摘要:

AbstractThe main kinetic behavior of the slurry polymerization of propene with a MgCl2‐supported TiCl4/C6H5COOC2H5catalyst, activated by Al(C2H5)3, was studied, Examination of the dependence of the polymerization rate on temperature and concentrations of Al(C2H5)3and of propene resulted in a Langmuir‐Hinshelwood rate law with the number of polymerization centers dependent on time. The Polymerization rate as function of the polymerization temperature shows a maximum, which is compatible with the rate law. The analysis of the phenomenon of an optimum temperature gave 15 KJ. mol−1and 36 KJ. Mol−1for the activation energy of the rate determining step and the adsorption energy of Al(C2H5)3, respectively. Examination of the rapid decay of the polymerization rate showed that the main part of the decay is represented by a second order decay independent of the amount of polymer produced, which can be understood by a second order decay of surface sites by Al(C2H5)3. The number of active centers of the catalyst in gas phase polymerization was estimated applying the inhibition method with carbon monoxide. The results show a constant value for the propagation rate constant,Kp, during the second order rate decay. The observed polymerization kinetics strongly suggest the existence of two kinds of polymerization centers (isotactic and a

ISSN:0025-116X    

DOI:10.1002/macp.1982.021831001

出版商:Hüthig&Wepf Verlag    

年代:1982

数据来源: WILEY

摘要:

AbstractThe protamine salmine was immobilized on CNBr‐Sepharose 4B without involving the arginine side‐groups. The optimum conditions for the immobilization on a preparative scale were investigated in a series of analytical experiments. A Maximum yield (206 mg salmine/g dry salmine‐sepharose) was achieved at a pH‐value of 8, a gel concentration of 10 mg/ml suspension volume and a salmine sulfate concentration of 5 mg/ml reaction solution. An equation was developed to calculate the maximum immobilization of peptides on CNBr‐Sepharose 4B assuming known molecular weights of t

ISSN:0025-116X    

DOI:10.1002/macp.1982.021831002

出版商:Hüthig&Wepf Verlag    

年代:1982

数据来源: WILEY

摘要:

AbstractThe synthesis and phase behaviour of a series of polymers having liquid crystalline sidechains and a poly(acrylic acid) backbone are described. These polymers show a dependence of the phase transition temperatures on molecular weight. In copolymers of two liquid crystalline acrylic esters, induced smectic phases occur. A comparison of the phase transitions of the different polyacrylates, with those of liquid crystalline polymethacrylates and polysiloxanes, published elsewhere, establishes that the spacer group achieves partial “decoupling” of liquid crystalline and polymer propert

ISSN:0025-116X    

DOI:10.1002/macp.1982.021831003

出版商:Hüthig&Wepf Verlag    

年代:1982

数据来源: WILEY

摘要:

AbstractThe heterogeneous hydrolysis of poly(2‐pyrrolidone) with 1,1 M and 0,5 M KOH and HCI solutions in the temperature range 30–60°C was investigated. The course of the reaction was characterized by the decrease of weight of insoluble polymer and by the number of split bonds in the chain. The reaction proceeds in two stages different in rate; the possible reasons of the initial higher reaction rate are discu

ISSN:0025-116X    

DOI:10.1002/macp.1982.021831004

出版商:Hüthig&Wepf Verlag    

年代:1982

数据来源: WILEY

摘要:

AbstractSeveral telomers were prepared by redox catalysis from 2‐hydroxyethyl acrylate (1) and telogens such as carbon tetrachloride, methyl trichloroacetate, 1, 1, 1‐trichlorotrifluoroethane, and 2,4,4,4‐tetrachloro‐2‐methylbutyric acid (2d), as well as block‐cotelomers from1and a telomer4prepared from chlorotrifluoroethylene and carbon tetrachloride. Polyols (3a–dand5) with two to twenty primary hydroxyl groups were obtained. They were esterified with acrylic acid, to obtain new photosensitive composi

ISSN:0025-116X    

DOI:10.1002/macp.1982.021831005

出版商:Hüthig&Wepf Verlag    

年代:1982

数据来源: WILEY

摘要:

AbstractRedox of radical telomerizations of methyl 10‐undecenoate(1)with different telogens such as CCl4, CCl3Br, CCl3CF3, HPO (OEt)P2or different adducts of CCI4, on vinylidene chloride and chlorotrifluoroethylene, were studied. Chemical transformation of the end of the chains led to the corresponding difunctional compounds. Starting with these last compounds, polycondensation reactions were carried ou

ISSN:0025-116X    

DOI:10.1002/macp.1982.021831006

出版商:Hüthig&Wepf Verlag    

年代:1982

数据来源: WILEY

摘要:

AbstractSeveral telomers of methyl 10‐undecenoate were prepared with different telogens and identified by IR and NMR spectroscopy or by GPC. Chemical transformations of these telomers led to new polyhalogenated acids of alcohols having high molecular weight

ISSN:0025-116X    

DOI:10.1002/macp.1982.021831007

出版商:Hüthig&Wepf Verlag    

年代:1982

数据来源: WILEY

摘要:

AbstractDithioester groups were introduced into linear or crosslinked polystyrenes by Friedel‐Crafts reaction with ClCH2Si(CH3)3/CS2or with ethyl chlorodithioformate, as well as thioamide groups by reaction with ethoxycarbonyl isothiocyanate. Treatment of several copolymers of acrylonitrile with ethanethiol and hydrogen chloride and subsequently with H2S led to copolymers with dithioester and thioamide groups in the side chains without cyclization. Most of these reactions occur without crosslinkin

ISSN:0025-116X    

DOI:10.1002/macp.1982.021831008

出版商:Hüthig&Wepf Verlag    

年代:1982

数据来源: WILEY

摘要:

AbstractDithiocarboxylic groups as side groups on linear or crosslinked polymers were transformed quantitatively into the corresponding thioamides by ammonia and primary or secondary amines, whereas reaction with 1,2‐diaminoethane led to poly(Δ2‐imidazoline)s. Due to the high reactivity of carboxymethyl diethioesters [(2‐thioacylthio)acetic acid] the fixation of amino acids, dipeptides, and amino dyes on macromolecular chains was realized with high

ISSN:0025-116X    

DOI:10.1002/macp.1982.021831009

出版商:Hüthig&Wepf Verlag    

年代:1982

数据来源: WILEY

摘要:

AbstractA spectroscopic and conductimetric study of the cationic polymerization of 2‐vinylfuran(1)and 2‐methyl‐5‐venylfuran(2)showed the existence of an important side reaction originating from a hydride‐ion shift from an unsaturated polymer molecule to an active species. The resulting allylic carbocation, in equilibrium with a doubly unsaturated polymer molecule, can react further and the repetition of the mechanism on progressively more conjugated species leads to the formation of a series of highly charge‐delocalized carbenium ions absorbing throughout the visible region of the spectrum (and giving high electrical conductivity) and of neutral polyconjugated polymer molecules. Since the hydride‐ion abstraction occurs from the tertiary carbon atom of the vinylic chain, vinylidene polymers of monomers such as 2‐isopropenylfuran(3)and 2‐isopropenyl‐5‐methylfuran(4)are not susceptible to it. Indeed, their cationic polymerization proceeds without colour formation and

ISSN:0025-116X    

DOI:10.1002/macp.1982.021831010

出版商:Hüthig&Wepf Verlag    

年代:1982

数据来源: WILEY