Thermal degradation of epoxy resins

The scission reactions can take place at various weak spots. The breakdown of bisphenol A segments produces phenol [511]  

The main differences that were observed between amine-cured and anhydride-cured resins are [511]  

The amine cross-linked resin generated more water and hydrogen, because they contained more -CH2-CHOH-CH2- groups. 

Scissions of anhydride-reacted resins tend to regenerate the anhydride and release CO and CO2 in large quantities 

The aliphatic segments of the amine cross-linked resins yield more acetaldehyde than acetone. The reverse is true of the anhydride-cured resins. This is thought to be due to preferential rupture of carbon-nitrogen bonds [511]  

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D.P. Bishop and D.A. Smith, Combined pyrolysis and radiochemical gas chromatography for studying the thermal degradation of epoxy resins and polyimides. I. The degradation of epoxy resins in nitrogen between 400° and 700°C. J. Appl. Polym. Sci., 14, 205 (1970). 

A comprehensive study of the thermal degradation of epoxy resins has been reported by Lee [239]. Their stability was found to be lower than that of polycarbonate, polyphenylene sulphide and teflon (Fig. 64). 

Patussi V, Kokelj F, Buttazzi P (1995) Occupational airborne allergic contact dermatitis due to 3-amino-methyl-3,5,5-trimethylcyclo-hexylamine. Contact Dermatitis 32 239 Peltonen K (1986) Thermal degradation of epoxy powder paints (Doctoral dissertation). University of Kuopio, Kuopio, Finland Pigatto PD, Bigardi AS, Cusano F (1995) Contact dermatitis to cocamidopropylbetaine is caused by residual amines relevance, clinical characteristics, and review of the literature. Am J Contact Dermatitis 6 13-16 Potter WG (1975) Uses of epoxy resins. Newnes-Butterworths, London... 

The TFG-analysis of epoxy resins depends on the defined thermal breakdown of the polyadducts to low molecular, mostly phenolic conqrounds, under eolations of thermolysis (T ax < 500 °C). The medianisms of degradation which r ly here have been extensively studied and accord with our aiuil3rtical results According to this, the thermal breakdown of epoxy resins b ins with dehydration or dehydrogenation of the secondary alcohol function. This is followed by homol3rtic and/or... 

Participation of radical products of thermal degradation of PMBs in the epoxy resin curing process at high temperatures. 

Thermal Stability and Conductivity. Thermal degradation temperature of PMMA, PS, and PVA (poly(vinyl alcohol)) nanocomposites shifts up by 10-100°C. During combustion [179], nanoparticles form a network of char layers that retards the transport of decomposition products. The thermal conductivity of epoxy composites is four times higher than that of the neat epoxy resin with 5 wt% loads. 

An early use of the technique was reported by Lin, Bulkin Pearce in 1979 (6). Those authors investigated thermal degradation of several epoxy resins cured with... 

Denq and co-workers [17] applied a variety of techniques in their study of the thermal degradation behaviour of epoxy resins with propyl ester phosphazine ... 

Various other works have discussed the application of MS and other techniques in thermal degradation. Studies have been made on a nnmber of epoxy resins [18-20] based on DGEBA. These inclnde tetraglycidyl ether tetrakis (hydroxyphenol) ethane [17], araldite-epoxy resins [18]. 

In the last years the thermal behavior of carbon fibre reinforced epoxy resins has been investigated by different research groups [50]. Regnier et al. performed a kinetic study on the thermal degradation of carbon fibre/epoxy composites, both in air and in inert atmosphere. The thermal degradation of the composites occurred in three stages [51]. The presence of vapour-grown carbon nanofibres into the epoxy resin matrix did not influence the thermal stability of the resin. The decomposition temperatures in the case of composites were almost the same with the decomposition temperature of epoxy resin [52]. 

The incorporation of other type of nanoparticles, such as CuO, Ti02, silsequioxanes was found to affect the thermal degradation of the thermosetting materials. The thermal stability of the epoxy resin/cupric oxide (CuO) nanocomposites in air atmosphere was improved by the presence of CuO nanoparticles. Furthermore, the presence of these nanoparticles affected the degradation mechanism of the epoxy resin [72]. 

In the case of Ni-La-Fe-O/epoxy nanocomposites, the thermal degradation showed a more complicated behavior than the neat epoxy resin, with two peaks in the 300-475 °C temperature range. Moreover, the thermal stability of the resin decreased in the presence of Ni-La-Fe-0 nanoparticles, due to the fact that these nanoparticles may act as catalysts to degrade the epoxy matrix [76]. 

Saad, G.R., Efhamid, E.E.A., Elmenyawy, S.A. Dynamic cure kinetics and thermal degradation of brominated epoxy resin-organoclay based nanocomposites. Thermochim. Acta 524, 186-193 (2011)... 

Jash and Wilkie [86] reported that even when the fraction of clay was as low as 0.1 wt% the PBQiR in a cone calorimeter was lowered by 40 %. Lee et al. [87] demonstrated that incorporation of 6, 8 and 10 wt% of MMT into epoxy resin increased linearly the char yield firom 9.1 to 15.4 % reducing the thermal degradation of the epoxy matrix. Nazare et al. [88] studied the flammability properties of unsaturated polyester resin with nanoclays using cone calorimetry. The authors verified that the incorporation of 5 wt% of nanoclays reduces the PHRR by 23-27 % and THR values by 4-11 %. While incorporation of condensed-phase flame retardants (such as ammonium polyphosphate, melamine phosphate and alumina trihydrate) reduce the PHRR and THR values of polyester resin, the inclusion of small amounts of nanoclay (5 % w/w) in combination with these char promoting flame retardants causes total reductions of the PHRR of polyester resin in the range 60-70 %. Ammonium polyphosphate, in particular and in combination with polyester-nanoclay hybrids show the best results compared to other flame retardants. 

Gao Ming, Wu Weihong, and Xu Zhi-Qiang. Thermal degradation behaviors and flame retar-dancy of epoxy resins with novel silicon-containing flame retardant. J. Appl. Polym. 

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