摘要:

The known reaction of condensation of a strong amine with phloroglucine under quite mild conditions was the starting point for synthesis of a new series of macromolecular resins not previously dèscribed. Phloroglucine has been condensed with a series of nine aliphatic diamines in aqueous solution under atmospheric pressure. The resins obtained are dark powders, which can be molded under increased pressure in the temperature range of 175–310°C. The thermal, mechanical, chemical, and electrical properties of the new resins have been examined and their structure confirmed. Some properties of resins can be calculated by means of approximate mathematical formulas.

ISSN:0022-233X    

DOI:10.1080/00222337808063188

出版商:Taylor & Francis Group    

年代:1978

数据来源: Taylor

摘要:

Polymerization of acrolein(AL) in the presence of imidazole(Im) has been investigated in tetrahydrofuran or methanol below room temperature. The polymers obtained, white or pale yellow powders, were found to be composed of vinyl polymer with one Im group attached and having an aldehyde side chain, of which 70–80 mole % of the aldehyde revealed bridge structure. The number-average molecular weight (Mn) of these polymers was determined to be in the range of 317 to 691. The rate of polmerization Rpwas expressed by the equation, R + k[Im] [AL]2.

ISSN:0022-233X    

DOI:10.1080/00222337808063189

出版商:Taylor & Francis Group    

年代:1978

数据来源: Taylor

摘要:

The aqueous polymerization of methacrylamide initiated by the ammonium persulfate/thiolactic acid redox system has been studied at 35 ± 0.2°C. The rate of polymerization is governed by the expression, Rp+ Kp[MAA]1.33[TLA]0.22[ammonium persulfate]0.6. The deviations from normal kinetics are discussed. A tentative mechanism of initiation is given. The temperature dependence of the rate of polymerization has been studied over the range 30–55°C. The overall activation energy of polymerization is 10.4 kcal/mole.

ISSN:0022-233X    

DOI:10.1080/00222337808063190

出版商:Taylor & Francis Group    

年代:1978

数据来源: Taylor

摘要:

1-Isopropenylnaphthalene has been dimerized by cationic initiation. The structure of the dimer does not depend on the initiator. The cyclization of the dimeric ion takes place on carbon 8 (peri). The structure has been established both by x-ray diffractometry and by NMR. The complete crystallographic structure has been determined. The dimers of various substituted isopropenylnaphthalenes have been obtained in the same way and have the same structure.

ISSN:0022-233X    

DOI:10.1080/00222337808063191

出版商:Taylor & Francis Group    

年代:1978

数据来源: Taylor

摘要:

When every valency in n monomer units is assigned an individual index number, a unique formula can be written for each non-cyclic n-mer by systematically listing the pairs of valencies forming the (n - 1) bonds. The chosen system allows the formulae to be partitioned into families and subfamilies and the number of ways of pairing the valencies in any set to be deduced. This leads to a new method of calculating the number of ways of forming noncyclic n-mers.

ISSN:0022-233X    

DOI:10.1080/00222337808063192

出版商:Taylor & Francis Group    

年代:1978

数据来源: Taylor

摘要:

The radiation-induced polymerization of ethyl vinyl ether was studied in n-pentane and neopentane solutions under super-dry conditions. The free ion yields of these solvents are reported to be 0.16 and 1.0, respectively. The rate of polymerization in neopentane was about twice as fast as in n-pentane. The dose-rate dependence of the rate of polymerization was found to be nearly 0.50 in both solutions. It seems clear that the free solvent ions do, indeed contribute to the initiation. Regenerative chain transfer to monomer played a more important role in n-pentane than in neopentane as revealed by the molecular weight of the polymers.

ISSN:0022-233X    

DOI:10.1080/00222337808063193

出版商:Taylor & Francis Group    

年代:1978

数据来源: Taylor

摘要:

Radiation-induced polymerization of methyl methacrylate (MMA) was studied up to 7500 kg/cm2at 20°C. The rate of polymerization increased to 3000 kg/cm2with overall activation volume ΔVpol‡ of -23.6 cm3/mole, and then the pressure dependence of the rate was very small in the pressure range between 3000 and 3700 kg/cm2. The rate of polymerization increased again above 3700 kg/cm2up to the crystallization pressure of MMA (5500 kg/cm2) with ΔVpol‡ of -13.7 cm3/ mole with increasing pressure. The volume contraction by polymerization decreased with increasing pressure up to 3000 kg/cm2but hardly decreased with increasing pressure above 3000 kg/cm2. The stereoregulzarity (triad probability) of PMMA changed slightly at 3000 kg/cm; above 3000 kg/cm2, syndiotactic addition decreased and heterotactic addition increased. Marked change in P-V isotherms of MMA, however, was not observed about 3000 kg/cm2. We concluded from these facts that an alignment of monomer molecules, which does not cause large volume change, was realized about 3000 kg/cm2. Polymerization proceeded above the crystallization pressure by long time irradiation, and isotactic addition increased clearly in the solid-state polymerization.

ISSN:0022-233X    

DOI:10.1080/00222337808063194

出版商:Taylor & Francis Group    

年代:1978

数据来源: Taylor

摘要:

The pressure-volume (P-V) isotherms were measured for the poly(methy1 methacrylate) (PMMA)-methyl methacrylate (MMA) coexistence system polymerized by γ-ray irradiation at various pressures. The P-V isotherm of the coexistence system polymerized below 3000 kg/cm2was similar to that of the monomer. The specific volume of the coexistence system polymerized above 3000 kg/cm2hardly changes in the pressure range between 3000 kg/cm2and the polymerization pressure when measurements are made with successively decreasing or successively increasing pressures. The compressibility was of the order of 10−6(kg/cm2)−1in this pressure range. This indicated that the coexistence system polymerized above 3000 kg/cm2behaves like a solid in this pressure range. Above the polymerization pressure, the compressibility was of the order of 10−5(kg/cm2)−1, indicating that the coexistence system behaves as liquid. We concluded that the solid-like behavior of the coexistence system polymerized above 3000 kg/cm2is caused by a strong interaction between as-polymerized polymer chains and monomer molecules due to propagation through monomer clusters having short-range order. The present results support that MMA is aligned in short-range order at suitable pressure and temperature as reported in the preceding paper.

ISSN:0022-233X    

DOI:10.1080/00222337808063195

出版商:Taylor & Francis Group    

年代:1978

数据来源: Taylor

摘要:

Radiation-induced polymerization of n-butyl and n-hexyl methacrylates (BMA, HMA) at high pressure (up to 8000 kg/cm2) and pressure-volume (P-V) behavior of the polymer-monomer coexistence systems at various pressures were studied by dilatometric method. The Van't Hoff plot of the rate of polymerizations broke at 3500 and 4500 kg/cm2for BMA and HMA, respectively. (first breaks). The activation volumes were about -24 cm3/mole for both monomers below the pressure giving the first breaks. The pressure dependences on the rate of polymerizations were small in the pressure ranges of the first break pressures to 4500 kg/cm2for BMA and 5500 kg/cm2for HMA (second breaks), and above the second break pressures the rate of polymerizations increased with constant activation volumes with increasing pressure. The P-V isotherms of the coexistence systems polymerized below 3000 kg/cm2were the same as those of the monomers, and the coexistence systems polymerized at 3800 (BMA) and 4200 kg/cm2(HMA) showed solidlike features in the pressure range of 3000 kg/cm2to the polymerization pressures. The coexistence systems polymerized at 5500 (BMA) and 6500 kg/cm2(HMA) showed solidlike features in the range of 4500 kg/cm2to the polymerization pressure and 5500 kg/cm2to the polymerifation pressure, respectively. The pressure of 4500 kg/cm2for BMA and 5500 kg/cm for HMA corresponded to the pressure giving the second break in the Van't Hoff plot. We concluded from these results that the solidlike features were due to a strong interaction between as-polymerized polymer chains and monomer molecules similarly to the case of the PMMA-MMA coexistence system, and that the ester chains of BMA and HMA play an important role in alignment of monomer molecules above 4500 (BMA) and 5500 kg/cm2(HMA).

ISSN:0022-233X    

DOI:10.1080/00222337808063196

出版商:Taylor & Francis Group    

年代:1978

数据来源: Taylor

摘要:

Radiation-induced polymerization and pressure-volume (P-V) measurements of acrylonitrile (AN) were studied up to 8000 kg/cm2in the temperature range of 6–72°C. P-V isotherms of AN have several small breaks, A phase diagram of AN was obtained from the breaking pressures and temperatures. Liquid phases were named LI, LII, and LIII, from low to high pressure. The polymerization behavior and volume contraction on polymerization changed in LI, LII, and LIII. The difference in entropy between original and activated states decreased with increasing pressure at the same phase, but increased with phase change in LIto LIIand LIIto LIII. It was concluded from these results and from IR data on PAN that molecular packing of AN in liquid changed in LI, LII, and LIII. In LIIand LIII, AN molecules aligned in a less suitable geometry for polymerization than in LI.

ISSN:0022-233X    

DOI:10.1080/00222337808063197

出版商:Taylor & Francis Group    

年代:1978

数据来源: Taylor