Differential scanning calorimetry studied using

The use of the Brabender Plasticorder is widespread in the development and quality control of formulations destined to be used in uPVC foam extrusion applications. The morphology transformations associated with the process have been widely studied but the particularities of the application have not often been taken into account - low K-value and high concentration of high molecular weight process aid. This work uses a commercially viable formulation to examine the fusion aspect of the transformation process. Differential scanning calorimetry is used to observe the degree of fusion. 9 refs. 

We have used thermal analysis to study the impact of the tin species on polymer transitional behaviour. Differential Scanning Calorimetry studies shows that the polymer has a glass transition temperature (Tg) at -120°C and a... 

A rather different study of the kinetics of decomposition of solid complexes of [VO(dbm)2(L)] (dbm = dibenzoylmethanato, L = py and several methyl-, dimethyl- and amino-pyridines) used differential scanning calorimetry (DSC). Using the temperature that corresponds to the loss of the molecule L in equation (37), a linear relationship was found between it and the basicity of L, except for 4-amino- and 4-methyl-pyridine. 

Using differential scanning calorimetry, studies on the isothermal bulk polymerization of diallyl fumarate, diallyl maleate, and diallyl succinate were carried out. 

Differential scanning calorimetry is used in this study to examine the crystallization behavior of polypropylene. Crystallization exotherms are analyzed according to the procedure outlined by Gupta et al where the parameters shown in Figure 1 are defined as follows ... 

Figure 2 shows the results of differential scanning calorimetry studies of these polymers. The glass transition temperature of the polybutadiene resin, R-45HT, is about -75 C. The glass transition temperature increases as the percentage of excess TDI used to make the polyurethane... 

Differential scanning calorimetry was used to study the non-isothermal crystallization behavior of blends of poly(phenylene sulfide) (PPS) with the thermotropic liquid-crystalline copoly(ester amide) Vectra-B950 (VB) [126], The PPS crystallization temperature and the crystallization rate coefficient increased significantly when 2-50% VB was added. The Ozawa equation was shown to be valid for neat PPS as well as for the blends. The values of the Avrami exponents matched well against those determined previously using isothermal analysis, and they are independent of the concentration of VB. 

Differential scanning calorimetry studied DSC curves of the plain NFD, MC-g-AAm/G microspheres, and NFD-loaded MC-AAm/G microsphetes were recorded using Rheometric Scientific differential scanning calorimeter (Model-DSC SP, UK). The analysis was performed by heating the samples at the rate of 10 °C/min under inert atmosphere. 

Studies of the thermal and chemical stability of polymers are of paramount importance and instrumentation used in these studies discussed in Chapter 9 include thermogravimetric analysis, differential thermal analysis, differential scanning calorimetry, thermal volatilisation analysis and evolved gas analysis. Monitoring of resin cure is another important parameter in polymer processing in which dynamic mechanical analysis, dielectric thermal analysis and differential scanning calorimetry is used (Chapter 10). 

During the last decade there has been a rapid expansion in the scope of experimental studies on clathrate hydrates. In particular, differential scanning calorimetry studies have been used to obtain direct measurements of thermodynamic properties and accurate measurements of composition [14], and Xe NMR has been used as a direct probe of the environment of the guest molecules [15]. Measurements of the thermal conductivity have also attracted considerable interest [16]. Other related experiments include supersonic beam [6] and thin-film IR [17] studies, which have been used to study some of the processes that might contribute to nucleation of clathrate hydrates. These experiments are beginning to provide the sort of data base that is needed for a fundamental understanding of the behaviour of clathrate hydrates. 

Modulated differential scanning calorimetry was used to study miscible polymer blends. The blends studied... 

Differential scanning calorimetry studies have been ongoing over the past ten years at MMI. The very early work was carried out using a Ferkin-Elmer DSC-IB unit later work has been continued with a DuPont 910 DSC cell in conjunction with either the 990 or 1090 Thermal Analyzer control units. The effects of molecular weight, crosslinking, crystallinity, oxidation, copolymer composition, and tacticity on the strength of the Tu and Tip transitions have been examined. 

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

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]. 

ADMET polymers are easily characterized using common analysis techniques, including nuclear magnetic resonance ( H and 13C NMR), infrared (IR) spectra, elemental analysis, gel permeation chromatography (GPC), vapor pressure osmometry (VPO), membrane osmometry (MO), thermal gravimetric analysis (TGA), and differential scanning calorimetry (DSC). The preparation of poly(l-octenylene) (10) via the metathesis of 1,9-decadiene (9) is an excellent model polymerization to study ADMET, since the monomer is readily available and the polymer is well known.21 The NMR characterization data (Fig. 8.9) for the hydrogenated versions of poly(l-octenylene) illustrate the clean and selective nature of ADMET. 

Rigid polyurethane foams were prepared at room temperature using eommercial polyols and polymerie 4,4 -diphenyl methane diisoeyanate, and used to study their reeyeling by aminolysis. The reaction products obtained by treatment with diethylene triamine at 180 C were evaluated as hardeners for epoxy resins. The exothermie heats of euring were determined over the temperature range 60-80 C by differential scanning calorimetry. A reaction order of 2.2-2.4 was obtained. 8 refs. 

Thermoanalytical techniques such as differential scanning calorimetry (DSC) and thermogravi-metric analysis (TGA) have also been widely used to study rubber oxidation [24—27]. The oxidative stability of mbbers and the effectiveness of various antioxidants can be evaluated with DSC based on the heat change (oxidation exotherm) during oxidation, the activation energy of oxidation, the isothermal induction time, the onset temperamre of oxidation, and the oxidation peak temperature. 

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