Thermal degradation/oxidation polymers

Levi, Literature Survey on Thermal Degradation, Thermal Oxidation, and Thermal Analysis of High Polymers , PLASTEC Note 7 (1963)... 

Literature Survey on Thermal Degradation, Thermal Oxidation, and Thermal Analysis of High Polymers. Ill , PLASTEC Note 20 (1969) 29) N T. Baldanza, Literature Search Injection Molding Processing Parameters , PLASTEC Note 21 (1969) 30) A.H. Landrock, Polyurethane... 

Gugumus F. Re-examination of the thermal oxidation reactions of polymers 2. Thermal oxidation of polyethylene. Polym Degrad Stab 2002 76(2) 329-40. 

The enhanced thermal stability of the silicones has been postulated by Andrianov and Sokolov (26) to be due to (1) the high energy of the SiOSi bond, (2) the stability of organic radicals to oxidation at the silicon atom, (3) stable SiOSi bond formation within the polymer after partial degradation, and (4) the formation of a layer of silicon-oxygen bonds on the surface of the polymer during thermal oxidation. 

A series of tests has allowed to obtain data that shows introduction of an ion of metal as a matrix and structurization of polymer cross-section metilen bridges due to formaldehyde has led to increase in stability of polymer to thermal-oxidative degradation. Besides it has been proved that ions of nickel possess greater structuring ability. 

Results of research thermal degradation of BIP-Ni, BIP-Zn and BIP-Co and initial gelatin by method of differential thermal analysis have shown, that introduction of template ion raises stability of polymer to thermal-oxidative degradation. 

This chapter deals with the subject of flammability of polymers where thermal, oxidative, and radiative degradations all play very significant roles. Flanunability of polymers is a complex subject and has been discussed in other books and review articles by various authors [12-22],... 

The correlation between a polymer s thermal oxidative degradation and its combustion under diffusion flame conditions may represent an interesting specific application. In general, the solid phase polymer reaction can play a very important role in reduction of polymer combustibility. 

Dielectric analysis has also been applied to study polymer thermal ageing [894], e.g. of adhesive bonded structures [895]. Dielectric loss is a means for detecting early steps in polymer degradation by oxidation, although nowadays CL is a strong competitor. The dielectric behaviour of post-irradiation oxidised PP/HALS was also reported [796]. Dielectric analysis has not been extended to many elastomer applications. Dissociation and mobility of salt complexes as heat stabilisers in PA4.6 have been investigated by means of DIES the technique was also used to study thiourea-doped PVAL [903]. 

Alvinox P is utilized to protect polymers from thermal oxidation particularly during processing. It acts essentially as a decomposer of hydroperoxides. Optimum performance is obtained when the product is used in combination with antioxidants (hindered phenols and/or thioethers) which additionally protect the polymer against long-term heat degradation. 

In order to protect polymers against thermal oxidation, it is necessary to add thermostabilizers and/or antioxidants, which themselves contain many chromophoric groups, which can further photoinitiate degradation of the polymer. 

Protection of polymers against thermal and photo-oxidative degradation is achieved with appropriate stabilizers that ensure the desirable polymer properties throughout the entire service life of the polymer. Compatible and polymeric stabilizers usually give the best protection. In order to avoid migration and evaporation, polymeric stabilizers are used. 

There have been many studies on the thermal and thermo-oxidative degradation of PMMA.23 24 It is well established that the polymer formed by radical polymerization can be substantially less stable than predicted by consideration of the idealized structure and that the kinetics of polymer degradation are dependent on the conditions used for its preparation. There is still some controversy surrounding the details of thermal degradation mechanisms and, in particular, the initiation of degradation.31... 

CL must be very carefully purified to exclude small concentrations of (1) ferric ions which would catalyze die thermal oxidative degradation of polycaprolactam and (2) aldehydes and ketones which would markedly increase oxidizability of CL. The impurities in CL may retard die rate of CL polymerization as well as having a harmful effect on die properties of die polymer fiber. In die vacuum depolymerization of nylon-6, a catalyst must be used because in die absence of a catalyst by-products such as cyclic olefins and nitrides may form, which affects the quality of die CL obtained.1... 

L. Costa, G. Camino and L. Trossaarelli, "Thermal Degradation of Fire Retardant Chloroparaffin - Metal Compound Mixtures - Part I. Antimony Oxide,"Polym. Degradation and Stability, 5, 267 (1983). 

W. Zhao, T. Cao, and J.M. White, On the origin of green emission in polyfluorene polymers the roles of thermal oxidation degradation and crosslinking, Adv. Fund. Mater., 14 783-790, 2004. 

Thermal-oxidative degradation is an additional reason for yam breaks commonly observed during polymer processing as a consequence of leaks in the equipment. Frequent testing of tightness is therefore an important part of production... 

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