摘要:

AbstractFive different completely aromatic, ordered poly(ester‐amide)s6a — ewere prepared from diphenols5and 4,4′‐carbonyliminodibenzoyl dichloride (3). This bifunctional “amide‐acid chloride” was synthesized in two steps by oxidation of 4,4′‐dimethylbenzanilide (1) with permanganate under neutral conditions and subsequent reaction with thionyl chloride. The polymers obtained were characterized by IR spectroscopy and viscosity measurements. Their physical properties like density, solubility, and thermal behaviour

ISSN:0025-116X    

DOI:10.1002/macp.1986.021870101

出版商:Hüthig&Wepf Verlag    

年代:1986

数据来源: WILEY

摘要:

AbstractPolymers with tertiary amino groups were obtained by reaction of chloromethylated polystyrene (CMPS) with 3‐alkylaminopropionitriles (2a — e). The resulting polymers3a — ewere characterized by elemental analyses, IR and1H NMR spectra. Kinetic investigation showed that the reaction is characterized by two rate constants, the rate change taking place at a conversion of 45–50%. Viscosimetric studies of the hydrochlorides of polymers3a — ein water and methanol showed that they behave as polyelectrolytes only in methanol. The abnormal behaviour of water solutions was explained by hydrolysis reaction. To prove the conclusions on the molecular structures of3a — eand the reactivity of CMPS, a study of the reaction of benzyl chloride with the same amines wa

ISSN:0025-116X    

DOI:10.1002/macp.1986.021870102

出版商:Hüthig&Wepf Verlag    

年代:1986

数据来源: WILEY

摘要:

AbstractThis paper presents results of the studies on the mechanism of initiation, propagation and chain transfer reactions in the recently found polymerization of 1,4‐ and/or 1,3‐divinylbenzene (DVB), initiated with lithium diisopropylamide/diisopropylamine. Initiation was confirmed to take place by addition reaction of the alkylamino group to the DVB molecule. The population of the triad tacticity of the soluble poly(DVB) suggested the steric course of the polymerization to proceed according to Bernoullian statistics with respect to the diad placements,mandr. The chain transfer reaction was found to take place via the free amine, the chain transfer reactivity of a primary amine being higher than that of a secondary amine. Comparative studies on the reactivity and selectivity of sodium diisopropylamide toward styrene and DVB were also carried out with respect to lithium diisopropylamide as refere

ISSN:0025-116X    

DOI:10.1002/macp.1986.021870103

出版商:Hüthig&Wepf Verlag    

年代:1986

数据来源: WILEY

摘要:

AbstractSome features of the cationic polymerization of hexamethylcyclotrisiloxane (D3) and octamethylcyclotetrasiloxane (D4) in methylene chloride in the presence of a strong protonic acid (CF3SO3H) were compared. The polymerizations of both these monomers show many similarities, which are taken as evidence for analogies in their mechanisms. In particular, in both cases the reaction is affected by the addition of a small amount of water. The role of water is interpreted in terms of its direct participation in some elementary reactions of the process. The addition of water affects also the state of hydrogen bonding association in the system. Some experimental results together with comments concerning the mechanism of ring formation in the polymerization system are included.

ISSN:0025-116X    

DOI:10.1002/macp.1986.021870104

出版商:Hüthig&Wepf Verlag    

年代:1986

数据来源: WILEY

摘要:

AbstractA variety of axially dissymmetric diphenylylene diamines1a — 1fwere synthesized and evaluated as chiral auxiliaries for the polymerization of triphenylmethyl methacrylate with organolithium compounds such as butyllithium and lithium (±)‐N‐(1‐phenylethyl)anilide in toluene at −78°C. The catalysts containing an optically active biphenylylene derivative of tetramethyl‐ethylenediamine (1e) were found to be particularly useful for the preparation of optically active poly(triphenylmethyl methacrylate) (PTrMA). The catalysts afforded tetrahydrofuran (THF)‐soluble polymers in high yields and the polymers showed large optical rotations arising from a one‐handed helical conformation of a polymer chain. (+)‐ and (‐)‐PTrMAs were obtained by using (S)‐1eand (R)‐1e, respectively. The poly(methyl methacrylate)s derived from these PTrMAs were almost completely isotactic, but showed negligible optical rotations. The other catalysts produced mainly polymers insoluble in organic solvents; the small amounts of THF‐soluble materials showed

ISSN:0025-116X    

DOI:10.1002/macp.1986.021870105

出版商:Hüthig&Wepf Verlag    

年代:1986

数据来源: WILEY

摘要:

AbstractThe sequential block copolymerization of diphenylmethyl methacrylate (DMA) and trityl methacrylate (TrMA), initiated by diphenyl methyl lithium in THF at ‐78°C followed by hydrolysis and methylation with diazomethane, leads to the formation of an isotacticsyndiotactic stereoblock poly(methylmethacrylate) (PMMA) of narrow molecular weight and block length distribution. Complete conversion of DMA is shown to be essential, since the presence of small quantities of this monomer during the polymerization of TrMA significantly lowers the isotactic content of this block. Polymerization times of at least 12 h were found to be necessary for complete polymerization of the Tr

ISSN:0025-116X    

DOI:10.1002/macp.1986.021870106

出版商:Hüthig&Wepf Verlag    

年代:1986

数据来源: WILEY

摘要:

AbstractThe zwitterionic copolymerization of 2‐methyl‐2‐oxazoline (MOX) as nucleophilic monomer with β‐butyrolactone (BUL) as electrophilic monomer was investigated in bulk and in solution (CH3CN) at 45°C. The copolymer composition was around 1,5/1,0 (BUL/MOX) as was established by1H NMR.1H and13C NMR spectroscopy were used to identify the copolymers. The IR spectroscopy supported the NMR results. On the other hand, the copolymers behave as polyelectrolytes, according to viscosity determinations. A copolymerization mechanism through a zwitterion species is

ISSN:0025-116X    

DOI:10.1002/macp.1986.021870107

出版商:Hüthig&Wepf Verlag    

年代:1986

数据来源: WILEY

摘要:

AbstractThe four fragments of the terminal inverted repeating units of macronuclear DNA from hypotrichous ciliates d(A4C4), d(C4A4C4), d(A4C4A4C4) and d(C4A4C4A4C4) were synthesized in preparative amounts (300 mg) by block condensation using the phosphotriester procedure. At first, partially protected nucleosides and mononucleotides were condensed to dimeric blocks using 2,4,6‐triisopropylbenzenesulfonyl chloride andN‐methylimidazole. Longer blocks were synthesized from the dimers using 2,4,6‐triisopropylbenzenesulfonyl chloride and tetrazole. After each condensation the reaction mixture was fractionated using a silica gel column and a step gradient. After synthesis, cleavage of the protecting groups and gelchromatographical separation, d(A4C4) and d(A4C4A4C4) were obtained already as pure substances. On the other hand, having cleaved the protecting groups partially or totally, d(C4A4C4) and d(C4A4C4A4C4) were separated first on QAE‐Sephadex by a salt gradient in 7 M urea. The remaining impurities were removed by preparative reversed phase HPLC. Sequence as well as purity of the DNA fragments were proved by partial enzymatic degradation and two‐dimensional chromatography of the hydrolysates (fin

ISSN:0025-116X    

DOI:10.1002/macp.1986.021870108

出版商:Hüthig&Wepf Verlag    

年代:1986

数据来源: WILEY

摘要:

AbstractPolymerizable crown ethers,N‐acryloyl‐ andN‐methacryloyl‐N‐ethylaminomethyl crown ethers (4a,band5a, b), were prepared fromN‐ethylaminomethyl crown ethers (1and2). Their polymerization and copolymerization with styrene afforded the new poly(crown ether)s(6), in which the crown rings are attached to the polymer chain by an am

ISSN:0025-116X    

DOI:10.1002/macp.1986.021870109

出版商:Hüthig&Wepf Verlag    

年代:1986

数据来源: WILEY

摘要:

AbstractCopolymers and alternating block copolymers were prepared both containing a liquid crystalline (LC) polyether segment, based on 4,4′‐biphenyldiol(3)and 1,5‐dibromopentane(2), and a thermoplastic segment, deriving from an aromatic poly(ether sulfone) (PSU)(1). The alternating block copolymer was prepared by the phase transfer catalyzed (PTC) polyetherification of mesogenic α,ω‐bis(5‐bromopentoxy)polyether(5)with α,ω‐bis(hydroxyphenyl)PSU(1). Copolymers containing mesogenic segments were prepared utilizing α,ω‐bis(hydroxyphenyl)‐PSU as another diphenol in the PTC polyetherification of5with2and3. The thermal behavior, as characterized by differential scanning calorimetry (DSC), revealed phase separation for all prepared copolymers as well as liquid crystalline behavior down to a content of mesogenic units deriving from5as low as 30 wt.‐%. Optical polarization microscopy, however, revealed significant differences in textures of the copolymers with the textures observed for homopolymer5. Textures of a5/PSU blend clearl

ISSN:0025-116X    

DOI:10.1002/macp.1986.021870110

出版商:Hüthig&Wepf Verlag    

年代:1986

数据来源: WILEY