with subsequent sulfonation of the resultant polystyrene. Membranes had a proton conductivity of 0.06-0.09 S/cm with three times lower methanol crossover in a DMFC at 55°C and 0.5 M methanol. 

The ultimate goal of bulk modification endows with the polymer-specific surface composition or a specific property for a given application. The bulk modification can be classified into blending, copolymerization, interpenetrating polymer networks (IPNs), etc. 

The use of interpenetrating donor-acceptor heterojunctions, such as PPVs/C60 composites, polymer/CdS composites, and interpenetrating polymer networks, substantially improves photoconductivity, and thus the quantum efficiency, of polymer-based photo-voltaics. In these devices, an exciton is photogenerated in the active material, diffuses toward the donor-acceptor interface, and dissociates via charge transfer across the interface. The internal electric field set up by the difference between the electrode energy levels, along with the donor-acceptor morphology, controls the quantum efficiency of the PV cell (Fig. 51). 

This is a theoretical study on the structure and modulus of a composite polymeric network formed by two intermeshing co-continuous networks of different chemistry, which interact on a molecular level. The rigidity of this elastomer is assumed to increase with the number density of chemical crosslinks and trapped entanglements in the system. The latter quantity is estimated from the relative concentration of the individual components and their ability to entangle in the unmixed state. The equilibrium elasticity modulus is then calculated for both the cases of a simultaneous and sequential interpenetrating polymer network. 

This is a theoretical study on the entanglement architecture and mechanical properties of an ideal two-component interpenetrating polymer network (IPN) composed of flexible chains (Fig. la). In this system molecular interaction between different polymer species is accomplished by the simultaneous or sequential polymerization of the polymeric precursors [1 ]. Chains which are thermodynamically incompatible are permanently interlocked in a composite network due to the presence of chemical crosslinks. The network structure is thus reinforced by chain entanglements trapped between permanent junctions [2,3]. It is evident that, entanglements between identical chains lie further apart in an IPN than in a one-component network (Fig. lb) and entanglements associating heterogeneous polymers are formed in between homopolymer junctions. In the present study the density of the various interchain associations in the composite network is evaluated as a function of the properties of the pure network components. This information is used to estimate the equilibrium rubber elasticity modulus of the IPN. 

Vidal F, Fichet O, Laskar J, Teyssie D. (2006) Polysiloxane - acetate butyrate cellulose Interpenetrating Polymers Networks close to true IPNs on a large composition range. Part II. Polymer 47 3747-53... 

There are at least four general types of combinations of crosslinked (x) and linear (1) polymers in a two-component system both components crosslinked (xx), one or the other component crosslinked (lx or xl), and both components linear (11). Where at least one of the components has been polymerized in the presence of the other, the xx forms have often been called interpenetrating polymer networks (IPN), the lx and the xl forms termed "semi-IPNs", and the last, linear or in situ blends. There are also a number of ways in which the components can be formed and assembled into a multicomponent system. Sequential IPNs are prepared by swelling one network polymer with the precursors of the second and polymerizing. Simultaneous IPNs are formed from a mixture of the precursors of both components polymerization to form each component by independent reactions is carried out in the presence of the other precursors or products. Usually, the simultaneous IPNs that have been reported are extremes in the component formation sequence the first component is formed before the second polymerization is begun. Sequential IPNs and simultaneous IPNs of the same composition do not necessarily have the same morphology and properties. 

In this regard, preferential use of NIPU in hybrid systems based on copolymerization and modification of other polymer materials seems promising. Using an interpenetrating polymer network (IPN) principle in production of composite materials provides a unique possibility to regulate their both micro- and nanostructures and properties. By changing the IPN formation conditions (sequence of polymerization processes, ratio of components, temperature, pressure, catalyst content, introduction of filler, ionic group, etc.), it is possible to obtain a material with desirable properties. 

The structures listed in Table 1.6 are divided into three categories Short sequences, Long sequences, and Networks. Within the first category a sequence of placement of individual CRU is considered, within the second the placement of long sequences of CRU defines the copolymer type, while to the third belong crosslinked networks, crosslinked polymers, and chemical-type interpenetrating polymer networks. The network is a crosslinked system in which macromolecules of polymer A are crosslinked by macromolecules of polymer B [Sperling, 1992]. The composition can be expressed as, e.g., Woc -co-poly(butadiene/styrene) (75 25 wt%), or gra/i-co-poly[isoprene/ (isoprene acrylonitrile)] (85 15 mole %). 

Ha, H.J., Kil, E.H., Kwon, Y.H., Kim, J.Y., Lee, C.K., Lee, S.Y., 2012. UV-curable semi-interpenetrating polymer network-integrated, highly bendable plastic crystal composite electrolytes for shape-conformable aU-solid-state lithium ion batteries. Energy Environ. Sci. 5, 6491-6499. 

Full or semi-interpenetrating polymer networks (IPNs) can be designed to exhibit shape memory effects. In an IPN system, the network properties play an important role in controlling the shape memory performance. The hydro-philicity, transition temperatures, and mechanical properties of IPNs can be conveniently adjusted through variation of network compositions to match the desired applications. 

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