摘要:

AbstractPoly(ε‐caprolactone) was found to form inclusion complexes with α‐cyclodextrin to give crystalline compounds. The complexes are stoichiometric one‐to‐one (cyclodextrin: monomer unit) compounds. The yields of the complexes decreased with increasing the molecular weight of the polymer. They were characterized by IR,1H NMR,13C CP/MAS NMR, and X‐ray diffraction. The inclusion modes ar

ISSN:1022-1336    

DOI:10.1002/marc.1997.030180701

出版商:Hüthig&Wepf Verlag    

年代:1997

数据来源: WILEY

摘要:

AbstractThe spectral changes of Crystal Ponceau 6R and Ponceau 4R induced by the interaction with polycations havingN,N‐dimethyl‐2‐hydroxypropane‐1,3‐diylammonium chloride units in the main chain were followed. The stoichiometry of the polycation‐dye complex related to the dye structure was elaborated by UV‐VIS spectrophotometry and viscosimetric measurements. Formation of a tricomponent complex between the polycation/dye complex and poly(sodium acrylate) was

ISSN:1022-1336    

DOI:10.1002/marc.1997.030180702

出版商:Hüthig&Wepf Verlag    

年代:1997

数据来源: WILEY

摘要:

AbstractGraft copolymers of poly(ethylene glycol) (PEG) on a chitosan backbone (PEG‐g‐chitosan) have been synthesized and their aqueous solution properties were investigated. At pH 6.5 the graft copolymers are 100% soluble, while chitosan phase separates from solution at those conditions. These interesting graft copolymers may be especially suitable as carriers for delivery of anionic drugs, such as proteins, glycosaminoglycans, and DNA plasmids or oligonucleoti

ISSN:1022-1336    

DOI:10.1002/marc.1997.030180703

出版商:Hüthig&Wepf Verlag    

年代:1997

数据来源: WILEY

摘要:

AbstractThermosetting cholesteric oligocarbonates were prepared by polycondensation of mesogenic diphenols such as 4,4′‐dihydroxybiphenyl (DHB) or hydroquinone 4‐hydroxy‐benzoate (HQHB; system. name: 4‐hydroxyphenyl 4‐hydroxybenzoate) with methylhy‐droquinone and isosorbide. Trichloromethyl chloroformate served as condensing agent and propargyl alcohol (system. name of propargyl: 2‐propynyl), 4‐propargyloxybenzoyl chloride or 6‐propargyloxy‐2‐napthoyl chloride served as chain stoppers. Most oligocar‐bonates form a cholesteric phase over a broad temperature range. Depending on the mole fraction of isosorbide these oligocarbonates form Grandjean textures when sh

ISSN:1022-1336    

DOI:10.1002/marc.1997.030180704

出版商:Hüthig&Wepf Verlag    

年代:1997

数据来源: WILEY

摘要:

AbstractThe interfacial tension between phase separated polymer solutions increases pronouncedly upon the addition of small amounts of incompatible polymers. This feature is demonstrated by means of measurements with solutions of polystyrene in cyclohexane and the following additives: poly(styrene‐block‐dimethylsiloxane), polyisobutylene and polydimethylsiloxane. Theoretical considerations based on a correlation between the lengths of tie lines and the corresponding interfacial tension corroborate this find

ISSN:1022-1336    

DOI:10.1002/marc.1997.030180705

出版商:Hüthig&Wepf Verlag    

年代:1997

数据来源: WILEY

摘要:

AbstractBlends of poly(ε‐caprolactone) as the matrix material and 1,2,4, or 8 wt.‐% of a poly‐peptide were prepared by dissolution in a cosolvent and coprecipitation into cold methanol. A low‐and a high‐molecular‐weight poly(γ‐benzylL‐glutamate), a poly(γ‐methylL‐glutamate) and a poly(D,L‐phenylalanine) were used as reinforcing components and compared with a liquid‐crystalline (LC) polyester derived from a double‐substituted terephthalic acid. Films of all blends were subjected to stress‐strain measurements. A weak reinforcing effect was found for the poly(γ‐benzylL‐glutamate)s, a somewhat stronger influence for the other polypeptides and the str

ISSN:1022-1336    

DOI:10.1002/marc.1997.030180706

出版商:Hüthig&Wepf Verlag    

年代:1997

数据来源: WILEY

摘要:

AbstractEnzymatic ring‐opening polymerization of a 6‐membered cyclic carbonate, 1,3‐dioxan‐2‐one, was investigated by using lipase as catalyst in bulk. Supported lipase derived fromCandida antarcticacatalyzed the polymerization to give the corresponding aliphatic polycarbonate. Unchanged monomer was recovered in the absence of the enzyme or using an inactivated enzyme, indicating that the present polymerization proceeds through enzymatic

ISSN:1022-1336    

DOI:10.1002/marc.1997.030180707

出版商:Hüthig&Wepf Verlag    

年代:1997

数据来源: WILEY

摘要:

AbstractPropene, 1‐butene and 1‐hexene polymerization was conducted with a mixture ofrac‐ andmeso‐[dimethylsilylenebis((2,3,5‐tetramethyl‐cyclopentadienyl))]zirconium dichloride (Me2Si(2,3,5‐Me3Cp)2ZrCl2) (1) combined with methylaluminoxane (MAO), triethylaluminium (AlEt3)/triphenylcarbenium tetrakis(pentafluorophenyl)borate (Ph3CB(C6F5)4) (2) and triisobutylaluminium (AliBu3)/Ph3CB(C6F5)4, respectively, as co‐catalyst systems. The ratios of polymerization ratesRp(rac)/Rp(meso) were changed with the combined cocatalysts. It was found that in the case of using trialkylaluminium/2as co‐catalystRp(rac)/Rp(meso) is lower than when using MAO in any kind of α‐o

ISSN:1022-1336    

DOI:10.1002/marc.1997.030180708

出版商:Hüthig&Wepf Verlag    

年代:1997

数据来源: WILEY

摘要:

AbstractExtrusion rheometry experiments with a commercial thermotropic liquid crystalline copolyester show concave Bagley plots and convex pressure profiles. A loss of the orientation produced at the entrance of the capillary and the slit can explain these non‐linearities. Assuming that the order parameter,S, relaxes exponentially with time, the Doi‐Edwards model for the shear flow of rod‐like polymers is used to adjust experimental

ISSN:1022-1336    

DOI:10.1002/marc.1997.030180709

出版商:Hüthig&Wepf Verlag    

年代:1997

数据来源: WILEY

摘要:

AbstractA new theoretical formula, used for the determination of the chemical composition distribution of copolymers, is proposed in this paper. The composition distribution of styrene in chlorinated butyl rubber/polystyrene comb graft copolymer was obtained by gel permeation chromatography utilising a combination of refractive index and ultraviolet detection. It is a more convenient and time‐saving method for the characterization of the molecular structure parameters of a copolymer compared to the conventional experimental metho

ISSN:1022-1336    

DOI:10.1002/marc.1997.030180710

出版商:Hüthig&Wepf Verlag    

年代:1997

数据来源: WILEY