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Calorimetry, DSC

The crystal stmcture of glycerides may be unambiguously determined by x-ray diffraction of powdered samples. However, the dynamic crystallization may also be readily studied by differential scanning calorimetry (dsc). Crystallization, remelting, and recrystallization to a more stable form may be observed when Hquid fat is solidified at a carefully controlled rate ia the iastmment. Enthalpy values and melting poiats for the various crystal forms are shown ia Table 3 (52). [Pg.130]

The process known as transimidization has been employed to functionalize polyimide oligomers, which were subsequentiy used to produce polyimide—titania hybrids (59). This technique resulted in the successhil synthesis of transparent hybrids composed of 18, 37, and 54% titania. The effect of metal alkoxide quantity, as well as the oligomer molecular weight and cure temperature, were evaluated using differential scanning calorimetry (dsc), thermogravimetric analysis (tga) and saxs. [Pg.330]

Most hydrocarbon resins are composed of a mixture of monomers and are rather difficult to hiUy characterize on a molecular level. The characteristics of resins are typically defined by physical properties such as softening point, color, molecular weight, melt viscosity, and solubiHty parameter. These properties predict performance characteristics and are essential in designing resins for specific appHcations. Actual characterization techniques used to define the broad molecular properties of hydrocarbon resins are Fourier transform infrared spectroscopy (ftir), nuclear magnetic resonance spectroscopy (nmr), and differential scanning calorimetry (dsc). [Pg.350]

The compositional distribution of ethylene copolymers represents relative contributions of macromolecules with different comonomer contents to a given resin. Compositional distributions of PE resins, however, are measured either by temperature-rising elution fractionation (tref) or, semiquantitatively, by differential scanning calorimetry (dsc). Table 2 shows some correlations between the commercially used PE characterization parameters and the stmctural properties of ethylene polymers used in polymer chemistry. [Pg.368]

The cure of novolaks with hexa has been studied with differential scanning calorimetry (dsc) and torsional braid analysis (tba) (46) both a high ortho novolak and a conventional acid-cataly2ed system were included. The dsc showed an exothermic peak indicating a novolak—hexa reaction ca 20°C higher than the gelation peak observed in tba. Activation energies were also calculated. [Pg.299]

Temperature-risiag elution fractionation (tref) is a technique for obtaining fractions based on short-chain branch content versus molecular weight (96). On account of the more than four days of sample preparation required, stepwise isothermal segregation (97) and solvated thermal analysis fractionation (98) techniques usiag variatioas of differeatial scanning calorimetry (dsc) techniques have been developed. [Pg.149]

Thermal analysis iavolves techniques ia which a physical property of a material is measured agaiast temperature at the same time the material is exposed to a coatroUed temperature program. A wide range of thermal analysis techniques have been developed siace the commercial development of automated thermal equipment as Hsted ia Table 1. Of these the best known and most often used for polymers are thermogravimetry (tg), differential thermal analysis (dta), differential scanning calorimetry (dsc), and dynamic mechanical analysis (dma). [Pg.149]

Transitions such as T and are rapidly and conveniently studied using differential scanning calorimetry (dsc). This technique monitors changes in... [Pg.434]

The glass-tiansition tempeiatuiesfoi solution-polymeiized SBR as well as ESBR aie loutinely determined by nuclear magnetic resonance (nmr), differential thermal analysis (dta), or differential scanning calorimetry (dsc). [Pg.493]

From differential scanning calorimetry (dsc) data from Technochemie GmbH—Verfahrenstechnik. Heating rate = 10° C/min ... [Pg.24]

Uijferential Scanning Calorimetry (DSC) Sample and inert reference materials are heated in such a way that the temperatures are always equal. If an exothermic reaction occurs in the sample, the sample heater requires less energy than the reference heater to maintain equal temperatures. If an endothermic reaction occurs, the sample heater requires more energy input than the reference heater. [Pg.2312]

Differential scanning calorimetry (DSC) Onset temperature of exotherms, heat of reaction... [Pg.24]

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... [Pg.25]

Difl erential thermal analysis (DTA) and differential scanning calorimetry (DSC) are the other mainline thermal techniques. These are methods to identify temperatures at which specific heat changes suddenly or a latent heat is evolved or absorbed by the specimen. DTA is an early technique, invented by Le Chatelier in France in 1887 and improved at the turn of the century by Roberts-Austen (Section 4.2.2). A... [Pg.241]

The solid-liquid transition temperatures of ionic liquids can (ideally) be below ambient and as low as -100 °C. The most efficient method for measuring the transition temperatures is differential scanning calorimetry (DSC). Other methods that have been used include cold-stage polarizing microscopy, NMR, and X-ray scattering. [Pg.43]

In general, X-ray data are used in conjunction with other techniques to obtain as full a picture as possible. For liquid-crystalline materials, differential scanning calorimetry (DSC) and polarizing optical microscopy (POM) are conventionally used. [Pg.139]

Differential scanning calorimetry (DSC) is fast, sensitive, simple, and only needs a small amount of a sample, therefore it is widely used to analyze the system. For example, a polyester-based TPU, 892024TPU, made in our lab, was blended with a commercial PVC resin in different ratios. The glass transition temperature (Tg) values of these systems were determined by DSC and the results are shown in Table 1. [Pg.138]

The SCB distribution (SCBD) has been extensively studied by fractionation based on compositional difference as well as molecular size. The analysis by cross fractionation, which involves stepwise separation of the molecules on the basis of composition and molecular size, has provided information of inter- and intramolecular SCBD in much detail. The temperature-rising elution fractionation (TREE) method, which separates polymer molecules according to their composition, has been used for HP LDPE it has been found that SCB composition is more or less uniform [24,25]. It can be observed from the appearance of only one melt endotherm peak in the analysis by differential scanning calorimetry (DSC) (Fig. 1) [26]. Wild et al. [27] reported that HP LDPE prepared by tubular reactor exhibits broader SCBD than that prepared by an autoclave reactor. The SCBD can also be varied by changing the polymerization conditions. From the cross fractionation of commercial HP LDPE samples, it has been found that low-MW species generally have more SCBs [13,24]. [Pg.278]

The various terms appearing in these equations are self-evident. The differential heat release, dkidt, data are computed from differential scanning calorimetry (DSC). A typical DSC isotherm for a polyurethane reactive system appears in Fig. 11. Energetic composite processing is normally conducted under isothermal conditions so that Eq. (15) is more applicable. [Pg.714]


See other pages where Calorimetry, DSC is mentioned: [Pg.393]    [Pg.431]    [Pg.332]    [Pg.329]    [Pg.44]    [Pg.390]    [Pg.403]    [Pg.149]    [Pg.150]    [Pg.298]    [Pg.368]    [Pg.445]    [Pg.60]    [Pg.260]    [Pg.340]    [Pg.317]    [Pg.318]    [Pg.258]    [Pg.187]    [Pg.233]    [Pg.531]    [Pg.161]    [Pg.242]    [Pg.915]    [Pg.936]    [Pg.496]    [Pg.771]    [Pg.418]   
See also in sourсe #XX -- [ Pg.155 ]




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DSC—See Differential scanning calorimetry

Differential Scanning Calorimetry (DSC) Analysis

Differential Scanning Calorimetry (DSC) Technique

Differential Scanning Calorimetry DSC tracings

Differential scanning calorimetry DSC) experiments

Differential scanning calorimetry DSC) results

Differential scanning calorimetry power compensation DSC

Differential scanning calorimetry, DSC

Dynamic Scanning Calorimetry (DSC)

No Cure - Differential Scanning Calorimetry (DSC)

Power compensation DSCs Differential scanning calorimetry

Scanning Calorimetry (DSC)

Thermal Analysis (DTA) and Differential Scanning Calorimetry (DSC)

Thermal Behaviour Studies by DSC (Differential Scanning Calorimetry)

Thermal Properties DSC (Differential Scanning Calorimetry)

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