摘要:

AbstractA plenary lecture should be an introduction into the main topic of the symposium and a review about the state of art. Therefore, in the first part of this presentation different possibilities for the preparation of new polymers are briefly discussed from a chemical point of view. Some selected examples from the literature show how methods of organic chemistry can be utilized for polymer science: new catalytic systems, new monomers, modification of polymers, new poly‐reactions. In the second part, several polyelectrolytes are described: polymers with sec., tert. and quart. N‐atoms in the main chain, block copolymers and block polyampholytes. The third part deals with the problems of rod‐like macromolecules for instance oligo‐ and poly(p‐phenylene)s, poly(p‐phenyleneethynylene)s, aromatic polyimides and a new

ISSN:0258-0322    

DOI:10.1002/masy.19900330103

出版商:Hüthig&Wepf Verlag    

年代:1990

数据来源: WILEY

摘要:

AbstractPolymers of the family of 2‐substituted 2‐oxazolines have the general structure of poly(N‐acylethylenimine), whose hydrophilic/lipophilic properties vary according to the substituent, i.e., the acyl group of the polymer. Of special interest is the polymer of 2‐methyl‐substituted monomer, which has a strong affinity for water. Another useful feature of the 2‐oxazoline family is the fact that its polymerization reaction is quite clean without disturbance by chain transfer and termination. On the basis of the above characteristics, three kinds of novel materials of functional polymers have been explored:1.Non‐ionic polymeric surfactants.2.Non‐ionic hydrogels.3.Block copolymer with silica gel: Organic/inorganic p

ISSN:0258-0322    

DOI:10.1002/masy.19900330104

出版商:Hüthig&Wepf Verlag    

年代:1990

数据来源: WILEY

摘要:

AbstractIn search for the new synthetic methods which may lead to the copolymers of controlled mer sequences, several new carbocyclic and heterocyclic monomer systems such as 1,1‐disubstituted 2‐vinylcyclopropanes, 1‐(p‐anisyl)‐2‐vinylcyclopropanes, substituted 3,4‐dihydro‐2H‐pyrans, substituted 4‐vinyl‐2‐oxetanones and α‐vinyl cyclic sulfones were synthesized and their polymerization behaviors were investigated. And other promising monomer

ISSN:0258-0322    

DOI:10.1002/masy.19900330105

出版商:Hüthig&Wepf Verlag    

年代:1990

数据来源: WILEY

摘要:

AbstractThiosemicarbazide, phosphoric acid and amidoxime derivatives of chitosan were synthesized and their ability for metal ion adsorptions was discussed. Thiosemicarbazide derivative, synthesized by treating chlorodeoxychitosan with ammonium thiocyanate followed by treatment with hydrazine, was considered to have cross‐linked network structure. Phosphoric acid derivative containing both N‐phosphonic acid and phosphoric acid groups was synthesized by cyanoethylation of chitosan using acrylonitrile, followed by treatment with hydroxylamine. These derivatives were found to adsorb effectively infinitesimal concentration (ppb order) of uranyl ion in seawater. Stability constants of some metal ion chitosan chelates were determined. To improve the selectivity in the adsorption of metal ions, a novel method utilizing metal ion as a template was adopted, and the results are discus

ISSN:0258-0322    

DOI:10.1002/masy.19900330106

出版商:Hüthig&Wepf Verlag    

年代:1990

数据来源: WILEY

摘要:

AbstractThe structure and physico‐mechanical properties of polyphosphazene, poly(trimethylvinylsilane) and blends of polyphosphazene with polyethylene were studied. It was shown that these organoelement homopolymers form mesophase structure which can be described as condis‐crystal, and mesophase polymers are effective modifiers when mixed as blends with polyethylene, allowing to make processing more effective and obtain composites with improved mechanical propert

ISSN:0258-0322    

DOI:10.1002/masy.19900330107

出版商:Hüthig&Wepf Verlag    

年代:1990

数据来源: WILEY

摘要:

AbstractThe description of the property and processing advantages of thermotropic liquid‐crystalline main‐chain polymers is followed by the discussion of chemical and physical means how to tailor such macromolecu

ISSN:0258-0322    

DOI:10.1002/masy.19900330108

出版商:Hüthig&Wepf Verlag    

年代:1990

数据来源: WILEY

摘要:

AbstractSynthetic methods of aromatic copolyesters having ordered comonomer sequence are described. In order to obtain a regular sequence copolyester, one first has to prepare a dimeric or trimeric compound with a predesigned sequence via a multistep route and then polycondense it with another difunctional compound. Low reaction temperature is required to avoid the occurrence of undesired interchange reactions that would lead to randomization of the comonomer sequence. Sequentially ordered copolyesters exhibit significant differences in thermal transitions, crystalline properties, and occasionally even in liquid crystallinity when compared with the properties of the corresponding random copolyesters. According to the preliminary results randomization in comonomer sequence of sequentially regular aromatic copolyesters above their melting points is rather rapid.

ISSN:0258-0322    

DOI:10.1002/masy.19900330109

出版商:Hüthig&Wepf Verlag    

年代:1990

数据来源: WILEY

摘要:

AbstractFree‐radical addition polymerization can be carried out using four different processes: mass or bulk, solution, suspension, and emulsion polymerization. Of these four processes, emulsion polymerization is unique because it is a heterogeneous process, in which the polymerization reactions can take place in three different sites: in the continuous aqueous phase, on the surface of growing particles, and within the growing particles. This unique feature of emulsion polymerization offers many possibilities for designing different polymers and latexes: e.g., high‐molecular‐weight polymers, uniform copolymers, copolymers of difficult‐to‐copolymerize monomers, functionalized (surface‐modified) latexes, uniform size latex particles, grafted latexes, and structured latexes having core‐shell, microdomain structures, interpenetrating polymer networks, etc. This paper will describe several aspects of the control of structure in emulsion p

ISSN:0258-0322    

DOI:10.1002/masy.19900330110

出版商:Hüthig&Wepf Verlag    

年代:1990

数据来源: WILEY

摘要:

AbstractThe synthesis of polymethacrylates by a repeated silyl Michael addition reaction (GTP)aallows one to control the molecular weight of the polymer by adjusting the monomer/initator ratio. A small amount of cyclic termination occurs but in general low molecular weight dispersity is obtained. Block polymers can be made by sequential addition of monomer. Functionality present on the ketene acetal portion of the initiator will be on one end of each polymer chain. Star polymers result from crosslinking active polymer with a bismethacrylate. Initiation of bismethacrylate with bisinitiator gives a ladder polymer.

ISSN:0258-0322    

DOI:10.1002/masy.19900330111

出版商:Hüthig&Wepf Verlag    

年代:1990

数据来源: WILEY

摘要:

AbstractCyclopolymerization of dipropargyl derivatives which leads to new conjugated polymers was examined by various transition‐metal catalyst systems. The highly colored polymers with average molecular weights of 10000–47000 were soluble in common organic solvents. Poly(dipropargyl derivatives) which possess polyene structures having cyclic recurring units in the polymer backbone, have been investigated for their physical properties such as solubility, the nature of doping process, electrical conductivity, and oxidation stabil

ISSN:0258-0322    

DOI:10.1002/masy.19900330112

出版商:Hüthig&Wepf Verlag    

年代:1990

数据来源: WILEY