Amorphous solid feasibility

Despite the current lack of clarity regarding the relationship between glass transition and chemical reaction kinetics, it is still quite feasible that chemical and biochemical reaction rates may be governed by mobility, i.e., the mobility that is most rate limiting to a particular reaction scheme (e.g., water mobility, reactant mobility, molecular-level matrix mobility, local or microregion mobility), but perhaps not simply by an average amorphous solid mobility as reflected by the Tg. Ludescher et al. (2001) recommend the use of luminescence spectroscopy to investigate how rates of specific chemical and physical processes important in amorphous solid foods are influenced by specific modes of molecular mobility, as well as by molecular structure. 

The most thermodynamically stable polymorph is usually desired for the API product to maximize its formulated stability. Selecting the thermodynamically stable form does however, have the disadvantage of minimizing the solubility and bioavailability. Although less desirable and common it is feasible to use an amorphous solid form of the API if it can be demonstrated that it is stable in the formulation. 

Extension of the correlations to polymers containing other elements, such as inorganic and organometallic polymers [16] containing boron [17,18] or phosphorus [19]. Such an extension appears feasible since the properties of such solids as amorphous selenium, and complicated chalcogenide-based alloys used in electrical and optical applications, can often be calculated by techniques resembling the methods used to study ordinary polymers [20,21]. 

The results presented here illustrate the general feasibility of this technique. They relate primarily to the behavior of thermal and current noise in the glass transition (Tg) or melting (Tm) region of an amorphous (polystyrene) and a crystalline (HD-polyethylene (HDPE)) polymer rendered conductive by the addition of minor amounts of carbon black, and further they relate to the noise of aqueous solutions of certain polymers during Couette flow. Because of experimental diflBculties, noise measurements on solid polymers during deformation and flow have not yet produced useful results. 

Using blends containing PCL, Koleske and Lundberg extended previous studies of polymer blends of wholly amorphous polymers to ones in which one component is crystalline [2]. An inherently crystallisable component may crystallise from a miscible amorphous blend, in a liquid-solid phase separation, and exhibit a melting transition close to that of the homopolymer normally the crystalline material would be a pure single polymer it is feasible that both components of a binary blend may crystallise separately. 

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