Republic, and was attended by about 1OOO participants. During the conference 275 lectures and 610 posters were presented in 8 microsymposia. The topics of these microsymposia were:

No abstract

Acta Polymerica 38 (1987) Nr. 5 260 DONTH, KRETZSCHMAR e t al. : Influence of the chain-end mobility on the melt crystallization GOWSKI, T. M., KRYSZEWSKI, M., and PVCHERZ, J . : Acta Cryst. C 42 (1986) 172. ,Carl Schorlemmer" Leuna-Merseburg, Sektion Physik, DDR-4200 MerseburgHindering and final blocking of the normal melt crystallization in central ethylene oxide (EO) blocks by methyl methacrylate (MMA) end blocks of increasing lengths in ABA type triblock copolymers synthesized anionicallg in a new way are investigated by differential scanning calorimetry and X-ray scattering. Experimental studies of glass transitions, low temperature nucleation, and the morphologic ten-nanometer structure are included. Low percentage amounts of long homo-PEO chains can crystallize in a n ABA matrix which otherwise is not normally crystallizable. It is concluded from the experiments that in our systems with PEO molecular masses up to 50000 g/mol t h e motion of the chain ends is necessary for melt crystallization under normal conditions. DONTH, KRETZSCHMAR et al.: Influence of thr chain-end mobility on the melt crystallization Actr Polymerica 38 (1987) Nr. 5 261 EinfluP der Kettenendenbeweglichkeit auf die Schmelzkristallisation von Ethylenoxid-(B)-Sequenzen in Systemen, die Diblock AB-und Triblockcopolymere ABA mit Methylmethacrylat (A) enthaltenDie Behinderung und letztliche Blockierung der normalen Schmelzkristallisation von zentralen Ethylenoxid( E 0 ) -Blocken durch Methylmethacrylat-(MMA)-Endblocke ansteigender Lange in Triblockcopolymeren vom Typ ABA, anionisch auf einem neuen Weg synthetisiert, wurden mit Hilfe der differentiellen Scanning-Calorimetrie und der Rontgenstreuung untersucht. Experimentelle Untersuchungen des Glasiihergangs, der Keimbildung bei tiefen Temperaturen und der morphologischen Zehn-Nanometer-Struktur werden eingeschlossen. Geringe Mengen (Prozentbereich) langer Homo-PEO-Ketten konnen in einer ABA-Matrix kristallisieren, welche sonst normal nicht kristallisierbar ist. Aus den Experimenten wird geschlossen, daB in den untersuchten Systemen mit PEO-Molekiilmassen bis zu 50 000 g/mol eine Bewegung der Kettenenden notwendig ist fur die Schmelzkristallisation unter normalen Bedingungen. Bnufinue not3ewnocmu ?conqoe yened na Kpucmumaaqim qened amuneno~cuda ( B ) e cuemeMax ~~~~J Z O U H I A X (AB) u mpu6nounb~x cono.nu&epoe A B A c Memuwfiemalcpmamo~ ( A )npOBeAeH0 H3YYeHMe 3aMeAJleHHR R OKOHYaTeJIbHOrO IIpeKpaWeHHH HOpMaJIbHOfi KpHCTaJIJIH3aqMM TpEI6jIOYHbIX COIIoJIRMepOB 3THJIeHOKCHAa (30) M MeTHJIMeTaKpRJIaTa (MMA) IIpH yBeJIR9HBaIOqHXCH AJIHHaX KOHeYHbIX ~JIOHOB C IIOMOqbIO MeTOAa EI PaCCeHHHFI PeHTreHOBCKHX JIyYefi. 06pa31(ar CHHTe3HpOBaJIHCb IHHOHHbIM c11oco6oM. npOBeneH0 3KCIIepHMeHTaJIbHOe H3y9eHHe IIpOUeCCa CTeKJIOBaHHH, HH3KOTeMIIepaTypHofi HyKJleaVRH Ei MOp@OJIOI'H-YeCKOfi CTPYKTYPbI B 06nac.r~ 10 HM. &IHHHbIe UenEI r o~o -n a o IIpR HH3KOM PIX COAepWaHHH MOryT HpHCTaJIJIEI30-BaTbCH B MaTpHqe ABA, KOTOPaFI 0 6~9~0 He KpHCTaJIJIH3yeTCH. CAeJIaH BbIBOA, 9 T O B HalIIHX o6pasqax, COAepWaWkiX n30...

In the last years several attempts have been made in order to lower the emissions from carbon bonded refractories by keeping or improving the mechanical, thermal and chemical properties.The introduction of carbo-resins opens the horizon for a low emission binder system in the so called cold processing of carbon bonded refractories. In terms of this work a variety of phenolic resin binders has been combined with carbo-resin in order to improve the anisotropic structure for advanced chemical and thermo mechanical properties with 14 wt.% residual carbon. Samples from industrial bricks have been used in order to measure the cold crushing strength, the hot modulus of rupture and the oxidation behaviour. The microstructure has been evaluated due to SEMmicrographs and porosimetry. In a further step corrosion finger tests have been carried out by simulating the oscillation of the mould and relative movement of the steel and the slag against the refractory component. The investigations have been completed by flexibility measurements in a special device by defining the stress/strain behaviour.Due to the new binder combinations the task of lowering emissions as well as improving the mechanical and thermal performance has been achieved.

The change of tacticity of methacrylate blocks in the anionic block copolymerization of ethylene oxide with methyl methacrylate or rerr-butyl methacrylate as function of the number of monomeric units in the poly(ethy1ene oxide) (PEO) sequences formed in the first polymerization step, was studied. The fraction of the syndiotactic triads of the polymethacrylates was found to increase with the DP of the PEO precursor. When the plateau value was reached, the tacticity was similar to that of poly(methy1 methacrylate) initiated by alkali alkoxides when solvated with crown ethers. The variation of the tacticity was smaller with rerr-butyl methacrylate than with methyl methacrylate. The growth reaction of methacrylate monomers was found to follow Bernoullian statistics. It is assumed that the solvation of the counterions increases with increasing of the monomeric units in the starting poly(ethy1ene oxide) blocks.