Polymers chemical linkages

It has been well established that wear resistance of filled rubber is essentially determined by filler loading, filler morphology, and polymer-filler interaction. For fillers having similar morphologies, an increase in polymer-filler interaction, either through enhancement of physical adsorption of polymer chains on the filler surface, or via creation of chemical linkages between filler and polymer, is crucial to the enhancement of wear resistance. In addition, filler dispersion is also essential as it is directly related to the contact area of polymer with filler, hence polymer-filler interaction. 

Polyamides, polyethers is based on the common chemical linkages found in these polymers. Classification Based on the Mode of Synthesis of Polymers... 

A few of the many chemical linkages or groups that can be detected in polymer spectra, along with the approximate wavelengths at which they occur are shown in figure below. The infrared absorption bands of interest in common polymers are... 

FIGURE 1.3 Schematic representation of the silanization procedure of borosilicate or fused silica capillary column inner walls, (a) Surface etching under alkaline conditions, (b) attachment of reactive groups by condensation with silanol, (c) chemical linkage of polymer (PS/DVB considered as example) by free radical polymerization. 

Free space inside the polymer clusters, arising after chemical linkage of microglobules in solution... 

Space between the polymer clusters that build the scaffold by chemical linkage at late stages of polymerization... 

The rate of reversion, or hydrolytic instability, depends on the chemical structure of the base polymer, its degree of crosslinking, and the permeability of the adhesive or sealant. Certain chemical linkages such as ester, urethane, amide, and urea can be hydrolyzed. The rate of attack is fastest for ester-based linkages. Ester linkages are present in certain types of polyurethanes and anhydride cured epoxies. Generally, amine cured epoxies offer better hydrolytic stability than anhydride cured types. 

The surface wettability by water drops has been clearly linked with the concentration of chemically bound nitrogen in the surface. Conversely, measurements of advancing and receding contact angles for water can provide information regarding surface composition. On the other hand, there appears to be little or no direct correlation between water wettability and adhesive strength of evaporated aluminum films. Substantial improvement in adhesion of Ai to many polymers can be achieved by 02 plasma treatment of the polymer surface before metallization. Other workers have shown this to result in chemical linkages between the metal and polymer surface moieties. 

In order to achieve chemical linkage between a soluble metal complex catalyst and an organic polymer, a suitable functionality, forming covalent bonds, has to be introduced into the original polymer. Exceptions whereby an unmodified polymer is directly applied to anchor a homogeneous catalyst [29, 30], e. g., polybutadiene to anchor iron pentacarbonyl [31 ] (eq. (1)), are known, but lack of universal applicability. 

Our research interest in this field is based on the perception that these dendritic polymers could be useful as polymer-rheology control agents as well as spherical, multifunctional macromonomers. Hyperbranched polymers, which were not only thermally and chemically robust under the conditions used, but also could be economically obtained, were created to evaluate these concepts. The latter requirement led us to pursue the one-step polymerization of AB -type monomers. We will review mostly the synthesis of aromatic polymers with stable chemical linkages prepared by the single-step direct method, and we will briefly compare them with polymers made by more controlled multistep syntheses. 

Design of polymer-bound fungicides can accommodate a slow release mechanism or a permanently attached biocide. The chemical linkages used to attach fungicides to polymers could either be hydrolyzable or nonhydrolyzable depending on the type chemical... 

These results demonstrate the chemical linkage between TPEV and PA-6 by graft polymer formation during the reactive extrusion process (Fig. 5). 

Reactive group Chemical linkage points on monomers or prepolymers enabling the formation of polymers via chemical reactions, for example, epoxy or amine groups in the case of epoxy resin adhesives. 

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