摘要:

AbstractAn amorphous copolyester ofL‐lactic acid (LA) andDL‐hydroxyisocaproic acid (HICA) with a number‐average molecular weight (Mn) of 1600–4800 was synthesized by direct copolycondensation in the absence of catalysts, in order to develop a biodegradable carrier for drug delivery systems. Thein vivodegradation pattern was changed into an S‐type from a parabolic‐type with an increase in molecular weight of copolyester. A luteinizing hormone‐releasing hormone agonist, des‐Gly10‐[D‐Leu6]‐LH‐RH ethylamide, was incorporated into a fine cylindrical copolyester formulation by the so‐called melt‐pressing technique. When the S‐type degradable and releasable copoly(LH/HICA) (70/30 mol‐%) formulations withMn= 2200 were implanted subcutaneously in the back of rats, the most reasonable serum drug level was observed during the first 15 weeks period, keeping cons

ISSN:0025-116X    

DOI:10.1002/macp.1990.021910401

出版商:Hüthig&Wepf Verlag    

年代:1990

数据来源: WILEY

摘要:

AbstractDifferent methods of preparation of monodisperse diols were reviewed and a new synthesis of perfectly monodisperse macrodiol5is described, obtained by radical telomerization of monoester3 b(prepared by esterification of 10‐undecenoic acid (3 a) with 1,6‐hexanediol) with dithiol4. Macrodiol5was used to obtain prepolymers by reaction with aromatic or aliphatic diisocyanates (6and7). Finally, these prepolymers were extended by 1,4‐butanediol and led to polyurethanes. All the above products were analyzed by GPC,1H NMR, and the resulting polyurethanes were tested mechanically. The study shows that monodisperse diols lead to better mechanical properties of the polyurethane than those obtained from polydisperse diols with equal molecular w

ISSN:0025-116X    

DOI:10.1002/macp.1990.021910402

出版商:Hüthig&Wepf Verlag    

年代:1990

数据来源: WILEY

摘要:

Abstract1,3‐Bis[3‐(4‐ethynylbenzoylamino)propyl]hexamethyldisiloxane (3) was prepared and characterized. The flexible central unit of this product enables the easy and through polymerization of ethynyl groups at moderate temperature (220°C). The structure of the product resulting from the thermal polymerization of this diamide could not be elucidated so far. The product has a rather highTg(260°C) and keeps it properties up to 250°C. On heating for a prolonged period of time at this temperature or at a higher one, the amide bond is cleaved, as evidenced by TG and F

ISSN:0025-116X    

DOI:10.1002/macp.1990.021910403

出版商:Hüthig&Wepf Verlag    

年代:1990

数据来源: WILEY

摘要:

AbstractIn heat‐treated polyamide 6 and polyamide 6,6 fibres UV/VIS‐active chromophores are found, which originate from two different sources: one type of chromophore (structured UV spectrum) arises during polycondensation and the spinning of the fibres (molten phase), the other (nonstructured UV spectrum) occurs as a result of a thermo‐oxidation is based on conjugated oligoenimies , as is shown by a combination of UV/VIS spectroscopy and fluorescence excitation and emission spectroscopy with chemical analysis. The concentration of the various oligoenimine species depends upon the temperature and duration of the thermooxidation. For a temperature of 160°C and a duration of 2 hours, for example, the following oligoenimine concentrations were found (UV spectroscopy with computer‐aided evaluation): fori= 0: 44;i= 1: 13;i= 2: 4;i= 3: 1;i= 4: 0,3 (values expressed in

ISSN:0025-116X    

DOI:10.1002/macp.1990.021910404

出版商:Hüthig&Wepf Verlag    

年代:1990

数据来源: WILEY

摘要:

AbstractThe free‐radical copolymerization of styrene and methyl α‐cyanocinnamate was studied. The copolymers were investigated by means of NMR spectroscopy. From the assignment of the signals both in1H and13C NMR spectra it follows that not only head‐to‐tail but also head‐to‐head coupling of styrene and methyl α‐cyanocinnamate monomeric units occurs in the copolymers. The composition data of the copolymers can be described by the penultimate model as seen from the linear distribution of the data points in a modified Kelen‐Tü

ISSN:0025-116X    

DOI:10.1002/macp.1990.021910405

出版商:Hüthig&Wepf Verlag    

年代:1990

数据来源: WILEY

摘要:

AbstractA high‐molecular‐weight poly(leuco base) (Mn= 11000–18000) was obtained by addition polymerization ofN,N′‐dibenzyl‐4,4′‐methylenedianiline (2) and 2,2‐bis[4‐(2,3‐epoxypropoxy)‐phenyl]propane (diglycidyl ether of Bisphenol A) (1).The oxidation of this addition polymer with chloroanil, iodine, bromine, chlorine or antimony pentachloride results in polymeric dyes (absorption at λ = 620 nm) containing units of the “Michler Hydrolblau” type. The dielectric behavior in the frequency range 102Hz up to 107Hz shows a dependence of the conductivity on the temperature. Polymer4cexhibits a conductivity of σ = 6 ·

ISSN:0025-116X    

DOI:10.1002/macp.1990.021910406

出版商:Hüthig&Wepf Verlag    

年代:1990

数据来源: WILEY

摘要:

AbstractMany samples of a semiflexible thermotropic polyester were synthesized by low‐temperature solution polycondensation of 2‐methylhydroquinone (5) and 4,4′‐sebacoyldioxydibenzoyl chloride (4) and characterized by polarizing microscopy, differential scanning calorimetry and X‐ray diffraction. The influence of some experimental parameters, such as polymerization temperature, tertiary amine and monomer concentration, on polymer yields and molecular weights was studied. Thermal behaviour, in terms of thermal stability of the polyesters and range of mesophase stability, was investigated as a function of the molecular weight of the samples. Thermal treatments and X‐ray diffraction at different temperatures were performed to achieve a better understanding of the transitions characteristic of this polyester. All the samples give a nematic phase; on as‐polymerized specimens a solid‐solid transition wa

ISSN:0025-116X    

DOI:10.1002/macp.1990.021910407

出版商:Hüthig&Wepf Verlag    

年代:1990

数据来源: WILEY

摘要:

AbstractCrosslinking reactions of prepolymers of the polyphenylene type carrying acetyl end‐groups, based on 4,4′‐oxydiacetophenone and acetophenone (FPP‐1), or 4‐acetylacetophenone and 4‐(4‐acetylphenoxy)phenyl‐o‐carborane (FPP‐2), by means of 20–80 wt.‐% of 1,2‐bis[hydrido‐(dimethyl)siloxymethyl]‐o‐carborane (1) were investigated. It was found that the prepolymer FPP‐1 is easily crosslinked in the presence of 30 wt.‐% of1at 300°

ISSN:0025-116X    

DOI:10.1002/macp.1990.021910408

出版商:Hüthig&Wepf Verlag    

年代:1990

数据来源: WILEY

摘要:

AbstractCarborane‐containing oligoorganosilazanes (COS) (20 to 60 wt.‐%) prepared by coammonolysis of (o‐carboranylmethoxy)dichloro(phenyl)silane and trichloro(phenyl)silane (COS1), or 1‐chloro‐1‐phenyl‐1‐sila‐2,7‐dioxa‐4,5‐(1,2‐carborano)cycloheptane and dichloro(dimethyl)‐silane (COS2), were used to crosslink polyphenylene type prepolymers on the basis of 4,4′‐oxydiacetophenone and acetophenone (FPP‐1). This allowed the reduction of the crosslinking temperature of FPP‐1 by 100–150°C, retaining a high heat resistance of the final crosslinked polymer. Octamethylcyclotetrasilazane (15 wt.‐%) was used to crosslink the carborane‐containing prepolymers on the basis of 1,2‐bis[4‐(4‐acetylphenoxy)phenyl]‐o‐carborane and acetophenone (FPP‐2) and 1,2‐bis(4‐acetylbenzyl)‐o‐carborane and acetophenone (FPP‐3). At

ISSN:0025-116X    

DOI:10.1002/macp.1990.021910409

出版商:Hüthig&Wepf Verlag    

年代:1990

数据来源: WILEY

摘要:

AbstractPoly(thio‐1,4‐phenylene)s (PPS)5a–dwith reactive end groups like carboxyl, nitro, cyano and aldehyde groups were synthesized under high as well as atmospheric pressure. Carboxyl terminated telechelics5awere used as starting materials for the synthesis of poly(thio‐1,4‐phenylene)‐block‐polyamides. Semicrystalline and amorphous polyamides like Nylon 6 and Trogamide® served as coblocks. The formation of block copolymers was approved by the solubility behavior, the NMR and IR spectra as well as high temperature GPC. The thermal stability increases with the fraction of PPS. By DSC, phase separation of the block copolymers was observed at certain compositions and mol

ISSN:0025-116X    

DOI:10.1002/macp.1990.021910410

出版商:Hüthig&Wepf Verlag    

年代:1990

数据来源: WILEY