Phenolics Thermal analysis

Thermal properties of several chlorinated phenols and derivatives were studied by differential thermal analysis and mass spectrometry and in bulk reactions. Conditions which might facilitate the formation of stable dioxins were emphasized. No two chlorinated phenols behaved alike. For a given compound the decomposition temperature and rate as well as the product distribution varied considerably with reaction conditions. The phenols themselves seem to pyro-lyze under equilibrium conditions slowly above 250°C. For their alkali salts the onset of decomposition is sharp and around 350°C. The reaction itself is exothermic. Preliminary results indicate that heavy ions such as cupric ion may decrease the decomposition temperature. 

Recently, several reports of the flame-retardant properties of boron-containing bisphenol-A resins have appeared from Gao and Liu.89 The synthesis of a boron-containing bisphenol-A formaldehyde resin (64 and 65) (Fig. 42) from a mixture of bisphenol-A, formaldehyde, and boric acid, in the mole ratio 1 2.4 0.5, has been reported.893 The kinetics of the thermal degradation and thermal stability of the resins were determined by thermal analysis. The analysis revealed that the resin had higher heat resistance and oxidative resistance than most common phenol-formaldehyde resins. 

On the basis of an IR study of some s-triazines and HA systems, several authors reported that ionic bonding took place between a protonated secondary amino group of the s-triazine and a carboxylate anion on the HA [17,146,147]. Successive studies, mainly conducted by IR spectroscopy, confirmed previous results and also provided evidence for the possible involvement of the acidic phenol-OH of HA in the proton exchange of the s-triazine molecule [17, 146-150]. Differential thermal analysis (DTA) curves measured by Senesi and Testini [146, 147] showed an increased thermal stability of the HA-s-triazine complexes, thus confirming that ionic binding took place between the interacting products. 

In the case of highly cross-linked material, water is not released until above 400°C, and decomposition starts above 500°C as confirmed using differential thermal analysis (DTA).55 The amount of char depends on the structure of phenol, initial cross-links, and tendency to cross-link during decomposition. The main decomposition products may include methane, acetone, CO, propanol, and propane. 

The constitnents of binary phenol mixtnres can be identihed by differential thermal analysis of a sample to which any of the aroyl chlorides 184-186 has been added. The thermogram is compared with a bank of differential thermograms of phenols, binary phenol mixtures and binary phenol derivatives. Most snch systems show weU-resolved endotherms corresponding to the melting points of the phenols and their acylated derivatives. The method is proposed for rapid identification of phenols in the solid state . 

Not only can molecular design improve the miscibility with other oils, it can also confer ILs with special functions, such as antioxidation and the ability to adapt to a broader temperature range. We synthesized three imidazolium-based ILs containing sterically hindered phenol groups with antioxidant functions and evaluated the tribological behaviors of these ILs as additives for PEG appfication in steeFsteel contacts on an Optimol SRV-IV oscillating reciprocating friction and wear tester, as well as on MRS-IJ four-ball testers [100]. The rotary bomb oxidation test (RBOT) test, thermal analysis, and Cu strip test results revealed that synthesized ILs possessed excellent antioxidation capability. 

As indicated in the previous sections, the antioxidant content in plastic material is often determined by chromatographic methods. Another widely used technique for polymer characterization is thermal analysis with differential scanning calorimetry (DSC). When the oxygen induction time (OIT) for a sample containing a phenoHc antioxidant is measured, a significant oxidative exothermic response is obtained in the DSC when all the phenolic antioxidant in a sample is consumed. The OIT is thus directly related to the antioxidant content in the material and to the stabihzing function, i.e. the antioxidant efficiency in the sample, if the consumption of phenolic antioxidants obeys zero-order kinetics at the temperature used [44]. Table 1 shows the amount of the antioxidant Irganox 1081 in polyethylene (PE) determined by HPLC and extraction by microwave assisted extraction (MAE),... 

Keywords Hydroialciie-likc compounds Hydroxylation of Phenol Selective oxidation Structure-activity relationships In situ powder X-ray diffraction In situ DRIFT FT-IR spectroscopy Thermal analysis (TGA-DTA-EGA-TPRO) Synthesis methodology Influence of reaction parameters Ordered network Synergism... 

Thermal analysis is applied to get information about transition temperatures, decomposition characteristics, and the crosslinking process of phenolic resins. Solid, liquid or gelled phenolics can be investigated by thermal analysis because of a variety of different sample vessels or attachments. 

Only 0.1 pg to lOmg of phenolic material is necessary for thermal analysis. However, the experimental data are influenced by the theimal and mechanieal histoiy of the phenolic material, its dimensions and mass, the atmospheric composition in its region, and the heating and cooling rates, used for the experiment [243]. 

This instrument has provided interesting insights into properties of phenolics as well as those of diaUyl phthalate, thermoset polyester, silicones, and epoxies, by indicating the abihty of thermosets to retain their modulus at elevated temperatures. See also thermal analysis. 

In this communication we present the results of an FTIR study of the blend system poly(bis-phenol A-carbonate) (PC) - PCL. This is a complex blend system which contains two crystallizable polymers with large differences in the crystalline melting points (T ) and glass transition temperatures (Tg). Cruz, et al.have demonstrated from thermal analysis and dynamic mechanical testing that blends of PC and PCL have a single Tg which is dependent only on the composition of the blend and conclude that the amorphous phase is miscible. These authors also concluded that the miscible amorphous phase results primarily from physical rather than chemical interactions between the polymers. 

Thermal decompositions have been studied most effectively by mass spectroscopic thermal analysis, thermogravimetric analysis, and electrical conductivity. Several analytical characterizations of phenolic resins have recently been reported, making use of a variety of properties, including expansion coefficients, " specific heat capacity, ultrasonic properties, dipole moments, and laser light scattering. Recently, high-temperature properties of reinforced phenolic components have been studied by Goetzel. ... 

Thermal Analysis Curves of Polymers Sample Phenolic resin. 

Siegmaim A and Narkis M (1977), Thermal analysis of thermosetting phenolic compounds for injection molding , J Appl Polym Sci, 21, 2311—2318. 

Thus the kinetics of thermal oxidative degradation has been studied by thermogravimetry" and the anti-oxidant ability of phenol and phosphorus derivatives have been evaluated by differential thermal analysis. Studies of the effect of red phosphorus and phosphorus and bromine"- on d adation bdiaviour and their role as fire-proofing agents has been described. Bis(ketimines) have been evaluated as reactive additives for viscosity stabilization in the melt."... 

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