摘要:

AbstractA group of polyion complexes (PICs) was checked as candidate for non‐thrombogenic biomaterials. To evaluate blood‐compatibility of different types of PIC, the interaction of the PICs with blood platelets was examined by passing fresh blood through a column packed with glass beads which were precoated with PIC. The course of morphological change of the platelets adhered on the surface was observed by scanning electron microscopy. The behavior (adhesion, aggregation, and deformation) of the platelets on the beads' surface was found to be significantly influenced by the mole ratio of polyanion to polycation in the PIC. The blood‐compatibility could be shown to depend also on the chemical structure of the polycation component of the PIC. Among the PICs examined, the newly synthesized PIC5showed the best results in terms of the number of adherent platelets and the degree of their deformation. The good blood‐compatibility of5is presumabley attributable to the easiness in getting to stoichiometric neutral

ISSN:0025-116X    

DOI:10.1002/macp.1980.021810701

出版商:Hüthig&Wepf Verlag    

年代:1980

数据来源: WILEY

摘要:

AbstractA new monomer for the preparation for polyimidines has been synthesized from 3,3‐diphenylphthalide. The starting material can be mononitrated on one of the pendant phenyl groups by the use of acetyl nitrate or nitronium tetrafluoroborate. The resulting nitrophthalide is then reduced to the amine with hydrogen over PtO2or with ammonium sulfide with overall yields of 85–90%. 3‐(p‐Aminophenyl)‐3‐phenylphthalide then can undergo self‐condensation to provide a new polyimidine with a rigid backbone structure which may be a candidate for liquid crystal formation. The condensation can take place at temperatures of 180–350°C, either in polyphosphoric acid or nitrobenzene as solvents, or without solvent in a sealed tube. The yield from the polymerization is as high as 89% and inherent viscosities range up to 0,19 dl/g. Thermal stabilities in air and nitrogen are as high as 520 and 565°C, respectively; however a significant difference occurs in thermal stability for different methods of synthesis. All polymers were soluble in chloroform, dimethylformamide and other

ISSN:0025-116X    

DOI:10.1002/macp.1980.021810702

出版商:Hüthig&Wepf Verlag    

年代:1980

数据来源: WILEY

摘要:

AbstractThe syntheses of a number of new comb‐like polymers are described, which contain mesogenic groups as side branches presenting models of low‐molecular liquid crystals of smectic type. The resulting polymers are capable to form an enantiotropic liquid crystalline phase, which may be defined as smectic, according to the terminology used for low‐molecular liquid crystalline substances. The thermodynamic limits of the liquid crystalline state in these polymers were determined, which made it possible to define the liquid crystalline state as a thermodynamically stable phase with spontaneously appearing anisotropy of properties (in particular, the optical anisotropy). The characteristic feature of the structure of these polymers was found to be the layer order of side groups providing — in combination with the packing of the mesogenic groups — the possibility of liquid crystalline properties. Only the mesogenic groups take part in the formation of the crystalline packing in these polymers, whereas the methylene chains are in the amorphous phase together with the backb

ISSN:0025-116X    

DOI:10.1002/macp.1980.021810703

出版商:Hüthig&Wepf Verlag    

年代:1980

数据来源: WILEY

摘要:

AbstractThe IR spectra (in the region of 400–3600 cm−1) of comb‐like polymers in crystalline, liquid‐crystalline, and fluid isotropic phases were studied, and the effect of the chemical structure of the long side chains on the crystalline and liquid‐crystalline states were examined. The spectroscopic criteria of phase transitions in comb‐like polymers were established and the fragments of the side chains involved in the formation of the liquid‐crystalline phase, we

ISSN:0025-116X    

DOI:10.1002/macp.1980.021810704

出版商:Hüthig&Wepf Verlag    

年代:1980

数据来源: WILEY

摘要:

AbstractThree new conjugated polymers with nitro‐substituted acenaphthenediylidene repeating units were prepared. The polymers which exhibit semiconductive and paramagnetic properties, differ in number and location of the nitro groups. The comparison of the polymer properties leads to the conclusion that in one of the polymers an intermolecular charge transfer complex could exist, thus improving its semiconductive propertie

ISSN:0025-116X    

DOI:10.1002/macp.1980.021810705

出版商:Hüthig&Wepf Verlag    

年代:1980

数据来源: WILEY

摘要:

AbstractThe oligomerization of ethylene in hexane, initiated bysec‐butyllithium (sec‐BuLi) complexed with tetramethylethylenediamine (TMEDA) was studied. The half‐order reaction in [sec‐BuLi‐TMEDA] and [PELi‐TMEDA](PELi = (polyethylene)lithium) supports the presence of aggregated dimer species. For the initiation as well as the propagation, a dissociation of these dimers (sec‐BuLi‐TMEDA)2and (PELi‐TMEDA)2has to be considered, the monomeric form being the only active one. The higher reactivity ofsec‐BuLi compared to PELi can be explained partly by a secondary carbanionic structure compar

ISSN:0025-116X    

DOI:10.1002/macp.1980.021810706

出版商:Hüthig&Wepf Verlag    

年代:1980

数据来源: WILEY

摘要:

AbstractLiving oligomers of ethylene obtained bysec‐butyllithium complexed with tetramethylethylenediamine (TMEDA) were deactived by oxygen. NMR and mass spectrometry, coupled with gas chromatography of the resulting product allowed us to follow the influence of TMEDA towards functionalization. The two productswere characterized. Apparently the ratio [TMEDA]/[sec‐BuLi] does not seem to influence the functionalization react

ISSN:0025-116X    

DOI:10.1002/macp.1980.021810707

出版商:Hüthig&Wepf Verlag    

年代:1980

数据来源: WILEY

摘要:

AbstractA phenomenological theory of the Phase Distribution Chromatography (PDC)‐separation effect is outlined and a theoretical equation for the measured PDC‐calibration curves is given. Assuming a reversible‐thermodynamical equilibrium in the polystyrene‐PDC‐column, only a relatively small part of the measured PDC‐calibration curves could be explained: namely those running below their tangents. In order to explain the whole sigmoidal shape of the experimental curves, a theory of steady state in the system sol/gel was developed assuming deformation of the polymer coil near the gel front due to the stress related to the velocity gradient. The resulting dynamical flow‐equilibrium differs highly from the reversible‐thermodynamic one at suitable low column temperatures. It leads to two typical calibration regions explaining the resolution power of the PDC‐column as a function of temperature. Analysis of the first one (reversible‐thermodynamical) starts with a three‐parameter partition function and leads to two contributions of the heat of transfer of aP‐mer from the gel into the sol of the column. These results are compared with those of Schulz, von Günner and Gerrens, and of Schulz and Horbach. In this way a physical interpretation of the three parameters in the partition coefficient of theP‐mer in the system gel/sol of t

ISSN:0025-116X    

DOI:10.1002/macp.1980.021810708

出版商:Hüthig&Wepf Verlag    

年代:1980

数据来源: WILEY

摘要:

AbstractN,N′‐diethylpseudoisocyanine chloride (PIC) forms compounds with various vinyl poly+ and DNA, but the shapes of the spectra of the dye‐polyanion compounds depend on the nature of the polyanions. PIC forms compounds with 1:1 polyanion/dye stoichiometries with DNA (native and denatured), polymethacrylate and poly(styrenesulfonate); and the spectra of these compounds do not show any pronounced metachromasia or red‐shifted J‐band. Polyacrylate and poly(vinyl sulfate) form compounds with polyanion/dye stoichiometry of 2:1, and give spectra with extremely sharp and red‐shifted J‐band. This is the first report on the relation between the polyanion/PIC stoichiometry and the depiction of the J‐band of the res

ISSN:0025-116X    

DOI:10.1002/macp.1980.021810709

出版商:Hüthig&Wepf Verlag    

年代:1980

数据来源: WILEY

摘要:

AbstractKinetic schemes are solved for polymerization systems involving competition between linear growth and cyclisation by back‐biting to an optional chain unit and/or to the last unit (end‐to‐end ring closure). A fast reaction of a growing centre with an end group may lead to a situation, called here “kinetic enhancement in macrorings”, in which the transient concentration of cyclics formed in polymerization system exceeds their equilibrium concentration. Sometimes, a peculiar kinetics may be observed in which propagation proceeds on linear active macromolecules, but the polymerization leads almost exclusively to the cyclic products. On the other hand, fast propagation due to a high reactivity of monomer may lead to kinetic reduction of macrorings. Several situations are considered with examples taken from cationic polymerization of cyclic acetals and siloxanes (kinetic enhancement) or anionic polymerization of ϵ‐caprolactone (kinetic reduction). Kinetic schemes are numerically solved by computer for some arbitrarily assumed rate constants. This is the first paper of a series aiming to relate the kinetically controlled concentration of macrorings to the polymerization mechanism and the numerical values of the ra

ISSN:0025-116X    

DOI:10.1002/macp.1980.021810710

出版商:Hüthig&Wepf Verlag    

年代:1980

数据来源: WILEY