Polymers that contain

HydrophobicaHy Modified, Ethoxylated Urethane. HEUR associative thickeners are in effect poly(oxyethylene) polymers that contain terminal hydrophobe units (66). They can be synthesized via esterification with monoacids, tosylation reactions, or direct reaction with monoisocyanates. There are problems associated with aH of the methods of synthesis. The general commercial procedure for their synthesis is by a step-growth addition of... 

Solution Properties. Typically, if a polymer is soluble ia a solvent, it is soluble ia all proportions. As solvent evaporates from the solution, no phase separation or precipitation occurs. The solution viscosity iacreases continually until a coherent film is formed. The film is held together by molecular entanglements and secondary bonding forces. The solubiUty of the acrylate polymers is affected by the nature of the side group. Polymers that contain short side chaias are relatively polar and are soluble ia polar solvents such as ketones, esters, or ether alcohols. As the side chaia iacreases ia length the polymers are less polar and dissolve ia relatively nonpolar solvents, such as aromatic or aUphatic hydrocarbons. 

In addition to the commercial aromatic polyamides described above many others have been prepared but these have not achieved commercial viability. There are, however, a number of other commercial polymers that contain amide groups such as the polyamide-imides. The latter materials are discussed in Section 18.14. 

Silicone acrylates (Fig. 5) are again lower molecular weight base polymers that contain multiple functional groups. As in epoxy systems, the ratio of PDMS to functional material governs properties of release, anchorage, transfer, cure speed, etc. Radiation induced radical cure can be initiated with either exposure of photo initiators and sensitizers to UV light [22,46,71 ] or by electron beam irradiation of the sample. 

The refractive index detector, in general, is a choice of last resort and is used for those applications where, for one reason or another, all other detectors are inappropriate or impractical. However, the detector has one particular area of application for which it is unique and that is in the separation and analysis of polymers. In general, for those polymers that contain more than six monomer units, the refractive index is directly proportional to the concentration of the polymer and is practically independent of the molecular weight. Thus, a quantitative analysis of a polymer mixture can be obtained by the simple normalization of the peak areas in the chromatogram, there being no need for the use of individual response factors. Some typical specifications for the refractive index detector are as follows ... 

One useful drug delivery system is derived from polymers that contain acid-labile linkages in their backbones because hydrolysis rates of such polymers can be readily manipulated by means of acidic or basic excipients physically incorporated into the matrix (2). Further, under certain conditions the hydrolysis of such polymers can be... 

The steric bulk of steroid structures prevents their use as the only organic side group present. However, mixed-substituent polymers that contain both steroidal side groups and amino acid ester or other cosubstituent units can be readily synthesized. If a saturated A ring is present in the steroid, linkage to the polymer chain is complicated by side reactions that result from dehydration of the steroid (chlorophosphazenes are powerful dehydrating agents). 

Polymers that contain amide linkage groups are called polyamides. Proteins, which are biological polyamides, are described in Section 13-1. Here we focus on two commercially important polyamides Nylon 66 and Kevlar. 

Macromolecular drugs, in general, can be divided into four types (a) polymeric drugs—these represent macromolecules that themselves display pharmacological activity, and polymers that contain therapeutically active groups as an integral part of the main chain ... 

In practice, there is no such thing as a pure isotactic or syndiotactic polymer. Once again, we find that polymers comprise a statistical distribution of chemical structures. Polymers that contain steric centers inevitably incorporate a certain number of steric defects that prevent us from obtaining 100% isotacticity or syndiotacticity. Polymer manufacturers vary the catalyst type and reaction conditions to control the tacticity level and the resulting properties. 

Atoms have different abilities to form bonds depending on their valence shell electrons. Most atoms present in polymers strive to meet an octet, i.e. eight electrons in their valence. (Hydrogen atoms are a very important exception, particularly in the case of polymers that contain more hydrogen atoms than carbon atoms.) To reach this goal, atoms form bonds. 

L Organoboron Polymers that Contain Borazine or 9-BBN with Utility in the Production of High-Performance Fibers... 

There have been no recent examples of polymers that contain the triphosphatriborin ring system. 

Hi. Organoboron Polymers that Contain Polypyrazolylborate or Pyrazabole Ring Systems... 

When (NPC12)3 is heated to 250 °C, polymerization occurs, giving polymers that contain up to 15,000 monomer units. 

The first example of a hybrid polymer that contains both [NS(0)C1] and [NPC12] units, 141a, was obtained as a pale yellow elastomer by ring-opening polymerization (Scheme 10).305 In the presence of GaCl3, this polymerization process proceeds quantitatively at room temperature in CH2Cl2-306... 

Polymers that Contain Te4 Squares Te42+, Te72+ and Te102+... 

Polymers that Contain Te6 Homocycles Te72+ and Te82+... 

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