摘要:

Crystalline monomers of acrylamide (AAm) and methacrylamide (MAAm) could be polymerized in the presence of chlorine gas under ultraviolet (uv) irradiation, the shape of the solid crystals remaining unchanged during the polymerization. The yield of polymer increased with increasing amounts of chlorine. It was deduced that chlorine atoms formed by the decomposition of chlorine molecules on the monomer crystals with uv irradiation initiate the polymerization, which proceeds from the surface to the inner part of the crystals. One apparent characteristic of the catalytic solid-state polymerization is that the molecular weight of the polymer increases as polymerization temperature is raised.

ISSN:0022-233X    

DOI:10.1080/00222337008060962

出版商:Taylor & Francis Group    

年代:1970

数据来源: Taylor

摘要:

Flash pyrolysis of the copolymers acrylonitrile-methyl methacrylate and acrylonitrile-styrene has been carried out over the whole range of compositions, and yields of the monomers have been measured. In the first case, all of the methyl methacrylate is recovered as monomer except when a unit is isolated between two acrylonitrile segments. However, the yield in acrylonitrile monomer is lower; it corresponds to the units isolated between long sequences of methyl methacrylate plus the isolated acrylonitrile diads. The agreement between the calculated and experimental yields is excellent only if one takes into account the penultimate effects. In the second case, however, it is not possible to deduce a quantitative interpretation of the yields of either styrene or acrylonitrile monomers.

ISSN:0022-233X    

DOI:10.1080/00222337008060963

出版商:Taylor & Francis Group    

年代:1970

数据来源: Taylor

摘要:

In order to clarify the effects of the sulfur atom and the alkyl groups in alkyl vinyl sulfides (RVS) on their reactivities, the radical copolymerizations of eight RVS (M2) with styrene, methyl methacrylate, and acrylonitrile (Mi) were investigated at 60°C, and the copolymerization parameters were determined. It was found that the Q and e values for RVS were estimated as 0.3 ∼ 0.5 and -1.1 ∼ -1.7, respectively, from the copolymerizations with styrene, and these values were almost unchanged, regardless of the type of alkyl group in RVS. These results indicated that the electron-sharing, 3d orbital resonance between the growing radical derived from electron-donating RVS monomer and the adjacent sulfur atom was important in the transition state of copolymerizations.

ISSN:0022-233X    

DOI:10.1080/00222337008060964

出版商:Taylor & Francis Group    

年代:1970

数据来源: Taylor

摘要:

A previously unreported copolymer between furan and maleic anhydride was readily obtained by free radical initiation of benzene solutions of the comonomers. The product copolymers exhibit remarkably uniform composition regardless of monomer feed ratios. A donor-acceptor complex was suspected to account for the 1:1 alternating sequence of the monomers in the product. The complex was easily detected and partially characterized, although its exact role in the mechanism is uncertain.

ISSN:0022-233X    

DOI:10.1080/00222337008060965

出版商:Taylor & Francis Group    

年代:1970

数据来源: Taylor

摘要:

Styrene copolymerized with dimethyl itaconate and with methyl benzyl itaconate by use of a free radical initiator.

ISSN:0022-233X    

DOI:10.1080/00222337008060966

出版商:Taylor & Francis Group    

年代:1970

数据来源: Taylor

摘要:

Kinetic studies, using a gas chromatographic method, of the consumption of n-, sec-, and t-butyllithium during the polymerization of isoprene in cyclohexane show in the three cases a sigmoidal curve. When the concentration of polyisoprenyllithium increases, the initiation rate goes through a maximum with n-butyllithium but continuously increases in the two other cases. The three corresponding lithium-butoxides have a drastic effect on the initiation rate. Thus, the addition of n-butoxide strongly increases the initial rate, but the rate further decreases except in the case of sec-butyl-lithium. The behavior of the sec-butoxide is roughly the same, but more limited, while the t-butoxide causes a slight initial promotion in the case of n-BuLi and sec-BuLi but decreases the initiation rate in the case of t-BuLi. These results are discussed in terms of association of organolithium molecules and ion pairs reactivity.

ISSN:0022-233X    

DOI:10.1080/00222337008060967

出版商:Taylor & Francis Group    

年代:1970

数据来源: Taylor

摘要:

The kinetics of the propagation reaction in the polymerization of isoprene initiated by n-, sec-, or t-butyllithium, in the absence or in the presence of the three corresponding lithium butoxides, are studied in the two possible major cases. In the first case, the propagation takes place without simultaneous initiation; the reaction is then first-order versus the monomer concentration and one-sixth-order versus the polyisoprenyllithium concentration. The lithium butoxides decrease the propagation rate, but the effect is not very dependent on the nature of the butoxide. In the second case, the presence of the initiator decreases the propagation rate in a manner which depends on the concentrations of the reactants and on the nature of the initiator. The effect of the lithium butoxide is not simply additive. Depending on the relative concentrations, a synergistic effect may be observed. It is suggested that the active species are chiefly ion pairs of unassociated polyisoprenyllithium. Ion pairs from associated molecules may have limited activity.

ISSN:0022-233X    

DOI:10.1080/00222337008060968

出版商:Taylor & Francis Group    

年代:1970

数据来源: Taylor

摘要:

The copolymerization of isoprene or butadiene with acrylonitrile in the presence of zinc chloride or ethylaluminum sesquichloride, in the presence or absence of a free radical catalyst, at 30-70°C yields an equimolar, diene-acrylonitrile alternating copolymer containing more than 90% trans-1,4 unsaturation, irrespective of monomer charge. The copolymer results from the homopolymerization of a diene-acrylonitrile…metal halide transoid charge transfer complex. When ZnCl2is the electron-accepting metal halide and the polymerization is carried out at temperatures of 50°C and higher or to high conversions, the equimolar copolymer is accompanied by a high acrylonitrile polymer, and in the presence of a radical catalyst, by a normal radical copolymer. In the presence of the organoaluminum halide and in the absence of a radical catalyst, the alternating copolymer is the only product, irrespective of monomer charge. However, in the presence of a radical catalyst and at high acrylonitrile monomer charges, e.g., D/AN = 10/90, the alternating copolymer is accompanied by a normal radical copolymer. The formation of equimolar, alternating copolymer at all monomer ratios and in the absence or presence of a radical catalyst indicates that the (D-AN…MX) charge transfer complex readily undergoes homopolymerization and does not copolymerize with free diene or acrylonitrile or with the AN-AN…MX complex.

ISSN:0022-233X    

DOI:10.1080/00222337008060969

出版商:Taylor & Francis Group    

年代:1970

数据来源: Taylor

摘要:

An NMR investigation was carried out on variable composition, random and equimolar, alternating copolymers of acrylonitrile (A) with styrene (S), isoprene (I), and butadiene (B). The NMR spectra of the SA copolymers contained peaks at 3 τ (aromatic ring protons), 7.2-7.5 τ (CH protons of A), and 8.1 -8.5 τ (CH and CH2protons of S and CH2protons of A). All NM R peaks of the alternating SA copolymer were shifted to the higher field due to the shielding effect of S. The NMR spectra of the IA copolymers contained peaks at 4.72-4.91 τ (˭CH protons of I), 7.27-7.4 τ (CH protons of A), 7.71-7.93 τ (CH2protons of I), and 8.35 τ (CH3protons of I and CH2protons of A). The peaks at 4.72 τ (˭CH) and 7.72 τ (CH2) were assigned to I in the I-A diad and the peaks at 4.91 τ (˭CH) and 7.93 τ (CH2) were assigned to I in the I-I diad. The NMR spectra of the BA copolymers contained peaks at 4.4-4.6 τ (˭CH protons of B), 7.2-7.5 τ (CH protons of A), 7.71-7.97 T (CH2protons of B), and 8.0-8.4 τ (CH2protons of A). The peaks at 4.42 τ (˭CH) and 7.71 τ (CH2) were assigned to B in the B-A diad and the peaks at 4.6 τ (˭CH) and 7.9 τ(CH2) were assigned to B in the B-B diad. The alternating structure of the copolymers prepared through metal halide-activated complexes was confirmed by NMR analysis. The random copolymers prepared by free radical initiation contain a high concentration of alternating sequences, as anticipated from the values of r1and r2where r1(S, I, and B) is 6-10 times higher than r2(A).

ISSN:0022-233X    

DOI:10.1080/00222337008060970

出版商:Taylor & Francis Group    

年代:1970

数据来源: Taylor

摘要:

Transamidation reactions of nonpolymerizing systems involving benzamides, phthalimides, arylsulfonamides, benzenedisulfonamides and -disulfonim-ides, and saccharins are described. The study includes reactions of both N-substituted and unsubstituted amides and imides with anilines and aniline hydrochlorides. An evaluation of the results of these reactions, aimed at establishing the optimum conditions for transamidations in polymerizing systems, is also presented.

ISSN:0022-233X    

DOI:10.1080/00222337008060971

出版商:Taylor & Francis Group    

年代:1970

数据来源: Taylor