Physical testing differential scanning calorimetry

Many different test methods can be used to study polymers and their physical changes with temperature. These studies are called thermal analysis. Two important types of thermal analysis are called differential scanning calorimetry (DSC) and differential thermal analysis (DTA). DSC is a technique in which heat flow away from a polymer is measured as a function of temperature or time. In DTA the temperature difference between a reference and a sample is measured as a function of temperature or time. A typical DTA curve easily shows both Tg and T . 

Differential scanning calorimetry can be used to detect isosorbide dinitrate in the presence of various proportions of other isohexide mononitrates in pharmaceutical formulations81 and for testing its hazardous characteristics.82 A complete analytical profile for isosorbide dinitrate, detailing spectroscopic and other physical properties, as well as useful analytical methods, has been reported.83... 

I) Physical characteristics of the oil condition monitoring wear metals analysis, fuel contamination, viscosity, chromatography, flash point, water content, insoluble test, blotter test, direct reading ferrography, differential scanning calorimetry and colorimetry. 

Provisional specifications have been created for all packaging components, and these are subsequently used to clear all materials through a QC plus type operation prior to use in any tests, irrespective of whether these are feasibility or formal stability studies. Procedures should include (for plastics) material identification (by IR, UV, differential scanning calorimetry (DSC), etc.), physical assessment including dimensions and functional tests, and should be of greater technical and scientific depth than the QC procedures used for subsequent regular incoming production materials (hence the use of the phrase QC plus ). 

This research note focuses on process characteristics of pol5nner solutions, such as viscosity and electrical conductivity, as well as the parameters of electrospinning using poly-3-hydroxybutyrate modified by titanium dioxide nanoparticles, which have been optimized. The structure of materials has been examined by means of X-ray diffraction, differential scanning calorimetry, IR-spectroscopy, and physical-mechanical testing. 

Thermal analytical techniques such as thermo-gravimetric analysis (TGA) and differential scanning calorimetry (DSC) permit assessment of polymers without involved physical testing. In TGA, the weight change is monitored while the temperature is increased at a constant rate. In DSC, the temperature is increased at a constant rate and the amount of heat necessary to maintain a temperature change at a constant rate is measured. Isothermal varieties of these techniques are used where the temperature is held constant and changes noted. 

Differential scanning calorimetry and Fourier transform infrared spectroscopy techniques were used to study the structure of water molecules in polyvinyl alcohol and polyethylene grafted acrylate hydrophilic polymers. Varying amounts of water were added to test samples and the samples conditioned to the sorption equilibrium state in sealed containers for 24 hours prior to evaluation. It was concluded that below a threshold water content, depending on the polymers physical and chemical stmcture, water molecules absorbed in hydrophilic polymer cannot form ice crystals in the polymer matrix. Above this threshold content, the water crystallises but below zero. It was also demonstrated that the absorbed water in hydrophilic polymers develops differing hydrogen bonds in the first and second hydration layers. It was concluded that the potential influence of these intermolecular interactions should therefore be taken into account whenever a polymer is used with a solvent. 25 refs. 

Physical properties were determined by differential scanning calorimetry (dsc) with a Perkin-Elmer DSC-4 instrument and by dynamic mechanical thermal analysis (dmta) using a Polymer Laboratories dmta instrument. Stress-strain tests were performed on an Instron Table Model TM-M at a cross-head speed of 1mm min. The Young s modulus was obtained from the tangent of the initial slope of the force vs. elongation curve. Scanning electron microscopy (s.e.m.) employed an AMR 900 instrument. Specific experimental details are given elsewhere (9,10,11). 

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