Thermal oxidation of polymers

In the depolymeri2ed scrap mbber (DSR) experimental process, ground scrap mbber tines produce a carbon black dispersion in ok (35). Initially, aromatic oks are blended with the tine cmmb, and the mixture is heated at 250—275°C in an autoclave for 12—24 h. The ok acts as a heat-transfer medium and swelling agent, and the heat and ok cause the mbber to depolymeri2e. As more DSR is produced and mbber is added, less aromatic ok is needed, and eventually virtually 100% of the ok is replaced by DSR. The DSR reduces thermal oxidation of polymers and increases the tack of uncured mbber (36,37). Depolymeri2ed scrap mbber has a heat value of 40 MJ/kg (17,200 Btu/lb) and is blended with No. 2 fuel ok as fuel extender (38). 

Studies of thermal oxidation of polymers are usually carried out as accelerated by raising temperature of the sample so that the oxidation can take place in a considerably short time scale. This makes any extrapolation to lower temperatures unreliable since many processes are involved in degradation and several of these may become rate-limiting as the temperature is changed. This is particularly valid when such extrapolation is performed through the melting range. 

Chemiluminescence in Thermal Oxidation of Polymers Apparatus and Method... 

The addition of an external initiator considerably accelerates the thermal oxidation of polymers by reducing the induction period. Recently,... 

The dimers of type IV do not affect the course of tetrahydronaphthalene oxidation31, 32l They may be considered as inert admixtures from the view of thermal oxidation of polymers. 

The Effect of Corrosion Inhibitors on Thermal Oxidation of Polymers... 

Shibryaeva L.S.,Popov A. A., Zaikov G.E. (2006). Thermal Oxidation of Polymer Blends. Ch.2"Structure effects in thermal oxidation of polyolefines".Leiden, Boston VSP P.35-55. ISBN-13 978-90-6764-451-8 ISBN-10 90-6764-451-X. 

It functions both as a radical scavenger, reacting with peroxy radicals, and as a decomposer of hydroperoxides formed during thermal oxidation of polymers. 

Processing of polyolefins requires high temperatures (150-300°C), depending on the type of polymer. At these temperatures thermal oxidative and mechanochemical degradations occur. The main processes observed during the thermal oxidation of polymers are the formation of carbonyl groups... 

The rates of photo- (and/or thermal) oxidation of polymer films are usually measured by monitoring the hydroxyl (OH/OOH) group formation (/qoh) at 3450-3400 cmand/or carbonyl (CO) group formation Iqo) at 1720-1710cm using the following expressions, respectively ... 

During the photo- (and/or thermal) oxidation of polymers, various unsaturated groups, which can be detected by IR spectroscopy (Table 10.19), are formed in many cases [27, 1218, 1617]. 

The CL intensity relates to the concentration of peroxide radicals and therefore makes CL an ideal tool for following the thermal oxidation of polymers in real times. CL images can be recorded at different oxidation times. However, the OFT of the polymer samples is defined as the sudden increase of the CL signal (onset) from the baseUne level (see Figure 31). 

---