Differential scanning calorimetry solvents

What are the consequences What is the maximum pressure Vapor pressure of solvent as a function of temperature Gas evolution Differential Thermal Analysis (DTA) / Differential Scanning Calorimetry (DSC) Dewar flask experiments... 

Common examples of the high Tg macromers are based on polystyrene or polymethylmethacrylate (PMMA) polymers of sufficiently high molecular weight to have a high T (typically on the order of 70-100°C as measured by differential scanning calorimetry) and also to make them immiscible with the acrylic polymer backbone once the solvent or heat has been removed. Typical molecular weight of the polystyrene or PMMA macromers is on the order of 5000-10,000 Da. Their generic structure can be pictured as in Fig. 13 (shown there for polystyrene). 

Table II. Selective Solvent Extraction, Calculated Mc PDMAAm, and Differential Scanning Calorimetry Data...

Brittle colorless films of PBPP may be cast from tetrahydrofuran solution. The insoluble portion of PBPP is swelled by the tetrahydrofuran and gives rise to free-standing films on solvent evaporation. Differential scanning calorimetry experiments on PBPP show a glass transition temperature at 40 °C, and some indication of a melting transition at 170° C. 

Birefringence measurements have been shown to be very sensitive to bimodality, and have therefore also been used to characterize non-Gaussian effects resulting from it in PDMS bimodal elastomers [5,123]. The freezing points of solvents absorbed into bimodal networks are also of interest since solvent molecules constrained to small volumes form only relatively small crystallites upon crystallization, and therefore exhibit lower crystallization temperatures [124—126]. Some differential scanning calorimetry (DSC) measurements on... 

Apart from the qualitative observations made previously about suitable solvents for study, the subject of solvates has two important bearings on the topics of thermochemistry which form the main body of this review. The first is that measured solubilities relate to the appropriate hydrate in equilibrium with the saturated solution, rather than to the anhydrous halide. Obviously, therefore, any estimate of enthalpy of solution from temperature dependence of solubility will refer to the appropriate solvate. The second area of relevance is to halide-solvent bonding strengths. These may be gauged to some extent from differential thermal analysis (DTA), thermogravimetric analysis (TGA), and differential scanning calorimetry (DSC) solvates of "aprotic solvents such as pyridine, tetrahydrofuran, and acetonitrile will give clearer pictures here than solvates of "protic solvents such as water or alcohols. 

Bisphthalonitrile monomers were cured neat, with nucleophilic and redox co-reactants, or in combination with a reactive diluent. Dynamic mechanical measurements on the resulting polymers from -150 to +300°C turn up several differences attributable to differences in network structure. Rheovibron results were supplemented with solvent extraction, differential scanning calorimetry (DSC), vapor pressure osmometry, and infrared spectroscopy to characterize the state of cure. 

Solvent effects including 2-methyl-l,3-dioxepane (MDOP), as a solvent, on the propagation kinetics of methyl acrylate (MMA) have been investigated using the PLP-SEC technique (PLP = pulse laser polymerization) <2005MI267>, and the composition of dioxolane-dioxepane copolymers has been studied by IR and differential scanning calorimetry (DSC) <2004PB349>. 

Of course, not all methods of cocrystal production require the use of auxiliary solvents. Thermal microscopy was used to determine if a particular carboxylic acid could cocrystallize with 2-[4-(4-chloro-2-fluorophe-noxy)phenyl]pyrimidine-4-carboxamide, with positive interactions being detected as crystalline material being produced at the binary interface [35]. Once identified, authentic cocrystal systems were prepared on a larger scale using solution-phase methods. In a similar study, hot-state microscopy was used to screen the possible interactions of nicotinamide with seven compounds of pharmaceutical interest that contained carboxylic acid groups [36]. A screening method for cocrystal formation based on differential scanning calorimetry has also been described, and used to demonstrate cocrystal formation in 16 out of 20 tested binary systems [37],... 

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