摘要:

AbstractThe polymerization of ethylene carbonate using different metal alkoxides results in poly(oxy‐ethylene‐alt‐ethylene carbonate). Polymers containing low amounts of CO2or pure poly(oxy‐ethylene) are formed with anionic and cationic initiators. Poly(ethylene carbonate) is not accessible from ethylene carbonate by variation of temperatures and concentration. The reason is not the low ceiling temperature, but the positive enthalpy of polymerization. A ΔHp‐value of 125,6 kJ/mol was obtained from calorimetric inve

ISSN:0025-116X    

DOI:10.1002/macp.1990.021910301

出版商:Hüthig&Wepf Verlag    

年代:1990

数据来源: WILEY

摘要:

AbstractCopolymers with intramolecular charge transfer interactions were synthesized by radical copolymerization of ω‐(N‐carbazolyl)alkyl methacrylates (where alkyl is propyl and butyl) with 2‐(methacryloyloxy)ethyl 3,5‐dinitrobenzoate. These copolymers are characterized by a dependence of the electronic absorption, the solubility and the density on the composition. The intramolecular degree of complexation depends on spacer length and exerts a maximum for the spacer with three methylen

ISSN:0025-116X    

DOI:10.1002/macp.1990.021910302

出版商:Hüthig&Wepf Verlag    

年代:1990

数据来源: WILEY

摘要:

AbstractSequential diblock copolymers composed ofL‐ andD‐lactic acid residues were synthesized through a living ring‐opening polymerization ofL‐ andD‐lactide initiated by aluminium tris(2‐propanolate). The composition of the block copolymers was varied by changing the reaction conditions and monomer over initiator ratio and confirmed by1H NMR analysis, molecular weight determination and optical rotation measurements. Molecular weights ranged from 1,3 to 2,0 · 104with 1,2

ISSN:0025-116X    

DOI:10.1002/macp.1990.021910303

出版商:Hüthig&Wepf Verlag    

年代:1990

数据来源: WILEY

摘要:

AbstractPoly(acrylic ester)s3a–fand4a–g, containing 4′‐cyano‐4‐biphenylyloxy mesogenic groups coordinating to Pt(II) ions with various contents, were synthesized by ligand exchange reaction of poly(acrylic ester)s1and2with dichlorobis(benzonitrile)platinum (II). The effect of Pt(II) coordination of the mesogen on the thermotropic liquid‐crystalline behavior was examined by DSC, X‐ray diffraction, and polarizing microscopy. For polymers1,3a–cwith a contentxof 4′‐cyano‐4‐biphenylyloxy mesogen coordinating to the Pt(II) ion less than 24 mol‐%, a nematic mesophase was observed betweenTgandTc. For polymers2,4a–ewithx<20 mol‐%, a smectic mesophase was found betweenTgandTc. On the other hand, polymers3d–fand4 fandgwith a high amount of mesogenic groups coordinating to the Pt(II) ion do not form mesophases due to the cross‐linked structure resulting from the coordinati

ISSN:0025-116X    

DOI:10.1002/macp.1990.021910304

出版商:Hüthig&Wepf Verlag    

年代:1990

数据来源: WILEY

摘要:

AbstractAn imidazolyl ring was introduced into the side chain of poly(3‐chlorocarbonylpropylmethyl‐siloxane) (4) by esterification with 4(5)‐hydroxymethylimidazole (1), the imino group being protected during esterification by the 2‐nitrobenzyl group which can be easily cleaved by UV light irradiation without attacking the main chain. The photolytic cleavage of the 2‐nitrobenzyl group was completed with a yield of ≈ 100% after 2 h without any remarkable side reaction. The polyorganosiloxanes (6), with a high content of imidazolyl groups in the side chain, are slightly soluble in hot DMSO and DMF. From this fact, in addition to the result of the measurement ofTg, it is suggested that very strong intermolecular hydrogen bonds ar

ISSN:0025-116X    

DOI:10.1002/macp.1990.021910305

出版商:Hüthig&Wepf Verlag    

年代:1990

数据来源: WILEY

摘要:

AbstractFour enol esters with a styrene skeleton (3a–d) were synthesized in two steps from commercial products and polymerized or copolymerized with styrene as a comonomer. The polymers and copolymers (7and8) were characterized. They are stable up to 140°C and lose acetic acid upon heating. Chemical modifications, such as nucleophilic substitutions with cyanide ions or nucleophilic addition of butyllithium, were studi

ISSN:0025-116X    

DOI:10.1002/macp.1990.021910306

出版商:Hüthig&Wepf Verlag    

年代:1990

数据来源: WILEY

摘要:

AbstractNew amphiphilic poly(vinylsaccharide)s (poly(7) and poly(8)) were synthesized. Various alkylamino substituted mono‐ and disaccharides3and5were obtained by reductive amination of reducing mono‐ and disaccharides with alkylamines. The reaction of these monofunctionalized sugar derivates with 2‐isocyanatoethyl methacrylate (2) leads to well‐defined monomers (7and8) of the urea type. The monomers were polymerized in aqueous solution to high‐molecular‐weight polymers, using the redox initiator system (NH4)2S2O8/Na2S2O5. The influence of structural variations by changing the hydrophilic sugar moiety or the lipophilic alkyl part was studied by viscometry, light scattering and measurements of the surf

ISSN:0025-116X    

DOI:10.1002/macp.1990.021910307

出版商:Hüthig&Wepf Verlag    

年代:1990

数据来源: WILEY

摘要:

AbstractPolymeric prodrugs of 5‐aminosalicylic acid, a drug used for the treatment of inflammatory bowel diseases such as ulcerative colitis and Crohn's disease, were synthesized and characterized. The active drug 5‐aminosalicylic acid was first coupled to a spacer group via an azo bond. All spacer‐pharmacon systems prepared have a terminal primary amino function, which by nucleophilic reaction was coupled under mild conditions to poly(methyl vinyl ether‐co‐maleic anhydride) (5) and poly(1‐vinyl‐2‐pyrrolidon‐co‐maleic anhydride) (6), without crosslinking. The polymeric prodrugs were characterized by UV and NMR. All polymer derivatives are insoluble in water at acidic pH‐range, but dissolve slowly in neutral or s

ISSN:0025-116X    

DOI:10.1002/macp.1990.021910308

出版商:Hüthig&Wepf Verlag    

年代:1990

数据来源: WILEY

摘要:

AbstractPoly(ester‐imide)s with a regular sequence of aliphatic spacers and aromatic imide mesogens were prepared in two ways. Either aliphatic α,ω‐diacids were condensed with an acetylated diphenol derived from 4‐hydroxyphthalic acid and 4‐aminophenol, or aliphatic α,ω‐diacid dichlorides were condensed with the silylated diphenol. The resulting poly(ester‐imide)s were characterized by elemental analyses, viscosity measurements, microscopy under polarized light, DSC‐ and WAXS measurements. All poly(ester‐imide)s are crystalline materials with a layered supermolecular structure in the solid state. Above the melting point a nematic mesophase exists over a broad temperature range. A pronounced odd‐even effect was found for the temperature of isotropization, but not f

ISSN:0025-116X    

DOI:10.1002/macp.1990.021910309

出版商:Hüthig&Wepf Verlag    

年代:1990

数据来源: WILEY

摘要:

AbstractNovel 2‐substituted 9‐methacryloyloxy‐8,8‐dimethyl‐1,4,6‐trioxaspiro[4,4]nonanes3a–ewere synthesized byO‐acylation of the corresponding 9‐hydroxyspiroorthoesters2a–ewith methacrylic acid. Its radical homopolymerization in solution results in film‐forming, soluble polymers with intact spiroorthoester groups, which can be crosslinked by cationic ring‐opening reaction. On the other hand, insoluble polymers are formed by radical polymerization of these methacrylic spiroorthoesters3a–ein bulk. Crosslinking is traced back to a radical ring‐opening reaction as a consequence of a chain transfer reaction at the spiro

ISSN:0025-116X    

DOI:10.1002/macp.1990.021910310

出版商:Hüthig&Wepf Verlag    

年代:1990

数据来源: WILEY