Aliphatic chains, flexible

The Ts of the polymers were in the range 122—250°C, which showed a predictable increase with a decrease in length of the flexible aliphatic chains. 

The polymer structure bears a clear resemblance to that of the polycarbonate of bis-phenol A and of the polysulphones so that there are a number of similarities between the materials. The greatest difference arises from the substantial aliphatic segment, which enhances chain flexibility and hence leads to comparatively low softening points. This has placed severe restrictions on the value of these materials and they have found difficulty in competing with the more successful polycarbonates. 

The use of ordered supramolecular assemblies, such as micelles, monolayers, vesicles, inverted micelles, and lyotropic liquid crystalline systems, allows for the controlled nucleation of inorganic materials on molecular templates with well-defined structure and surface chemistry. Poly(propyleneimine) dendrimers modified with long aliphatic chains are a new class of amphiphiles which display a variety of aggregation states due to their conformational flexibility [38]. In the presence of octadecylamine, poly(propyleneimine) dendrimers modified with long alkyl chains self-assemble to form remarkably rigid and well-defined aggregates. When the aggregate dispersion was injected into a supersaturated... 

In some cases, it is desirable to add a spacer which elongates the stopcock molecule so that the length of the tail can be controlled. This can be a tool to improve the solubility of the whole molecule. Polar groups might help to bind the molecules more strongly inside of the zeolite channels. Spacers which are sufficiently flexible so that they can bend the tail into the zeolite channels include, for example, aliphatic chains, polyethers, or amides. 

Effect of Plasticizer Shape. Extended plasticizer molecules such as aliphatic chains with a high degree of flexibility, usually lower Tg or Tc much more than bulky plasticizer molecules, such as those containing ring structures. However, Table XIII shows that the comparison between aliphatic and aromatic ester plasticizers is also determined by the length of the alcohol residues and by separation between the ester groups. 

These ligands, as exemplified by (12 Figure 2), were first reported by Zinke and Ziegler.31 Synthetic design has since then been modified and improved.64,65 133"135 The attachment of an aliphatic chain bridging two opposite para positions in the calix[4]arenes (i.e. those composed of four phenol groups) has been used to fix the cone conformation in these somewhat flexible molecules.136... 

The effect of chain flexibility is also evidenced by replacing aromatic hardeners by aliphatic ones. This produces an increase in the fracture resistance at room temperature (Kinloch and Young, 1983). 

The aliphatic chain contributes lower viscosity to the adhesive formulation and greater flexibility in the cured state. The reaction of these materials when used alone is very sluggish at room temperature. However, the reaction proceeds at a practical rate by the addition of a base, which acts as an accelerator. Tertiary amines, such as DMP-10 or 30, triethylenete-tramine (TETA), and diethylenetriamine (DETA) are commonly used for this application. 

Mixed aliphatic / aromatic chain (flexible with rigid elements) (13.5) (21.5) (30) (51)... 

The largest-volume polyether used is obtained from propylene oxide polymerized under basic conditions. Polyester polyols are produced from a number of different materials involving diacids and diols to give the ester linkage. Aliphatic polyesters generally are used for elastomers to impart chain flexibility. 

Anhydride (-C-C(0)-0-C(0)-C-) Amide (-NH-C(O)-) SUoxane (-R3Si-0-) Chain flexibility, water sensitive (especially for short aliphatic chains) Chain rigidity, crystalline, water sensitive Chain flexibility and low Tg (especially for small substituents), stable toward oxidation, acid/base reactive... 

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