Matrix polymer, requirements

Fig. 24. Representative cross-linking systems employed in negative tone CA resists, (a) Epoxy polymers requiring organic solvent development, (b) PHOST-based cross-linking systems requiring aqueous development, (c) Monomeric cross-linking agents used in PHOST matrix polymers.

The matrix polymers can be divided into brittie or ductile categories, each having specific requirements for achieving toughness (Table 3). Numerous variations are possible. For instance, often mbber particles that vary in both size and kind are desirable for optimum performance. In these cases, the requirements of the mbber phase and the toughening mechanisms are complex. 

The second type of polymer, unsaturated polyanhydrides of the structure [-(OOC-CH=CH-CO)x-(OOC-R-CO)y-]n, have the advantage of being able to undergo a secondary polymerization of the double bonds to create a crosslinked matrix. This is important for polymers requiring great strength, for instance. These polymers were prepared from the corresponding diacids polymerized either by... 

Whenever the commercially available particles do not match the operator s requirements, a variety of possibilities exist in order to modify the particles from company suppliers. Similarly to other doped beads the dyes [92] or quantum dots [107, 108] can be physically entrapped into magnetic beads by swelling or are covalently bound to the surface of the particles. If localization of the dye on the particle surface is desired or if the polarity of dye and/or matrix polymer does not allow the irreversible entrapment of the dye in the bulk polymer, a covalent attachment of the dye is preferable [109, 110]. Even the covalent binding of whole fluorescent nanoparticles to magnetic microparticles is possible, as shown by Kinosita and co-workers who investigated the rotation of molecular motors [111]. 

Kinetic models determine the minimum time required to cure the resin (i.e., guarantee sufficient physical and mechanical properties). They also determine the heat of reaction of the resin for use by heat transfer models and the degree of crosslinking for use in viscosity submodels. The exothermic cure reaction for the transformation of the epoxy resin to the cured matrix polymer can be expressed as ... 

With drugs that must be given in high doses, the large quantity of matrix limits the applications of solid solutions considerably, as it is difficult to produce tablets, capsules etc. of normal size. In addition, a large quantity of active substance and polymers requires the use of a large quantity of organic solvent. 

Hydrophilic matrix formulation of high-dose drugs (approximating 1.0g) is challenging because of the overall dosage weight limitations versus the quantity of the polymer required to achieve desired release profiles. It has been reported that very large tablets that are formulated to be swallowed whole (e.g. ER and delayed-release formulations) lead to poor patient compliance and therefore reduced market acceptability [50]. 

Electrically conductive polymer composites were made by dispersing TCNQ salt in polymer matrices. Composite film conductivity and stability are discussed in terms of charge-transfer interaction between TCNQ salt and matrix polymer and the resulting film morphology. The extent of CT interaction and tendency of microcrystallization of TCNQ salt in the matrices were determined by visible spectra. Conductivity and stability are morphology dependent of the film high conductivity requires a uniform, densely packed dispersion of TCNQ salt microcrystallites. The highest conductivity was always attained at [TCNQ°]/[TCNQ ]sl. 

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