Semi-IPNs polymer networks

In their further studies on chitosan for biomedical applications, Lee et al. [133] reported a procedure for preparing semi-IPN polymer network hydrogels composed of (3-chitosan and PEG diacrylate macromer, by following a similar procedure to that discussed above. The crystallinity as well as thermal and mechanical properties of gels were reported [133]. Reports on the drug release behavior of the gels are not available. 

With controllable strength of the self- and hetero-associated hydrogen, a molecular level penetrated semi-interpenetrating polymer networks (semi-IPNs) of ST-VPDMS with poly(N-vinylpyrrolidone) (PVPr) were prepared by condensation of the self-associated silanols.13... 

Semi-interpenetrating Polymer Network (Semi-IPN) Synthesis ... 

An increase in heat deflection temperature of some thermoplastic polymers can be achieved by the addition of polyfunctional aromatic cyanates (BPA/DC in particular) and trimerization catalysts. A rigid network is formed as a resul t of the cyanate trimerization. The polymer material consists of a linear polymer and a crosslinked network and belongs to the class of semi-IPNs (semi-interpenetrating Polymer Networks) the corresponding classification is given in [34-37]. 

When monomer 2 is swollen into network 1 and polymerized in situ to form a linear polymer, a semi-interpenetrating polymer network (semi-IPN) of the first kind arises (18,19, 20, 21, 22). The first kind denotes that the first polymer synthesized forms the network (Figure 5A). A semi-IPN of the second kind denotes that the first synthesized polymer is linear and the second synthesized polymer is crosslinked (23-25). If polymer 1 is linear and polymer 2 is crosslinked, the structure in Figure 5B arises. In general, polymerizing 2 first and then 1, yields quite... 

Semi-Interpenetrating Polymer Network (SIPN) A semi-interpenetrating polymer network (SPIN) is a combination of two or more crosslinked polymers with two or more linear or branched polymers, at least one of which was synthesized and/or crosslinked in the presence of the others. An SIPN is distinguished from an IPN because the constituent linear or branched macromolecules can, in principle, be separated from the constituent polymer network(s) without breaking chemical bonds it is a polymer blend [7]. 

Semi-interpenetrating polymer networks (semi-IPN, also called pseudo-IPN)... 

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. 

Interpenetrating/Semi-Interpenetrating Polymer Network (IPN/SIPN)... 

Figure 2.10 Six basic modes of linking two or more polymers are identified (20). (a) A polymer blend, constituted by a mixture or mutual solution of two or more polymers, not chemically bonded together, (b) A graft copolymer, constituted by a backbone of polymer I with covalently bonded side chains of polymer II. (c) A block copolymer, constituted by linking two polymers end on end by covalent bonds, (d) A semi-interpenetrating polymer network constituted by an entangled combination of two polymers, one of which is cross-linked, that are not bonded to each other, (e) An interpenetrating polymer network, abbreviated IPN, is an entangled combination of two cross-linked polymers that are not bonded to each other, (f) AS-cross-linked copolymer, constituted by having the polymer II species linked, at both ends, onto polymer I. The ends may be grafted to different chains or the same chain. The total product is a network composed of two different polymers.

Hao et al. [30] obtained a semi-interpenetrating polymer network (semi-IPN) based on linear PCL (1-PCL) and the PCL network (net-PCL) in which HAp nanocrystals were homogeneously dispersed. The preparation process of semi-IPN (l-PCL/net-PCL)/HAp is shown in Fig. 18. 

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