摘要:

Abstract“Criss‐cross”‐cycloaddition of 4,4′‐diisocyanatodiphenyl ether and 4‐methoxybenzaldazine was used to synthesize α,ω‐diisocyanato telechelics of molecular weights between 1 600 and 3 900. These precursors were reacted with different α,ω‐dihydroxy functionalized aliphatic polyethers to produce segmented block copolymers in which the precursors obtained by cycloaddition reaction provide hard segment domains embedded in a polyether soft segment matrix. The resulting materials were soluble in common organic solvents such as tetrahydrofuran and chloroform and were characterized by spectroscopic techniques (1H‐,13C NMR, IR spectroscopy) as well as gel permeation chromatography (GPC) for molar mass determination. The block copolymers were molded in a hot stage press, and the resulting samples were characterized by differential scanning calorimetry (DSC), dynamic mechanical thermal analysis (DMTA) and stress‐strain measurement. The materials with a hard segment fraction below 0.36 and a molecular weight aboveM̄n= 90 000 were elastomers with ultim

ISSN:1022-1352    

DOI:10.1002/macp.1997.021980111

出版商:Hüthig&Wepf Verlag    

年代:1997

数据来源: WILEY

摘要:

AbstractWell defined graft copolymers have been synthesized by a nitroxide‐mediated “living” free radical process using pre‐formed macromonomers. Analysis of the graft systems revealed that the macromonomer was efficiently incorporated into the polymeric backbone to give block copolymers of controlled molecular weight and narrow polydispersities. An added benefit of the “living” free radical process is that macromonomers, such as polylactide or polycaprolactone, which contain reactive functional groups can be used to form novel graft systems using this approach. Functionalized monomers or polymeric initiators were also used in the copolymerization mixture to give graft systems with a variety of functional groups attached to t

ISSN:1022-1352    

DOI:10.1002/macp.1997.021980112

出版商:Hüthig&Wepf Verlag    

年代:1997

数据来源: WILEY

摘要:

AbstractThermal and mesogenic properties of semirigid polyamides composed of one benzene ring with a kinked linkage and various aliphatic chains in the repeating unit, which are derived from three 1,3‐diaminobenzenes and aliphatic dicarboxylic acids, were examined. Only two polyamides with a long aliphatic chain (C18H36), based on 4‐methyl‐ and 2,4,6‐trimethyl‐1,3‐diaminobenzenes, form mesophases although the polymers exert nontraditional mesogenic units. Formation of the mesophase in the latter case depends on the inherent viscosity, i.e., polymers with lower inherent viscosity (⩽1,47 dL/g) form a layered structure by intermolecular interaction via hydrogen bonding of the

ISSN:1022-1352    

DOI:10.1002/macp.1997.021980113

出版商:Hüthig&Wepf Verlag    

年代:1997

数据来源: WILEY

摘要:

AbstractThe formation of polyelectrolyte complexes (PEC) between linear or crosslinked poly[4‐(but‐3‐en‐1‐ynyl)‐1‐methylpiperidin‐4‐ol] and linear as well as crosslinked poly(acrylic acid) and poly(methacrylic acid) was studied by potentiometric, conductimetric, turbidimetric, viscometric and volumetric methods in aqueous solution. The composition of PEC particles depends on the conformational state of the interacting macromolecules. The destruction of PEC particles into the individual components takes place at an ionic strength μ>1 × 10−2mol/L. The addition of organic solvents causes the conformational transition of PEC particles from the compact structure to an extended one. The sorption of linear polyelectrolytes by networks is accompanied by the shrinking of the polyelectrolyte gels. The kinetics of sorption increases with increasing temperature, ionic strength of the solution and ionization degree. The destruction of PEC consisting of oppositely charged linear and crosslinked polyelectrolytes takes place at high ionic strength of the external solution. The completeness of interpolyelectrolyte reactions with participating of linear and crosslinked poly[4‐(but‐3‐en‐1‐ynyl)‐1‐methylpiperidin‐4‐ol] was detected by the disappearance of the Bohlman band at 2 800 cm−1. The kinetics of sorption of linear polyelectrolytes by crosslinked polyelectrolytes as well as of the competition reaction which is accompanied by the destruction of PEC composed of oppositely charged linear and cros

ISSN:1022-1352    

DOI:10.1002/macp.1997.021980114

出版商:Hüthig&Wepf Verlag    

年代:1997

数据来源: WILEY

摘要:

AbstractAminocarboranesnido‐7‐NH3+‐(7‐CB10H12)−andcloso‐1‐NH3+‐(CB11H11)−were copolymerized with α,ω‐dihalogenoalkanes to high‐molecular‐weight alternating copolymers. Thenido‐compound copolymer was crosslinked by means of sandwiching two open cages with CoIIIion yielding bis(monocarbollide)‐cobaltate(III) units as the new type knot points. Metallacarboranes, 1,1′‐diaminobis(monocarbollide)nickelate(IV) and two bridged bis(dicarbollide)cobaltates(III) (8,8′‐μ‐imino‐ and 8,8′‐μ‐oxyimino‐), have provided hemipolymers of molecular weight up to a few thousands in the same type of copolymerization. A new methacrylic‐type monomer was prepared by reaction of glycidyl methacrylate with 8,8′‐(μ‐imino)‐(1,2‐C2B9H10)‐3‐CoIIIand copolymerized with

ISSN:1022-1352    

DOI:10.1002/macp.1997.021980115

出版商:Hüthig&Wepf Verlag    

年代:1997

数据来源: WILEY

摘要:

AbstractA chiral poly(3‐substituted isobutylD‐aspartate)12was synthesized by polymerization of the chiral β‐lactam11derived fromD‐glyceraldehyde. The new polyamide was characterized by elemental analyses, and infrared,1H‐ and13C nuclear magnetic resonance spectroscopies. The molecular weight was estimated as 543 000 and 230 000 on the basis of viscosimetric measurements and gel‐permeation chromatography, respectively. Polyamide12is soluble in a variety of organic solvents includin

ISSN:1022-1352    

DOI:10.1002/macp.1997.021980116

出版商:Hüthig&Wepf Verlag    

年代:1997

数据来源: WILEY