Poly crosslinking

Crosslinking poly (2,2-dinitropropyl acrylate) in plastic-bonded explosives , US At Energy Comm, UCRL-50434 (1968) CA 70, 39419 (1969)... 

The term IPN was first used in 1960 to describe the apparently homogeneous product obtained from styrene crosslinked with divinylbenzene. IPNs were prepared from this system by taking a crosslinked poly(styrene) network and allowing it to absorb a controlled amount of styrene and a 50% divinylbenzene-toluene solution containing initiator. Polymerisation of this latter component led to the formation of an IPN, the density of which was... 

Allcock, H. R., and Kwon, S., An ionically-crosslinkable poly-phosphazene Poly[di(carboxylatophenoxy)phosphazene] and its hydrogels and membranes. Macromolecules. 22. 75, 1989. 

The design of bioeompatible (blood compatible) potentiometric ion sensors was described in this chapter. Sensing membranes fabricated by crosslinked poly(dimethylsiloxane) (silicone rubber) and sol gel-derived materials are excellent for potentiometric ion sensors. Their sensor membrane properties are comparable to conventional plasticized-PVC membranes, and their thrombogenic properties are superior to the PVC-based membranes. Specifically, membranes modified chemically by neutral carriers and anion excluders are very promising, because the toxicity is alleviated drastically. The sensor properties are still excellent in spite of the chemical bonding of neutral carriers on membranes. 

When the five mol percent crosslinked poly(acrylic acid) release curve was compared (Figure 5) to that for a very lightly crosslinked (less than one percent)... 

Figure 5. Release of insulin from lightly crosslinked (Polycarbophil) and 5 mol% crosslinked poly(acrylic acid).

BD Ratner, IF Miller. Transport through crosslinked poly(2-hydroxyethyl methacrylate) hydrogel membranes. J Biomed Mater Res 7 353-367, 1973. 

YH Bae, T Okano, SW Kim. Temperature dependence of swelling of crosslinked poly(N,N-alkyl substituted acrylamides) in water. J Polym Sci B 28 923-936, 1990. 

The ubiquitous hydrosilation reaction, popular especially in silicone manufacturing,132 has been utilized by Houser and Keller for the synthesis of the networked polymers (104) (Fig. 64) from the reaction of the l,7-bis(vinyltetramethyldisiloxyl)-w-carborane monomer with the polymeric crosslinker, poly(methylhydrosiloxane).133 The reactions were catalyzed by the Speier s catalyst, H2PtCl6. Three samples were... 

Biodegradable Rubbers from Crosslinked Poly(HAMCL). 284... 

Fig. 8. Gel formation of peroxide crosslinked poly(HAMCL), based on coconut fatty acids (COFA), oleic acid (OA), tall oil fatty acids (TOFA) or linseed oil fatty acids (LOFA)...

Figure 1. Polymer synthesis scheme for crosslinked poly anhydrides.

Figure 2. Structure of diacid molecules that can be functionalized to create crosslinked poly anhydride networks.

Canali et al.17 reported the use a linear poly(tartrate) ligand in the asymmetric epoxidation of allylic alcohols. Moderate results were obtained. They also reported the use of branched/crosslinked poly(tartrate), which gave moderate to good results in the asymmetric epoxidation of allylic alcohols. As shown in Scheme 4-9, when L-(+)-tartaric acid and 1,8-octanediol are heated... 

Novel hydrophilic polymer membranes based on crosslinked poly(allylamine hydrochloride) (PAA.HCl)-PVA have been developed in order to dehydrate different organic compounds by pervaporation [33], The characteristics of the acetone dehydration process,... 

Several examples of the binding of enzymes to poly(vinyl alcohol) are in the literature. These could possibly be used to treat enzyme deficiency diseases. In a recent example, trypsin was immobilized on poly(vinyl alcohol) fibers using maleic dialdehyde or bromal. While the reaction was more complete with bromal, the reaction with maleic dialdehyde gave a better support which showed decreasing activity with increasing enzyme content. The activity of the bromal activated system was independant of the enzyme content (52 ). Trypsin and papain were attached to poly(vinyl alcohol) by the reaction sequence shown in Equation 13. In this case, the crosslinked poly(vinyl alcohol) is treated by the 1,3-dioxalone derivative and then converted to either the isothiocyanate or the diazonium salt for coupling with the enzyme. The bound enzymes showed significant, altho reduced, activity in each case (53). 

Reactions with Isocyanates. The reaction of alcohols with isocyanates to form carbamates is well known and similar reactions with poly(vinyl alcohol) would be expected. Until recently, the only available reaction conditions were to use a heterogeneous reaction mixture or to run the reaction in a poor solvent for poly(vinyl alcohol). The best poly(vinyl alcohol) solvents, water and formaide derivatives, react rapidly with isocyanates. Nevertheless, several such reactions have been run in the past and we will cite only a few of them. A potentially photosensitive polymer was made by the reaction of allyl isocyanate with poly(vinyl alcohol) (57) and several workers have crosslinked poly(vinyl alcohol) with hexamethylene diisocyanate (58.59). 

Figure 10.8 Stress-strain curves for 6% crosslinked poly(n-butyl acrylate) elastomer for the sample and control specimen (strain rate= lOOmm/min, room temperature). Adapted from Kushner et al. (2007). Copyright 2007 American Chemical Society.

Fig. 7 Maltotetraose hybrids with various carriers resulting in different chain architectures A poly(ethylene oxide) Ba and Bb poly(acrylic acid), amylose, cellulose, and other polysaccharides Ca cyclodextrin and multifunctional acids Cb amylopectin D crosslinked poly(acryl amide) [156] - Reproduced by permission of Wiley...

Crosslinked poly(styrene) beads (20) were prepared with contain Ru(bpy)2+ anchored at oligo(oxyethylene) spacer group 50). Vigorous stirring was needed for the suspended complex (20) to sensitize the photoreduction of MV2+ in the presence of... 

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