Polymer network structure

Dusek K (1971) in Shompff AJ, Newmann S (eds) Polymer Networks. Structure and Mechanical Properties. Plenum Press, New York, p245... 

Serious deviations of the polymer network structure from the ideal one can have several causes. One of them is the crosslinking agent involvement in intramolecular cycle formation. The contribution of this reaction grows with the system dilution as well as when the crosslinker units in the chain are close one to the other, i.e. its fraction in the copolymer increases. All this is in good agreement with the observed trend. 

Edwards, S. P. "Polymer Networks, Structural and Mechanical Properties" Chompff, A. J. Newman S. Eds. Plenum Press New York 1971. 

Polymer network structure is important in describing the transport through biomedical membranes [139, 140]. The mechanism of diffusion in membranes may be that of pure diffusion or convective transport depending on the mesh size of the polymer network. With this in mind, polymer membranes are typically divided into three major types described below [141]. 

Recent systematic studies on the relation between network structure and substituents in kraft lignin, steam exploded, have shown that the lignin containing networks can be modified in new ways, cf. e.g. (80). Also the toughening of glassy, structural thermosets can be achieved by incorporating a variety of polyether and rubber-type soft segment components in the polymer network structure. 

Edwards,S.F. The statistical mechanics of rubbers. In ChompfljAJ., Newman,S. (Eds.) Polymer networks, structure, and mechanical properties, pp. 83—110. New York Plenum Press 1971. 

Labana, S. S., Newman, S., Chompff, A. J. Chemical effects on the ultimate properties of polymer networks in the glassy state, pp. 453-477. In Polymer networks, structure and mechanical properties. See Ref. (260). 

Lin, C. J., and Bell, J. P., The Effect of Polymer Network Structure upon the Bond Strength of Epoxy- Aluminum Joints, Journal of Applied Polymer Science, vol. 16, 1972, p. 1721. 

Hypothetical sketches of 3 different polymer network structures are shown in Fig. 51. Model a indicates a network with uniform crosslink density. Model b ... 

Fig. 51. Hypothetical two dimensional sketches of three different polymer network structures...

Figure 5.23. The general strategy (a) and examples (It-c) of hyperbranched polymer network structures featuring a siloxane crosslinkage. Reproduced with permission from Meijer, D. Dvornic, R R. Fall 2005 ACS meeting, Midland, Ml.

Kurisawa M and Yui N. Dual-stimuli-responsive drug release from interpenetrating polymer network-structured hydrogels of gelatin and dextran. J. Control. Rel. 1998 54 191-200. 

R.J. Farris, "The Stress-Strain Behavior of Mechanically Degradable Polymers," In POLYMER NETWORKS STRUCTURAL AND MECHANICAL PROPERTIES, ed. A.J. Chompff and S. Newman, pp. 341-394, Plenum, New York, 1971. 

A novel concept for generating new multifunctional modifiers was developed [26], Hydroxyurethane modifiers (HUMs), which possess a wide range of hydrogen bonds, are embedded in an epoxy polymer network without a direct chemical interaction. Some new hybrid materials obtained by introducing hydroxyalkyl urethane into the polymer network structure, without any additional chemical reactions, are described in the following sections. 

Therefore and as previously developed by Sung et al. (47) and reported by other authors, a three-step imbibation process can be postulated. The hydrophilic sites within the PDMAEMA-/-PCL conetwoiks first attract and bind an amount of water, followed by the formation of a secondary hydration shell of water that is preferentially oriented around the bound water and the polymer network structure. Further absorbed water exists as free or bulk-like water. 

Nicholas A. Peppas, a native of Greece, studied chemical engineeringrat N.T.U., Athens (Dipl. Eng., 1971) and at Massachusetts Institute of Technology, from which he received his Sc.D. in 1973. He joined Purdue University in 1976 where he is currently Professor of Chemical Engineering. He is a member of the editorial boards of Biomaterials and the Journal of Applied Polymer Science. He has coauthored more than 90 publications in his areas of research interest, which include diffusion in polymers, polymer network structures, membrane science, and biointerfacial phenomena. In 1982-83 he will be Zyma Foundation Visiting Professor at the University of Geneva, Switzerland. 

Infrared (IR) spectroscopy is one of the most commonly used techniques for the study and characterization of polymers (Koenig, 1992). The goal of such characterization is to relate the structure of polymers to their performance properties. IR has been used to characterize not only the resulting polymers but also the polymerization processes leading to the production of polymer systems (Scranton et al, 2003). The aim of the following sections is to summarize the use of IR in the characterization of polymer network structure with particular attention paid to intermolecular hydrogen bonding that occurs in such systems. 

Processable PAA/PANI-NF and poly(2-acrylamido-2-methyl propyl-sulfonic acid-acrylic acid)/PANI-NF conducting hydrogels with an interpenetrating polymer network structure have recently been synthesized [456]. 

Dusek K (1971). In ChompfT A (ed) Polymer networks Structural and Mechanical Properties. 

Edwards, S. F. Statistical mechanics of rubber, in Polymer Networks Structural and Mechanical Properties (A. J. Chompff, S. Newman, eds.), Plenum Press, New York 1971... 

A new class of liquid crystal/polymer network composite with very small amounts of polymer network (3 Wt%) is described. These composites are formed by photopolymerization of the monomers in-situ from a solution of monomer dissolved in low-molar-mass liquid crystals. Several techniques have proven useful to characterize these polymer networks. This review describes polymer network structure and its influence on electro-optic behavior of liquid crystals. Structural formation in these composites begins with the phase separation of polymer micronetworks, which aggregate initially by reaction-limited, and then by diffusion-limited modes. The morphology can be manipulated advantageously by controlling the crossover condition between such modes, the order of the monomer solution prior to photopolymerization, and the molecular structure of monomers or comonomers. 

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