Interpenetrating polymer network morphology

Bandyopadhyay, D., Chakrabarty, D., Mandal, P.K., Goswami, S. Novolac resin-poly(ethyl methacrylate) interpenetrating polymer networks morphology and mechanical and thermal properties. J. Appl. Polym. Sci. 90, 412-420 (2003)... 

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). 

Polymers with Spatially Graded Morphologies Designed from Photo-Induced Interpenetrating Polymer Networks (IPNs)... 

Materials known as interpenetrating polymer networks, IPN s, contain two or more polymers, each in network form (6 9), A practical restriction requires that at least one of the polymer networks has been formed (i.e. polymerized or crosslinked) in the immediate presence of the other. Two major types of synthesis have been explored, both yielding distinguishable materials with different morphologies and physical properties. 

Development of Multiphase Morphology Sequential Interpenetrating Polymer Networks... 

Since the start of modern interpenetrating polymer network (IPN) research in the late sixties, the features of their two-phased morphologies, such as the size, shape, and dual phase continuity have been a central subject. Research in the 1970 s focused on the effect of chemical and physical properties on the morphology, as well as the development of new synthetic techniques. More recently, studies on the detailed processes of domain formation with the aid of new neutron scattering techniques and phase diagram concepts has attracted much attention. The best evidence points to the development first of domains via a nucleation and growth mechanism, followed by a modified spinodal decomposition mechanism. This paper will review recent morphological studies on IPN s and related materials. 

Turner J, Cheng Y-L (2001) Process for preparing interpenetrating polymer networks of controlled morphology. US Patent 6331578... 

Ebdon JR, Hourston DJ, Klein PG (1986) Polyurethane-polysiloxane interpenetrating polymer networks 2. Morphological and dynamic mechanical studies. Polymer 27( 11) 1807—1814... 

Zhou P, Xu Q, Frisch HL (1994) Kinetics of simultaneous interpenetrating polymer networks of poly(dimethylsiloxane-urethane)/poly(methyl methacrylate) formation and studies of their phase morphology. Macromolecules 27(4) 938-946... 

Xiao H et al. (1990) The synthesis and morphology of semi-interpenetrating polymer networks based on polyurethane-poly(dimethylsiloxane) system. J Poly Sci Part A Poly Chem 28(3) 585-594... 

Multicomponent polymeric materials with microheterogeneous mophologies include a number of polymer blends and block copolymers, however, an especially easy way to bring about the desired morphology is through interpenetrating polymer networks. Several papers in the symposium are concerned with IPN s and related materials. 

For many investigators in the sound and vibration damping field, interpenetrating polymer networks, or IPNs, are a new class of polymers capable of exhibiting relatively broad-band damping properties. The purpose of this chapter is to provide an introduction (1,2) to these materials, what they are, how they are made, the kind of morphologies that may be expected, and why they have the properties they have. 

Although chemical structures are used to classify IPNs, the morphology of a polyblend defines it as an interpenetrating polymer network. The net-... 

Urethane-Based IPN Foams. Interpenetrating polymer networks (IPNs) are types of polymer alloys composed of the entanglement of at least two cross-linked components (112). An ideal IPN has essentially no covalent bonds between the polymers. The resulting morphology shows... 

Huelck, V. Thomas, D.A. Sperling, L.H. Interpenetrating polymer networks of poly(ethyl acrylate) and poly(styrene-co-methyl methacrylate). I. Morphology via electron microscopy and II. Physical and mechanical behavior. Macromolecules 1972, 5 (4), 340-348. 

Donatelli, A.A. Sperling, L.H. Thomas, D.A. Interpenetrating polymer networks based on SBR/PS. 1. Control of morphology by level of crosslinking and 2. Influence of synthetic detail and morphology on mechanical behavior. Macromolecules 1976, 9 (4), 671, 676. 

Interpenetrating polymer networks are defined eis a combination of two polymers, each in network form. From a practical point of view, an IPN is comprised of two polymers which cannot be separated chemically, do not dissolve or fiow, and are not bonded together. Like most other multicomponent polymer materials, IPN s usually phase separate due to their very small entropy of mixing. However, the presence of the crosslinks tends to reduce the resulting domain size, hence yielding a unique method of controlling the final morphology. 

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. 

The polymer assisted phase inversion (PAPI) variation of the phase Inversion process utilizes a solution consisting of a solvent and two physically compatible polymers to cast a dense film with a morphology known as an interpenetrating polymer network (IPN). 

Reactive compatibilization, 6. Interpenetrating Polymer Networks, 7. Rheology, 8. Morphology,... 

Hua, FJ, Hu, CP. 2000. Interpenetrating polymer networks of epoxy resin and urethane acrylate resin 2. Morphology and mechanical property. Eur Polym J 36 27-33. 

Kumar, H., Anilkumar, A., and Siddaramaiah. 2006. Physico-mechanical, thermal and morphological behaviour of PU/PMMA semi interpenetrating polymer networks. Polymer Degradation and Stability 91 1097-1104. 

Kim Kim, Y.-S., Kim, S.-C. Properties of polyetherimide/dicyanate semi-interpenetrating polymer network having the morphology spectrum. Macromolecules 32 (1999) 2334-2341. 

OlHar Harismendy, L, del Rio, M., Marieta, C., Gavalda, J., Mondragon, I. Dicyanate ester-po-lyetherimide semi-interpenetrating polymer networks. II. Effects of morphology on the fracture toughness and mechanical properties. J. Appl. Polym. Sci. 80 (2001) 2759-2767. 

Thus the microstructure and the bonding between phases are profoundly affected by the presence of a polymer, especially a film-forming polymer. Further studies of the adhesive and morphological characteristics should make it possible to improve the efficiency of the polymer still further. A somewhat analogous dispersion of rubber latex particles in a plastic matrix is discussed in Section 3.2.2 the related interpenetrating polymer networks discussed in Chapter 8 should also be mentioned. 

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