Density interpenetrating polymer

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. 

Abbreviations y x AFM AIBN BuMA Ca DCP DMA DMS DSC EGDMA EMA EPDM FT-IR HDPE HTV IPN LDPE LLDPE MA MAA MDI MMA PA PAC PB PBT PBuMA PDMS PDMS-NH2 interfacial tension viscosity ratio atomic force microscopy 2,2 -azobis(isobutyronitrile) butyl methacrylate capillary number dicumyl peroxide dynamic mechanical analysis dynamic mechanical spectroscopy differential scanning calorimetry ethylene glycol dimethacrylate ethyl methacrylate ethylene-propylene-diene rubber Fourier transform-infra-red high density polyethylene high temperature vulcanization interpenetrating polymer network low density polyethylene linear low density polyethylene maleic anhydride methacrylic acid 4,4 -diphenylmethanediisocyanate methyl methacrylate poly( amide) poly( acrylate) poly(butadiene) poly(butylene terephtalate) poly(butyl methacrylate) poly(dimethylsiloxane) amino-terminated poly(dimethylsiloxane)... 

Through the use of sequentially polymerized homo-interpenetrating polymer networks, IPN s, a method will be described below to detect changes, if any, in the physical crosslink density, provided that such physical crosslinks actually do contribute to the retractive and swelling forces. 

A. A. Donatelli, L. H. Sperling, and D. A. Thomas, A Semiempirical Derivation of Phase Domain Size in Interpenetrating Polymer Networks, /. Appl Polym. Sci. 21(5), 1189 (1977). Equations for phase domain size in IPNs and semi-I IPNs. Effect of crosslink density, composition, interfacial tension. 

S. C. Kim, D. Klempner, K. C. Frisch, and H. L. Frisch, Polyurethane Interpenetrating Polymer Networks II. Density and Glass Transition Behavior of Polyurethane-Poly(methyl methacrylate) and Polyurethane-Polystyrene IPNs, Macromolecules 9(2), 263 (1976). Polyurethane/Polymethacrylate SIN Polystyrene/Polyurethane SIN. Glass transition and density studies. 

J. R. Millar, Interpenetrating Polymer Networks—Styrene-Divinylbenzene Copolymers with Two and Three Interpenetrating Networks, and Their Sulphonates, J. Chem. Soc., 1311 (1960). Synthesis of IPNs. Swelling Behavior of IPNs. vs. crosslink density. 

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