Epoxynovolak resin

An investigation of the thermal and thermooxidative stability of crosslinked polymers obtained from BPA/DC and BPA/DC compositions with BPA/ECH epoxide resin or epoxynovolak resin has demonstrated that the epoxy resin decreased the thermal stability of BPA/DC based non-modified polycyanurate [71]. The systems with epoxynovolak resin behave somehow better. 

It is advisable that the epoxide resin/hardener component has high Tg. A crosslinked IPN was obtained e.g. from epoxynovolak resin, pyromellitic dianhydride, triethanolamine (epoxide — acid anhydride reaction catalyst), BPA/DC and Zn acetate (cyclo-trimerization catalyst) [78],... 

A binder was obtained from an epoxynovolak resin, BPA/DC, BMI, dicyclopenta-diene, Zn acetate and dicumyl peroxide [94]. In a similar composition, BPA/DC prepolymer was used as curing and cyclotrimerization initiators and catalysts, catechol, triethylenediamine, Zn acetate and benzoyl peroxide are mentioned [95], Other compositions contain A1 acetylacetonate and a silicone resin [96], p-toluenesulfonic acid monohydrate and Zn octoate (for rapid curing) [97], or dicumyl peroxide and Zn octoate [98]. 

A binder for copper clad laminates contains the prepolymer from BPA/DC and A -(3,5-dimethyl-4-vinylphenyl)maleimide in methylethylketone, an epoxynovolak resin, Zn acetate and tert.butyl peroxide [100], In a similar composition, a prepolymer obtained from epoxide resin, BMI and bis(4-aminophenyl)methane was mixed with BPA/DC, Zn acetate and tert.butyl peroxide in solution [101]. 

Fire resistant polymers were obtained from brominated epoxynovolak resin, BPA/DC prepolymer, BMI, Zn acetate and benzoyl peroxide [103] or from an oligo-aspartimide (BMI-diamine reaction product), BPA/DC, 2,2-bis(3,5-dibromo-4-hydroxyphenyl)propane (i.e. Tetrabromo-Bisphenol A) and 2-ethyl-4-methylimi-dazole [104]. A mixture of BPA/DC, BMI and epoxide resin with brominated polycarbonate, copoly[oxy-2,6-dimethylphenylene)-(oxy-2,3,6-trimethylphenylene)] and a catalyst was also suggested [105],... 

Epoxynovolak resin and BPA/DC-BMI prepolymer, tert.butyl peroxide and Zn acetate [106, 107] or 2-phenylimidazole and other catalysts [108] were filled with wollastonite. Carbon-fiber reinforced composites were obtained using a binder, which consisted of BPA/DC, BMI, an epoxynovolak, 2-ethyl-4-methylimidazole and an organic solvent [109]. A BPA/DC-BMI prepolymer in methylethylketone was mixed with middle-molecular-weight epoxide resin (Epikote 1001), 2-ethyl-4-methyl-imidazole, Zn acetate and triethylenediamine thermal shock resistant GRP was thus obtained [110]. 

Molar excess of epoxynovolak resin was reacted with DDS highly branched aminoepoxide resin was thus obtained. The resin was then mixed with a non-modified epoxide resin, BPA/DC-BMI copolymer, benzoyl peroxide and /V-(3,4-dichloro-phenyI)-Ar, Ar -dimethyIurea (curing agent for the epoxy component) [116]. 

Two-layered GRPs for copper clad laminates are obtained with one layer consisting of the three-component system (e.g. BPA/DC, BMI, brominated epoxide resin, Zn octoate and triethylenediamine in methylethylketone). The other layer has the usual epoxy matrix (brominated epoxide resin, dicyandiamide as a hardener and 2-ethyl-4-methylimidazole as curing accelerator) [119]. As similar two-layered laminate contains BPA/DC, BMI, epoxynovolak resin, Zn acetate and triethylenediamine in the first layer and BPA/DC only with the same catalysts in the second layer [120]. 

Mechanical and thermal properties of the ACEC XLIII cured with an acid anhydride (cast profiles) and with PAFOs (a reinforced plastic) are compared with the properties of an epoxynovolak resin cured with the same curing agents (Tables 18 and 19). In addition to the high values of flexural strength at 200 °C, good thermal stability (weight loss of only 1.8% after 500 h at 200 °C) was found. 

Table 18. Properties of ACEC XLIII and an epoxynovolak resin cured with an acid anhydride...

Epoxy compound ACEC XLIII Epoxynovolak resin... 

Table 19. Properties of composites made of the ACEC XLIII and an epoxynovolak resin (UP-643) cured with PAFOs...

The data presented show that a proper selection of modifiers and curing parameters makes it possible to develop heat resistant composites with high temperature resistance. The composites are superior to similar materials based on BPA/ECH epoxy and epoxynovolak resins. 

The properties of the epoxide/cyanate compositions are inferior to those of non-modified cyanate polymers. They are, however, better in comparison with the properties of crosslinked BPA/ECH epoxide resin and epoxynovolaks [72]. Equimolar epoxide/cyanate ratio was recommended. Outstanding water resistance and dielectric properties at elevated temperatures are emphasized. In many patent applications, improved solvent resistance is mentioned. 

The modifying performance of cycloaliphatic monoepoxides in the curing processes of cycloaliphatic diepoxy compounds was described in [75]. ACECs are very efficient as modifiers of epoxyamine [76] and epoxynovolak [77-79] resins. The search for reactive diluents for epoxy compositions was initially directed towards an improvement of the processing characteristics, in particular the viscosity suppression, whereas the increase in mechanical strength and heat resistance was considered to be the result of the improved processing character-... 

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