摘要:

AbstractStudies were made on the synthesis of halide‐substituted poly(phthalidylidenearylene)s by Friedel‐Crafts polycondensations of 3‐aryl‐3‐chlorophthalides containing substituents in 4‐position of the phthalide cycle. As follows from the C13NMR spectra, those monomers can afford polymers containing two types of isomeric units substituted in 4‐ or 7‐position. The possible routes of formation of the isomeric units are analyzed and a scheme is suggested for the monomer rearrangement in the synthetic course. The polymers containing those two types of units were shown to be highly thermostable and to contain about 30% of a cr

ISSN:0025-116X    

DOI:10.1002/macp.1990.021910701

出版商:Hüthig&Wepf Verlag    

年代:1990

数据来源: WILEY

摘要:

AbstractCatalysts obtained from TiCl4and ball‐milled Mg(OEt)2in the presence of a halide compound (dichloroethane, chlorobenzene or dichlorobenzene) and/or an internal donor (ethyl benzoate or diisobutyl phthalate) were prepared for propene polymerization. The composition of the catalysts was analyzed by IR, GC, atomic absorption spectroscopy and titration. The exchange reaction between the ethoxy group of the support and the chloride group of TiCl4was found to depend profoundly on the halide compound and/or the internal donor used. The propene polymerizations were carried out using various Mg(OEt)2‐supported catalysts and triethylaluminium as cocatalyst with or without external donor (triethoxyphenylsilane). The catalyst activity and stereospecificity were exami

ISSN:0025-116X    

DOI:10.1002/macp.1990.021910702

出版商:Hüthig&Wepf Verlag    

年代:1990

数据来源: WILEY

摘要:

AbstractThe preparation of the three isomeric dimethyl derivatives4–6of 1H,8H‐pyrrolo[3,2‐g]indole (1), substituted at the nitrogen atoms or in the positions α and β to them, respectively, is described. These products were synthesized for investigating the regiochemistry of the electrochemical oxidative polymerization of the parent compound1. Anodic coupling in acetonitrile of the dimethyl derivatives4–6produces polymeric films which are reversibly oxidized with a charge exchange of 0,5 electrons per repeating unit. For5and6, coupling occurs in the free positions of the pyrrole rings, yielding a non‐conjugated and poorly conducting (5 · 10−6Ω−1· cm−1) polymer and a conjugated and conducting (1 Ω−1· cm−1) polymer, respectively. TheN‐substituted isomer4couples in the α‐positions and the resulting polymer shows a decrease in conductivity (10−2Ω−1· cm−1) relative to poly(1), analogous to that of poly(N‐methylpyrrole) relative to polypyrrole. Further comparisons of conductivity data and behaviour of the methyl substituted derivatives of1allow to conclude that the unsubstituted polymer coupl

ISSN:0025-116X    

DOI:10.1002/macp.1990.021910703

出版商:Hüthig&Wepf Verlag    

年代:1990

数据来源: WILEY

摘要:

AbstractThis work deals with the modification reaction of amylose with 1‐naphthylacetyl chloride using pyridine as catalyst and the DMF/LiCl system as solvent. The structure of the resulting polymers was determined by IR,1H and13C NMR spectroscopy. A linear dependence of the reaction rate on the concentration of polymer, 1‐naphthylacetyl chloride and pyridine was found. The activation energy was found to be 32,4 kJ/mol. The hydrolysis in the heterogeneous phase showed that the release of the active compound from tablets is dependent on the hydrophilic character of the modified amylose as well as on the pH value of the med

ISSN:0025-116X    

DOI:10.1002/macp.1990.021910704

出版商:Hüthig&Wepf Verlag    

年代:1990

数据来源: WILEY

摘要:

AbstractThis paper analyses in detail the dependence of the number of CS2tags in polypropene (PP) on the relative polymerization rate upon addition of CS2. It is shown that centers of higher activity are subjected to a faster deactivation and tagging by CS2. It was deduced that their higher reactivity with CS2is not likely to be connected with their stereospecificity. Irreversibility of the CS2‐insertion reaction was documented, at least under the conditions of our experimentation. A mechanism of action of CS2was outlined and adsorption coefficients were determined for the TiCl3/AlEt2Cl and TiCl3/AlEt3systems. A direct proof of insertion of CS2into the growing transition metal‐carbon bond could not be obtained. An indirect method (employing COS as a poison) allowed us to conclude that in case of CS2two atoms of sulfur are incorporated into the polymer per each deactivated center. On this basis, the number of centers was determined for both catalyst systems. A much higher propagation rate constant (kp) was found for the AlEt3‐cocatalyzed polymerization. It was concluded that the above method is applicable to the determination of active centers, but caution must be exerted in widening its application to other sy

ISSN:0025-116X    

DOI:10.1002/macp.1990.021910705

出版商:Hüthig&Wepf Verlag    

年代:1990

数据来源: WILEY

摘要:

AbstractThe reaction of dicarboxylic acid potassium salts with dibromo derivatives in 1‐methyl‐2‐pyrrolidone at moderate temperature was applied to the synthesis of high‐molecular‐weight co‐ and terpolyesters containing fumaric, maleic, phthalic and succinic ester residues and tetramethylene groups. Co‐ and terpolyesters with a random structure were obtained from the reaction of binary or ternary mixtures of salts with 1,4‐dibromobutane. While the composition in ester residues of the organic phase varies continuously during the first 6 h of the polycondensation reaction, that of the copolyesters obtained after 24 h is determined by the composition of the initial mixture of salts. The relative amounts of cyclicn‐mers produced in the course of the reaction and those of the different possible dimers were evaluated from GPC analyses of the reaction products. Multi‐block copolyesters were prepared either by the reaction of a potassium salt with a mixture of 1,4‐dibromobutane and a low‐molecular‐weight α‐ω‐dibromopolyester or by the coupling reaction of two low‐molecular‐weight α,ω‐dibromopolyesters with succinic acid potassium salt. The reaction of bis(4‐bromobutyl) phthalate and fumaric or maleic acid potassium salt produced the corresponding alternating copolyesters. Physico‐chemical and compositional data of the

ISSN:0025-116X    

DOI:10.1002/macp.1990.021910706

出版商:Hüthig&Wepf Verlag    

年代:1990

数据来源: WILEY

摘要:

AbstractThe vinyl ethers, α‐benzyloxyacrylonitrile (4), methyl α‐benzyloxyacrylate (5), and α‐benzyloxy‐acrylamide (6), act as sulfur‐free chain transfer agents in the polymerization of methyl methacrylate (chain transfer constantCx= 0,081–0.47), styrene (Cx= 0,036–0,14), methyl acrylate (Cx= 0,3–1,1), and vinyl acetate (Cx= 12–20) initiated by AIBN at 60°C. With methyl methacrylate and styrene, the conversions of the polymerizations are relatively unaffected by the vinyl ethers. With methyl acrylate and vinyl acetate, however, some retardation occurs. The activity of the compounds is compared with that of α‐benzyloxystyrene (1), which undergoes chain transfer by a novel free radical additi

ISSN:0025-116X    

DOI:10.1002/macp.1990.021910707

出版商:Hüthig&Wepf Verlag    

年代:1990

数据来源: WILEY

摘要:

AbstractThin films of organosilicon were prepared by glow discharge decomposition of phenylsilane in the presence of oxygen. As a result of spectral analyses and optical band gap measurements of the deposited films, the oxygen was found to be scarcely incorporated in the bulk of the films at least when the mole fraction of oxygen in phenylsilane was less than 0,5. The oxygen appeared to promote plasma polymerization of phenylsilane. The electric conductivity of the films prepared from mixed O2/C6H5SiH3was enhanced by iodine “doping” by four orders of magnit

ISSN:0025-116X    

DOI:10.1002/macp.1990.021910708

出版商:Hüthig&Wepf Verlag    

年代:1990

数据来源: WILEY

摘要:

AbstractA kinetic model of the homogeneous anionic polymerization of 1,4‐divinylbenzene (1,4‐DVB) in dilute solutions with instantaneous initiation and without cyclization and termination reactions is proposed. The monomer and pendant vinyl group conversions, degrees of polymerization of the primary chains and the crosslinking densities were predicted as a function of the reaction time as well as 1,4‐DVB and initiator (butyllithium) concentrations. The previous experimental data concerning the formation of the microgels can be explained using the kinetic mechanism of the polymerization reaction and neglecting cyclization. Calculations indicate that reactive 1,4‐DVB microgels can be synthesized in the whole concentration range of the in

ISSN:0025-116X    

DOI:10.1002/macp.1990.021910709

出版商:Hüthig&Wepf Verlag    

年代:1990

数据来源: WILEY

摘要:

AbstractThe dependence of propagation and termination rate coefficients on conversion in free‐radical polymerization is described by a purely kinetic model which considers contributions of segmental diffusion, translational diffusion, and reaction diffusion to termination and which also takes diffusion‐control of the propagation step into account. The kinetic scheme provides a satisfactory representation and interpretation of the termination rate coefficient measured in an extended range of conversion for ethylene, butyl acrylate, and methyl methacrylate polymerization. Reaction diffusion is of primary importance for termination at moderate and high conversion, which leads to fairly simple expressions for kinetic parameters even at conversions where the solution viscosity exceeds the pure monomer viscosity by several orders of magnit

ISSN:0025-116X    

DOI:10.1002/macp.1990.021910710

出版商:Hüthig&Wepf Verlag    

年代:1990

数据来源: WILEY