摘要:

Two esters ofL-lysine andL-glutamic acid containing long alkyl groups were synthesized and their polycondensation in monolayers and multilayers was investigated. The pressure-area isotherms of the ester ofL-lysine depend markedly on the time of residence at the air-water interface. The change of FT-IR spectra of the deposited film, which can be lifted as a Z-type film, indicates that polycondensation can occur in the monolayer at 10°C without any treatment. The spectrum of the film cast from chloroform hardly changed with time. These results lead to the conclusion that a regular arrangement of monomer molecules in the monolayer, where the amino and ester carbonyl groups are concentrated, is more suitable for the polycondensation. The ester ofL-glutamic acid can also form stable monolayers which can be easily deposited on a hydrophobic plate as a Y-type film by the Blodgett technique. The polycondensation of multilayers under an atmosphere of triethylamine was investigated by IR spectroscopy. It indicates that the condensation in multilayers proceeds via intermolecular and intramolecular reactions, by which poly(L-glutamate) derivatives and 2-pyrrolidone derivatives are formed, respectively. The condensation in the bulk crystalline powder gives exclusively the 2-pyrrolidone derivative by intramolecular reaction. These results suggest that the monomer molecules in the multilayers are favorably aligned for the intermolecular reaction, in contrast to the situation in the bulk crystalline powder.

ISSN:0022-233X    

DOI:10.1080/00222338908052074

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor

摘要:

New polymaleamides were synthesized by ring-opening polyaddition ofN,N'-biphenylbismaleimide (BPBMI) to the aliphatic diamines 1,4-diaminobutane, 1,6-diaminohexane, 1,8-diaminooctane, piperazine, and 2,5-dimethylpiperazine inm-cresol. The appropriate model compound was also prepared. These polymers are completely soluble in concentrated sulfuric acid as well as inm-cresol and are found to be insoluble in common organic solvents. The identities of BPBMI, the model compound, and the polymaleamides were confirmed by elemental analysis and IR spectroscopy. These polymaleamides were found to have inherent viscosities in the range 0.10–0.14 dL/g. Their IR spectra reveal the retention ofcis-geometry about the C=C bonds in BPBMI and in the polymaleamides. The thermal degradation behavior of the polymaleamides was studied by thermogravimetric analysis, differential scanning calorimetry, and mass spectrometry. Fragmentation schemes for the polymaleamides are proposed.

ISSN:0022-233X    

DOI:10.1080/00222338908052075

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor

摘要:

Optically active di-L-menthyl itaconate (DMI) was prepared from itaconic acid andL-menthol. DMI was polymerized in bulk at 80°C to give a chiral homopolymer having a specific rotation of -76.9°. DMI (M1) was copolymerized with styrene (ST,M2),N-cyclohexylmaleimide (CHMI,M2), vinyl acetate (VAc,M2) and methyl methacrylate (MMA,M2) with azobisisobutyronitrile in benzene at 50°C. The monomer reactivity ratios (r1,r2) and Alfrey-PriceQ, evalues were determined asr1= 0.56,r2= 0.55,Q1= 0.76,e1= 0.29 for DMI-ST;r1= 0.0,r2= 5.6 for DMI-MMA;r1= 0.0,r2= 0.25 for DMI-VAc; andr1= 0.31,r2= 0.56 for DMI-CHMI. The chiroptical properties of the polymers were investigated.

ISSN:0022-233X    

DOI:10.1080/00222338908052076

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor

摘要:

Electroinitiated polymerization of the bis(2,6-dibromo-4-chlorophenoxo)-N,N,N',N'-tetramethylethylenediamine copper(II) complex was accomplished upon anodic oxidation in acetonitrile. Anodic and cathodic peak potentials of the complex were measured by cyclic voltammetry (CV) in advance. Constant potential electrolyses carried out at peak potentials yielded polymers only in the anolyte. The presence of polymers in the anode compartment and the effect of radical inhibitor indicated a free-radical mechanism. In the absence of current, the complex in acetonitrile did not yield any trace of polymer for 10 days. The electrochemically produced radicals were very stable. When the polymerization was started by electroinitiation, it continued after discontinuance of the current. In order to follow the rate of monomer consumption, CV was employed. Use of six electrodes, in the specially designed H-type cell, allowedin situ, simultaneous monitoring of the monomer concentration. The structure of the polymer was studied by1H-NMR,13C-NMR, and FTIR spectral analyses. Molecular weight measurements were carried out by the isopiestic method.

ISSN:0022-233X    

DOI:10.1080/00222338908052077

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor

摘要:

N-(Butyl-3-one)imidazole acts as an initiating adduct which is formed in the anionic polymerization of methyl vinyl ketone (MVK) induced by imidazole (Im) and is directly formed from Im and the MVK monomer. The kinetics of the anionic homopolymerization of MVK and acrylamide (AAm) under argon in the presence of the adduct were investigated in tetrahydrofuran (THF). The rate of polymerization for the MVK system is expressed asRp=k[Adduct] [MVK], wherek= 3.1 × 10−6L/(mol·s)in THF at 30°C. The overall activation energy,Ea, was found to be 5.34 kcal/mol. TheRpfor the AAm system is expressed asRp=k[Adduct] [AAm], wherek= 6.8 × 10−6L/(mol·s) in THF at 30°C, withEa7.78 kcal/mol. The mechanism of the polymerization induced by the initiator adduct is discussed on the basis of these results.

ISSN:0022-233X    

DOI:10.1080/00222338908052078

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor

摘要:

In the preceding papers of this series, we reported the synthesis of liquid-crystalline polyurethanes containing mesomorphic moieties in the main chain and in side chains [1–4]. Liquid crystalline polymers with side groups containing the cholesterol moiety have also been studied [5, 6]. The main focus of attention has centered around the study of phase transitions of acrylic and methacrylic derivatives of cholesterol. This paper describes the synthesis of a new type of liquid-crystalline polyurethane containing the cholesterol moiety in side chains.

ISSN:0022-233X    

DOI:10.1080/00222338908052079

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor

摘要:

Polymerization of vinyl acetate continues to interest workers in the field as evidenced by recent publications [1–3]. However, little information is available concerning the synthesis of low molecular weight poly(vinyl acetate) (PVAc) despite its industrial importance.

ISSN:0022-233X    

DOI:10.1080/00222338908052080

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor

ISSN:0022-233X    

DOI:10.1080/00222338908052073

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor