摘要:

In an effort to determine the feasibility of formation of larger rings from dialkenyl silanes by the cyclopolymerization mechanism through use of Ziegler-type initiators, four new silane monomers were synthesized and their polymerization studied. Allyldimethyl-(3-butene-1)-silane(I)and allyldiphenyl-(3-butene-1)-silane(III)are functionally capable of producing polymers containing a seven-membered ring. Dimethyl-bis-(3-butene-1)-silane(II)and diphenyl-bis-(3-butene-1)-silane(IV)are functionally capable of producing polymers containing an eight-membered ring. The diphenyl monomers gave benzene-soluble, solid polymers containing a low degree of residual unsaturation, interpreted as evidence that the predicted cyclization had occurred. The dimethyl derivatives, on the contrary, gave only viscous oils or semisolid products which could not be well characterized.

ISSN:0022-233X    

DOI:10.1080/10601326908051947

出版商:Taylor & Francis Group    

年代:1969

数据来源: Taylor

摘要:

A number of 4-substituted 1,6-heptadienes have been prepared and their infrared absorption characteristics compared with their polymerizability. This group of compounds included several N,N-diallylamides, diallylcyanamide, diallyl-(tricyanovinyl)-amine, diallylammonium bromide, diallylmethylphosphine oxide, diallylphenylphosphine oxide, diallylmethylphenylphosphonium bromide, and dimethyl-4-penteneamine. The frequencies of the in-plane-deformation vibration of the terminal methylene groups varied from 1411 to 1437 cm−1. The higher frequencies were attributed to the electron withdrawal effect of the substituent in the 4 position. Those compounds having higher absorption frequencies also undergo polymerization more readily than those in the lower-frequency range. These correlations are presented as substantiating evidence for an intramolecular interaction in the monomers which can in part explain the facile but highly improbable cyclopolymerization mechanism.

ISSN:0022-233X    

DOI:10.1080/10601326908051948

出版商:Taylor & Francis Group    

年代:1969

数据来源: Taylor

摘要:

In order to obtain fundamental information for polymerization of some acrylic monomers in the glassy state, glass formation and the characteristics of multicomponent systems containing acrylic monomers were investigated. Glassy states were obtained by selecting the proper balance of three conditions: supercooling tendency of the mixtures, second-order transition temperatures, and cooling rate. Systems that form glasses at -78°C were classified into Type I (monomer as part of glass-forming matrix) and Type II (monomers dissolved in glass-forming matrix). All multicomponent systems containing acrylamide or acrylic acids form a glassy state at liquid nitrogen temperature. The phase diagrams of glassy systems of Type I show the formation of a molecular complex in the range of the glass-forming composition. Second-order transition temperatures were determined dilatometrically. Finally, the formation and structures of the supercooled state were identified by studying their infrared spectra.

ISSN:0022-233X    

DOI:10.1080/10601326908051949

出版商:Taylor & Francis Group    

年代:1969

数据来源: Taylor

摘要:

The radiation-induced polymerization of glass-forming systems containing vinyl monomers was investigated. Irradiation below the secondorder transition temperature (Tg) of the systems causes no in-source polymerization but does cause a very rapid postpolymerization in the course of heating above Tg. Differential thermal analysis was carried out to estimate Tgand to follow the postpolymerization.

ISSN:0022-233X    

DOI:10.1080/10601326908051950

出版商:Taylor & Francis Group    

年代:1969

数据来源: Taylor

摘要:

A comparison of the dilatometrically determined rates of polymerization of pure meta-and pure para-divinylbenzenes confirms the previous observation that the meta isomer polymerizes more rapidly than the para isomer. This difference shows up also in the initiator square root rate dependencies, the gel times, and the conversions at gel point. The effect of added regulator (carbon tetrabromide) on the polymerization of the meta isomer is to decrease the gel time and conversion at gel time.

ISSN:0022-233X    

DOI:10.1080/10601326908051951

出版商:Taylor & Francis Group    

年代:1969

数据来源: Taylor

摘要:

In order to clarify the effect of the substituents ina-substituted acrylonitriles and acrylic esters on their relative reactivities toward a polystyryl radical, the radical copolymerizations of diethyl methylenemalonate, ethyla-chloroacrylate, ethyla-bromoacrylate,a-chloroacrylonitrile, methyla-methoxyacrylate, anda-methoxyacrylonitrile with styrene (M2) were investigated at 60°C. From the copolymerization parameters obtained in this study and those reported in the literature, it was confirmed that theasubstituents additively contributed to the values of log Q and e of the monomers. Hence, the reactivities ofa-substituted acrylonitriles and acrylic esters relative to unsubstituted acrylonitrile and methyl acrylate toward polystyryl radical, respectively, were expressed by the following equation: log (rel. react.) = δlog QX+ 0.83 σp where δ log Qxand σp are the resonance and polar substituent constants of α substituents, respectively. The values of δ log Qxwere determined for CH30, CH3, C6H5, Cl, Br, OCOCH3, COOCH3, and CN substituents, and these values were closely related to the other resonance substituent constants such as ER and R of corresponding substituents, except for OCH3substituent. This relationship could also be applied to monosubstituted ethylenic monomers by using the same parameters. However, the reactivities of a-substituted styrenes deviated from this relationship because of the low ceiling temperatures of these monomers.

ISSN:0022-233X    

DOI:10.1080/10601326908051952

出版商:Taylor & Francis Group    

年代:1969

数据来源: Taylor

摘要:

Oligomerization of butadiene with the catalyst system of nickel(II)chloride, electron donor, and lithium aluminum hydride or sodium borohydride has been studied. Most oligomers obtained with this catalyst were linear, and dihydrogenated dimers, trimers, and tetramers. They were n-octa-1,6-diene, n-octa-1,7-diene, n-dodeca-1,6,10-triene, and n-hexadeca-1,6,10,14-tetraene, which were identified by means of infrared, nuclear magnetic resonance, and mass spectrometry. Yields of each oligomer were strongly affected by the nature of the electron donors used. The hydrogen required for the formation of the hydrooligomers was assumed to originate from the lithium aluminum hydride or sodium borohydride used as a reducing agent. A proposed mechanism for the hydrooligomerization is that butadiene is oligomerized on the nickel atom, and the produced oligoolefins, bonded to the nickel by two terminal π-allylic bonds, are dihydrogenated to linear hydrooligomers.

ISSN:0022-233X    

DOI:10.1080/10601326908051953

出版商:Taylor & Francis Group    

年代:1969

数据来源: Taylor

摘要:

The distribution of the alkoxide groups obtained in the metallation of starch in dimethyl sulfoxide solution by alkali metal naphthalenes was studied. The starch alkoxide was reacted with methyl iodide, and the methylated starch was hydrolyzed and analyzed for glucose and O-methyl glucose derivatives. The metallation reaction was found to be random, as seen from the fact that at low alkoxide concentration (D.S = 0.6), 2,3,6-tri-O-methyl glucose was formed, while at relatively high alkoxide concentration (D.S. = 1.5) unreacted glucose was still present. At low alkoxide concentration (D.S. ⋍ 0.6) there was, to a certain extent, preferential metallation at the C2hydroxyl groups, and to a lesser extent at the C6hydroxyl groups, as seen from the relative molar ratios of about 10:4:1 of the 2-, 6-, and 3-O-methyl glucose derivatives obtained, respectively. An increase in the metallation at the C3hydroxyl occurred with increasing alkoxide concentration. The distribution of the methoxyl groups with the three alkali metals potassium, sodium, and lithium was similar; there were differences only in the ease of metallation of the starch by the various alkali metal naphthalenes and in the efficiency of the coupling reaction with methyl iodide.

ISSN:0022-233X    

DOI:10.1080/10601326908051954

出版商:Taylor & Francis Group    

年代:1969

数据来源: Taylor

摘要:

A kinetic model is derived for the acid-catalyzed decomposition of Delrin, an acetal-formaldehyde resin. The kinetic model proposed assumes the hydrolysis of Delrin to form polyformaldehyde and the subsequent decomposition of polyformaldehyde to formaldehyde.

ISSN:0022-233X    

DOI:10.1080/10601326908051955

出版商:Taylor & Francis Group    

年代:1969

数据来源: Taylor

摘要:

In an effort to lend some insight into the probabilistic nature of step-growth kinetic processes, the differential rate expression for anionic polymerization with one rate constant is derived from stochastic theory.

ISSN:0022-233X    

DOI:10.1080/10601326908051956

出版商:Taylor & Francis Group    

年代:1969

数据来源: Taylor