Results and Discussion Thermal Analysis

Detailed studies on the influence of an increasing ENR content on the thermal stability of PVC/ENR blends have also been reported. Other evidence vas obtained by Calandrelli and co vorkers [17], who improved the thermal properties of the aromatic polyoxadiazole by blending it with a secondary homopolymer component, polyamide. 

The thermal degradation of blends based on PVC, PMMA and PS was also monitored [4]. Recent studies of PMMA systems by Ramesh and coworkers showed that the low thermal resistance of PMMA was suppressed when it was blended with PVC [18], and suggested that the PMMA/PVC blend matrix is more heat-stable than a matrix formed by the PMMA homopolymer alone. 

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An explanation for the organization of the composite components units discussed above was found in the results of a thermal analysis. The examples of differential thermogravi-metric (DTG) curves for graphite oxide, HKUST-1 and their composites with various contents of GO are presented in Fig. 10.6. Since no significant weight loss was measured above 450 °C, only the temperature range between 30 °C and 450 °C is shown, even though the analyses were carried out up to 1000 °C. In the case of GO a peak at 100 °C... 

Although differential scanning calorimetry (DSC) is used in many different industries, its application and use in the plastics industry is widely accepted. It is used to characterize materials for melting points, softening points, and other material and material-reaction characteristics such as specific heat, percent crystallinity, and reaction kinetics. This chapter addresses the practical uses of DSC in the plastics industry, focusing on the most common tests and experiments. Advanced analysis will be mentioned briefly, but not reviewed in detail. For the best results and the most reproducible data, consider all of the suggestions about operational variables discussed, and you will experience successful and reliable thermal analysis. 

Thermogravimetric analysis (TGA) is the most widely used thermal analysis technique, although other techniques such as differential scanning calorimetry (DSC) and differential thermal analysis (DTA) have also been used for polymer blends (see Table 8.1). In this section, we will limit our discussion to TGA, as its results (such as onset degradation temperature, degradation rate, and kinetic parameters) are most indicative of the fire performance of materials in fires. 

The thermooxidative stability of NR was studied at 150C as a function of the cure process (sulphur, sulphurless or peroxide curing) and the properties of the carbon black filler (five different carbon blacks were used). The thermooxidation was followed by iodometric analysis of hydroperoxide levels, FTIR spectroscopy and differential thermal analysis. The results were discussed and they showed that the type of curing system had an effect on the degradation profile, but the surface reactivity and structure of the carbon black had a controlling role in each system. 13 refs. 

Rietveld (g.c.) analysis of the neutron diffraction data on isotactic polypropylene is still in progress. It has afforded the interesting result, already discussed, that the profiles are better approximated by Cauchy than by Gaussian functions. The structural analysis is now restricted to the fourth model (P2 /c, Immirzi), which gives an excellent agreement between observation and calculation, but with the fraction of reversed helices close to 50% instead of 25% and with less chain symmetry. The other models will be tested for a more complete comparison with x-ray results. We cannot exclude, however, the possibility that the two samples used, which have different chemical, thermal and mechanical history, can really have different structures. 

L.L. Bircumshaw, B.K Newman "The Thermal Decomposition of Ammonium Perchlorate I. Introduction, Experimental, Analysis of Gaseous Products and Thermal Decomposition Experiments," Proc. Roy. Soc. (London) A227 (1954) 115-132 ibid, "The Thermal Decomposition of Ammonium Perchlorate II. The Kinetics of the Decomposition, the Effect of Particle Size, and Discussion of Results" A227 (1955) 228-241. L.L.Bircumshaw, T.R. Phillips, "The Kinetics of the Thermal Decomposition of Ammonium Perchlorate" J. Chem. Soc. 122 (1957) 4741-4747. 

UV light induced grafting onto wood cellulose is reported for several vinyl monomers. The reaction is initiated by free radical initiators such as phenylace-tophenone and benzophenone derivatives. Percent grafting-time conversion curves are determined as a function of the initiators, monomers, pulps and additives. Additional typical results obtained in IR spectroscopy, GPC and thermal analysis are reported. A discussion about the use of a photochemical procedure in obtaining cellulose graft copolymers is presented. 

The pure components, as well as IPNs produced at various ratios, were characterized by density measurements, dynamic thermal mechanical analysis, and electron microscopy. Results are presented and discussed below. 

The subhalides of tellurium are an especially important class of solid state compounds, and they have been the subject of intensive studies, so that a rather complete picture of their chemistry and their properties has been obtained in recent years. Because of their high tellurium content they contain fragments of the homonuclear tellurium chains their modified tellurium structures are of great current interest with respect to possibly significant physical properties. Consequently, the results of various investigations on the synthesis of the compounds, on phase analysis by thermal methods, on crystal growth, on the structures, on spectroscopic, thermodynamic, optical, photoelectric, electrochemical properties have been reported in the last two decades. In a comprehensive review (237) all significant results are reported and discussed in detail so that the present chapter will be restricted to some selected and chemically important features. 

This book contains papers from the Fourth International Conference on Computational Methods and Experiments in Materials Characterisation which brought researchers who use computational methods, those who perform experiments, and of course those who do both, in all areas of materials characterisation, to discuss their recent results and ideas, in order to foster the multidisciplinary approach that has become necessary for the study of complex phenomena. The papers in the book cover the follow topics Advances in Composites Ceramics and Advanced Materials Alloys Cements Biomaterials Thin Films and Coatings Imaging and Image Analysis Thermal Analysis New Methods Surface Chemistry Nano Materials Damage Mechanics Fatigue and Fracture Innovative Computational Techniques Computational Models and Experiments Mechanical Characterisation and Testing. 

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