Zeitschrift für Angewandte EntomologieVolume 23, Issue 2 p. 281-293 Holzzerstörende Bockkäferlarven Ergates faber L., der Mulmbock, Leptura rubra L., der Rothalsbock und Hylotrupes bajalus L., der Hausbock Karl Eckstein, Karl Eckstein Berlin.Search for more papers by this author Karl Eckstein, Karl Eckstein Berlin.Search for more papers by this author First published: January/December 1937 https://doi.org/10.1111/j.1439-0418.1937.tb00436.xCitations: 4AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat Citing Literature Volume23, Issue2January/December 1937Pages 281-293 RelatedInformation

Sequential copolymerizations of trimethylene carbonate (TMC) and l-lactide (LLA) were performed with 2,2-dibutyl-2-stanna-1,3-oxepane as a bifunctional cyclic initiator. The block lengths were varied via the monomer/initiator and via the TMC/l-lactide ratio. The cyclic triblock copolymers were transformed in situ into multiblock copolymers by ring-opening polycondensation with sebacoyl chloride. The chemical compositions of the block copolymers were determined from (1)H NMR spectra. The formation of multiblock structures and the absence of transesterification were proven by (13)C NMR spectroscopy. Differential scanning calorimetry (DSC), wide-angle X-ray scattering (WAXS), and dynamic mechanical analysis (DMA) measurements confirmed the existence of a microphase-separated structure in the multiblock copolymers consisting of a crystalline phase of poly(LLA) blocks and an amorphous phase formed by the poly(TMC) blocks. Stress-strain measurements showed the elastomeric character of these biodegradable multiblock copolymers, particularly in copolymers having epsilon-caprolactone as comonomer in the poly(TMC) blocks.

The goal of the investigation presented here is the development of extremely hydrophobic materials based on polysulfone that can be applied, for instance, as fouling-resistant membrane materials. The concept used is the addition of semifluorinated polymers to polysulfone in suitable blend compositions. The influence of molecular parameters like chain structure of the semifluorinated polymer (segmented block copolymers, random copolymers) and segment molecular weight on the state of phase separation in the bulk and its influence on the surface properties have been systematically examined. It could be shown that segmented block copolymers with semifluorinated polyester segments with intermediate segment molecular weight are more suitable in blends with polysulfone than random polysulfone copolymers having semifluorinated side chains with respect to form homogeneous thin films (coatings) with highly non-wetting properties.

The goal of the investigation presented here was to evaluate the influence of semifluorinated side chains on the bulk structure and the surface properties of polysulfones with different chain structure. Thus, segmented block copolymers consisting of polysulfone and semifluorinated aromatic polyester segments as well as polysulfones having semifluorinated side chains randomly distributed over the polymer backbone were synthesized and characterized. Oxydecylperfluorodecyl side chains were used because of their strong tendency for self-organization. The influence of the chain architecture on the self-organization as well as on the surface properties, particularly the wetting behavior, was examined. It could be shown that despite of the higher self-organizing tendency of block copolymers the surface properties of both polymer types are comparable and depend only on the concentration of side chains.

Linking segments of two different polymers in block copolymers offers the opportunity to combine their macroscopic properties and to design tailor-made materials. This is shown for segmented block copolymers (A-B) n in which the basic segment is polysulfone. Incorporation of either hydrophilic and or hydrophobic segments results in a dramatic change of surface properties which is also correlated to the bulk structure of the block copolymers.

The phase separation behaviour of block copolymers of the type (A–B) n (segmented block copolymers, multiblock copolymers) containing segments with different degrees of flexibility was investigated using a stepwise variation of the incorporated blocks A and B. Amorphous/rigid blocks (polysulfone segments) were systematically combined with amorphous/flexible blocks (poly(tetramethylene glycol), semiflexible/nematic blocks (different kinds of aromatic polyesters and poly(ester imides) as well as semicrystalline fluorinated polyester blocks). All multiblock copolymers were synthesized using a conventional transesterification polycondensation in the melt and the polycondensation results are discussed. The phase separation in the synthesized block copolymers was investigated both experimentally and theoretically. Flory–Huggins interaction parameters of the block copolymers were calculated and used together with mean field calculations in order to understand the phase separation behaviour of all block copolymers correlated to their chemical structure. On the other hand, the onset of phase separation in a series of block copolymers with a systematic variation of block molecular weights was examined experimentally, mainly by DSC and SAXS. Finally, the question is discussed whether or not the degree of phase separation in the investigated systems determines the properties of the polymers or not. This is for example outlined for the mechanical properties and, in particular, the surface properties of fluorinated block copolymers.

One mechanism for compatibilization of immiscible polymer blends is adding block copolymers (BCP) that consist of segments chemically comparable to the parent homopolymers in the blend. BCP do both, emulsify the disperse phase to give smaller particles as well as increase the interfacial adhesion between the phases. The influence of segmented BCP in blends of immiscible high-performance polymers was investigated systematically by variation of the flexibility of the BCP segments. It was shown that the stiffness of the second segment in polysulfone (PSU) block copolymers as well as the PSU segment molecular weight determine the intermixing between the BCP and the PSU matrix.

By means of PSU/LCP multiblock copolymers with different molecular weights of the blocks in binary solution cast blends it was shown that the interpenetration of the PSU phase of the block copolymer and the PSU matrix leads to a partial miscibility of the blend, if the molecular weight of the PSU segments of the block copolymer exceeds the entanglement molecular weight at least twice. From these results, a certain interdiffusion of the PSU segments of the MBCP's and the PSU homopolymer in their interface was concluded. XR as well as NR experiments were used to examine the behavior of layered systems as a function of the annealing temperature in order Co determine the interfacial thickness between the layers as a measure for the interaction.

The phase structure of polysulfone/poly(tetramethylene oxide) multiblock copolymers (PSU/PTMO BCP) strongly depends on the molecular weight of the coupled blocks. Non-phase separated structures are obtained using low molecular PTMO blocks. These block copolymers show a single T-g that follows the miscibility rule by Fox. Block copolymers with longer PTMO blocks have a phase separated morphology that is characterized by the coexistence of an amorphous PSU phase, an amorphous PTMO phase as well as crystallized PTMO domains.The influence of the block copolymer composition in blends with high molecular PSU was investigated. Blends of PSU and PSU/PTMO block copolymers are miscible if the molecular weight of the PSU segment exceeds the entanglement molecular weight twice. Otherwise, partial phase separation into a PSU-rich and BCP-rich phase is observed in the blend. (C) 1999 Published by Elsevier Science B.V. All rights reserved.

Polysulfone was modified by incorporation of hydrophilic poly(oxy-1,4-butanediyl) [synonyms: poly(tetramethylene ether glycol), PTMG, poly(tetrahydrofuran), poly(THF), poly(tetramethylene oxide)] units into the polysulfone chain resulting in the formation of segmented block copolymers. These block copolymers were prepared by a melt transesterification procedure. The influence of the molecular weights of both, polysulfone and PTMG segments on the solid phase structure, the thermal behavior, the wetting behavior as well as the surface composition of the products was studied. It was shown that the incorporation of hydrophilic PTMG segments leads to a significant hydrophilization of polysulfone that partially results in an enhanced swelling ability.

The use of multiblock copolymers for the compatibilization of immiscible polymer blends is controversially discussed in the literature. Investigations have been carried out to estimate the effect of multiblock copolymers containing segments of a liquid crystalline polyester (LCP) and polysulfone (PSU) segments in blends of the based homopolymers. One goal was to determine whether multiblock copolymers provide an opportunity for compatibilizing PSU/LCP blends. By using PSU/LCP multiblock copolymers with different molecular weights of the blocks in the appropriate binary, solution-casted blends, it was shown that the interpenetration of the polysulfone phase of the block copolymer and the PSU matrix leads to an improved miscibility of the blend. This effect is retained in ternary blends of PSU, LCP, and the multiblock copolymer, assuming a certain critical molecular weight of the multiblock copolymer segments. In addition, some mechanical characteristics of PSU/LCP melt blends such as the E-modulus and fracture strength are improved by adding long-segmented multiblock copolymers. © 1997 John Wiley & Sons, Inc. J Appl Polym Sci 66: 2293–2309, 1997

Multiblock copolymers offer the possibility to combine the properties of different polymers. Thus, new materials with tailor-made unique properties are available by coupling of different suitable polymeric segments. The goal of the work discussed in this paper was to combine advantageous properties of liquid-crystalline polymers (LCP) with those of polysulfone (PSU). Therefore, liquid crystalline poly(ethylene terephthalate-co-1,4-oxybenzoates) were connected with PSU oligomers. Chemically homogeneous multiblock copolymers with high molecular weight were obtained by a melt transesterification procedure. It was demonstrated by wide angle x-ray scattering (WAXS), polarizing microscopy, transmission electron microscopy (TEM), and differential scanning calorimetry (DSC) that the properties of the multiblock copolymers (solid phase structure, phase behavior, morphology, glass transition, and melting behavior) can be balanced by the segment length of the incorporated blocks. The investigations clearly reveal the existence of a two-phase structure. However, a change of properties compared to the corresponding homopolymers refers to certain interactions between the phase due to the chemical connection of the LCP and PSU segments. © 1996 John Wiley & Sons, Inc.

The case histories of 79 children with idiopathic thrombocytopenic purpura (ITP) were retrospectively analyzed. The course was acute in 53 patients, chronic in 24, and recurrent in 2. In cases of acute ITP (aITP) the duration of disease in children who had received high-dose immunoglobulin therapy was on average 3.4 days shorter than in the untreated group, while in children who were given glucocorticoid therapy it was longer. Among the cases of chronic ITP, splenectomy in 5 out of 7 patients caused the thrombocyte count to return to normal, while in the other patients the increase was at least so high that there was no reason to fear the occurrence of hemorrhage. If the course is complicated in a case of chronic ITP, surgery should be considered, especially as the alternatives (glucocorticoids, high-dose immunoglobulin, vincristine) only led to a temporary success in our patients and hence only appear indicated in certain situations (e.g., when surgery is planned).

The case histories of 79 children with idiopathic thrombocytopenic purpura (ITP) were retrospectively analyzed. The course was acute in 53 patients, chronic in 24, and recurrent in 2. In cases of acute ITP (aITP) the duration of disease in children who had received high-dose immunoglobulin therapy was on average 3.4 days shorter than in the untreated group, while in children who were given glucocorticoid therapy it was longer. Among the cases of chronic ITP, splenectomy in 5 out of 7 patients caused the thrombocyte count to return to normal, while in the other patients the increase was at least so high that there was no reason to fear the occurrence of hemorrhage. If the course is complicated in a case of chronic ITP, surgery should be considered, especially as the alternatives (glucocorticoids, high-dose immunoglobulin, vincristine) only led to a temporary success in our patients and hence only appear indicated in certain situations (e.g., when surgery is planned).