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ABSTRACT:A new microwave-assisted method of synthesis of solid epoxy resins (SER) with desired epoxy-groups content is described. The method is based on the polyaddition of 4,4Ј-isopropylidenediphenol (BPA) to a lower-molecular-weight epoxy resin [Rü tapox 0162, epoxy value (EV) ϭ 0.57 mol/100 g] in the presence of 2-methylimidazole (2-MI), as a catalyst. Analogical syntheses were performed using conventional heating (i.e., electric heating mantle) for the comparison of properties of SER under both conditions. All the microwave reactions were carried out in the multimode microwave reactor Plazmatronika (Poland) with microwave frequency of 2.45 GHz and maximum microwave power of 600 W. The main advantage of the microwave process is twofold reduction of reaction time in comparison to the conventional heating. Values of EV, M n , M w , M w /M n , and degree of branching of the products obtained were determined. It was found that the molecular weight distribution and degree of branching in resins synthesized under microwave irradiation was comparable with those obtained under conventional heating and was not influenced by the reduction in reaction time.

Synthesis of elevated-molecular-weight epoxy resins with aid of microwaves RAPID COMMUNICATION Summary-A new method of synthesis of elevated-molecular-weight (E-M) epoxy resins with desired epoxy-groups content, based on polyaddition of bisphenol A to a lower-molecular-weight (L-M) epoxy resin (epoxy value EV = 0.57 mol/100 g) under microwave irradiation in the presence of 2-methylimidazole, as a catalyst, was described. Syntheses were carried out in a multi-mode microwave reactor "Plazmatronika" (Poland) of microwave frequency 2.45 GHz and maximal microwave power 300 W. Analogical syntheses have been done using conventional heating for the comparison of the methods. Values of EV, Mn, Mw and Mw/Mn of the products obtained have been determined. The main advantage of the process is twofold reduction of reaction time of the processes carried at microwave reactors in comparison to the conventional heating.

New solid state epoxy resins based on diglycidyl ether of 1,1-dichloro-2,2 bis (4-hydroxyphenyl), ethylene (BPC) and BPA epoxy resins in the reaction with BPC and BPA were developed. Solid epoxy resins were synthesised by the use of two different heating methods: conventional and microwave reactor. The use of microwave radiation as novel heating medium as an alternative to the conventional methods, which provide a quicker and more effective synthesis. The solid epoxies have high melting points higher than 100°C and the polycondensation degree remains between n ϭ 4 -12. Epoxy value stays low and occurs around 0,02-0,1. BPA epoxy resins and diglycidylether of BPC II were compared in terms of reaction speed. It can be seen that the reaction of BPC diglycidylether occurs approximately 20% quicker given the same reaction conditions of temperature, and balance of catalyst.

Przekazujemy P.T. Czytelnikom kolejny zeszyt tematyczny "Polimerów" pooewiêcony tym razem ¿ywicom epoksydowym. Tematyki tej dotyczy osiem pierwszych artyku³ów oraz artyku³ promocyjny. Redakcja sk³ada serdeczne podziêkowania profesorowi Piotrowi Penczkowi z Instytutu Chemii Przemy-s³owej im. prof. I. Mooecickiego za cenn¹ pomoc w przygotowaniu tego zeszytu. JAROS£AW GÓRCZYK 1) , DARIUSZ BOGDA£ 1) *) , JAN PIELICHOWSKI 1) , PIOTR PENCZEK 2) ywice epoksydowe o zwiêkszonym ciê¿arze cz¹steczkowymsynteza i charakterystyka termiczna Streszczenie-¯ywice epoksydowe o zwiêkszonym ciê¿arze cz¹steczkowym (EPzcc) otrzymywano w wyniku poliaddycji bisfenolu A (dianu) z ma³ocz¹steczkow¹ ¿ywic¹ epoksydow¹ w obecnooeci 2-metyloimidazolu (2-MI) jako katalizatora. Mieszaninê reakcyjn¹ ogrzewano b¹dŸ w sposób konwencjonalny, b¹dŸ te¿ z wykorzystaniem promieniowania mikrofalowego. Syntezê EPzcc prowadzono wobec trzech ró¿nych ilooeci katalizatora. Uzyskane w ten sposób produkty ró¿ni³y siê wartooeciami liczby epoksydowej (LE) oraz zawartooeci¹ drugorzêdowych grup OH (LOH).¯ywice te sieciowano za pomoc¹ dicyjanodiamidu (DCDA), oeledz¹c przebieg tego procesu metod¹ DSC. Badania EP zcc metod¹ analizy termograwimetrycznej wykaza³y, ¿e wprawdzie pocz¹tkowa temperatura rozk³adu ¿ywicy ulega po usieciowaniu niewielkiemu podwy¿szeniu, ale stabilnooeae termiczna w przedziale wy¿szej temperatury jest wyraŸnie gorsza ni¿ wyjoeciowej nieusieciowanej ¿ywicy. S³owa kluczowe: ¿ywice epoksydowe o zwiêkszonym ciê¿arze cz¹steczkowym, warunki syntezy, sieciowanie, odpornooeae cieplna. INCREASED MOLECULAR WEIGHT EPOXY RESINS-SYNTHESES AND THERMAL CHARACTERISTICS Summary-Increased molecular weight epoxy resins (EPzcc) were synthesized by polyaddition of bisphenol A and low molecular weight epoxy resin, in the presence of 2-methylimidazole (2-MI) as a catalyst. Reaction mixture was heated either conventionally or by microwave radiation. EPzcc preparation carried out using three various amounts of a catalyst (Table 1). The products obtained differed in epoxide equivalent value (LE) and secondary OH groups' (LOH) contents. The resins were cured with dicyandiamide (DCDA). The course of the process was monitored using DSC method (Table 2, Fig. 1 and 2). Investigations of EPzcc by thermogravimetry (Table 4 and 5, Fig. 3) showed that even though the initial temperature of resin decomposition slightly increased after curing, the thermal stability at elevated temperature was significantly worse than that characterizing the initial uncured resin.