Synthetic polymer defined

Polymer-based, synthetic ion-exchangers known as resins are available commercially in gel type or truly porous forms. Gel-type resins are not porous in the usual sense of the word, since their structure depends upon swelhng in the solvent in which they are immersed. Removal of the solvent usually results in a collapse of the three-dimensional structure, and no significant surface area or pore diameter can be defined by the ordinaiy techniques available for truly porous materials. In their swollen state, gel-type resins approximate a true molecular-scale solution. Thus, we can identify an internal porosity p only in terms of the equilibrium uptake of water or other liquid. When crosslinked polymers are used as the support matrix, the internal porosity so defined varies in inverse proportion to the degree of crosslinkiug, with swelhng and therefore porosity typically being more... 

Dendrimer synthesis involves a repetitive building of generations through alternating chemistry steps which approximately double the mass and surface functionality with every generation as discussed earlier [1-4, 18], Random (statistical) hyperbranched polymer synthesis involves the self-condensation of multifunctional monomers, usually in a one-pot single series of covalent formation events [31], Random hyperbranched polymers and dendrimers of comparable molecular mass have the same number of branch points and terminal units, and any application requiring only these two characteristics could be satisfied by either architectural type. Since dendrimer synthesis requires many defined synthetic and process purification steps while hyperbranched synthesis may involve a one-pot synthetic step with no purification, the dendrimers will necessarily be a much more expensive material to produce. 

Sequence-Defined Polymers Allow Synthetically Controlled Functionality. 239... 

In controlled polymer synthesis, in addition, it is particularly important that the control herein implies not only the simple regulation of molecular weights, MWD, and other structural factors but also the precise introduction of functional groups into specific positions of polymers with well-defined architectures. Namely, the control of one or more of these structural factors, then, leads to a variety of polymers of synthetic interest, as some of them illustrated schematically in Fig. 2 ... 

Diffusion of Water Vapor in Newborn Rat Stratum Corneum. Measurement and interpretation of diffusion in heterogenous biological systems such as the stratum corneum are difficult compared with similar measurements for well-defined synthetic polymer systems, but studies of water diflFusion in stratum corneum are essential to a better understanding of those factors which contribute to the barrier function of the corneum. Water diffusion measurements under both equilibrium and non-equilibrium conditions are useful to probe the influence of temperature and other factors on stratum corneum macromolecular structure. 

FIGURE 20.2 Relationships of the most probable (M), number average (Mn), viscosity average (My), weight average (M ), and Z average (M ) molecular weights used to define synthetic polymers. 

Moreover, by combining naturally derived polymers with synthetic building blocks, hybrid materials can be created offering both a defined functionality and biocompatibility as well as a high adaptability in terms of composition and structure. In the production of such hybrid systems, PEG is one of the most commonly used synthetic components since it provides excellent bio-compatibility, a hydrophilic and uncharged character, and the possibility to easily modify its terminal end groups. Some biohybrid hydrogel materials will be presented in Section 5.5. 

The precise integration of oligopeptides (or proteins) into well-defined synthetic polymers results in hybrid... 

The use of chemically defined synthetic polymers is associated with minimal human immune responses. These materials are based on carbon, hydrogen, nitrogen and oxygen which are basic building blocks of the biological system. Thus the generation of antigenic material would be unlikely. Nevertheless, there are some polymeric materials with additional chemical moieties that are of concern. 

The interaction between macromolecules and surfactants in aqueous solution has been extensively investigated for a few decades. First, the protein-surfactant systems were stressed because of their biological importance. With the appearance of well-defined synthetic polymer m< els, the research was extended to the neutral polymer-surfactant systems, too, with the promise of a deeper insight into the more complex protein-surfactant interaction. 

Niu, J., Hili, R., Liu, D.R., 2013. Enzyme-fiee translation of DNA into sequence-defined synthetic polymers structurally unrelated to nucleic acids. Nat. Chem. 5, 282—292. 

Glatzel, S., Badi,N., Pach, M., Laschewsky, A. and Lutz, J.-F. (2010) Well-defined synthetic polymers with a protein-like gelation behavior in water, Chem Commun, 4517 519, doi 10.1039/c0cc00038h. 

A fully defined synthetic polymer, poly(2-[methacryloyloxy]ethyl dimethyl-[3-sul-fopropyl] ammonium hydroxide) (PMEDSAH), was grafted onto TCPS dishes via... 

Olefin fibers, also called polyolefin fibers, are defined as manufactured fibers in which the fiber-forming substance is a synthetic polymer of at least 85 wt % ethylene, propjiene, or other olefin units (1). Several olefin polymers are capable of forming fibers, but only polypropylene [9003-07-0] (PP) and, to a much lesser extent, polyethylene [9002-88-4] (PE) are of practical importance. Olefin polymers are hydrophobic and resistant to most solvents. These properties impart resistance to staining, but cause the polymers to be essentially undyeable in an unmodified form. 

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