摘要:

The polymerization of allene induced by organoaluminum-vanadium oxytrichloride catalysts has been investigated in aliphatic hydrocarbons and at normal pressure. For the catalysts investigated, the polymerization activity decreases at decreasing order of alkylation of the aluminum alkyl: AIR3> AIR2X > AIRX2(R is Et or i-Bu; X is halogen). Compared with other aluminum trialkyls, trimethylaluminum shows a low activity. For the Al-i-Bu3-VOCl3system, the effects of catalyst ratio, reaction time, and temperature have been studied.

ISSN:0022-233X    

DOI:10.1080/00222336808053343

出版商:Taylor & Francis Group    

年代:1968

数据来源: Taylor

摘要:

Polyallenes prepared with the aid of organoaluminum-VOCl3catalysts appear to exist in three distinct phases: two crystalline phases (I and II) and an amorphous phase. Phase I shows two strong X-ray diffraction peaks at d = 5.62 Å and d = 4.04 Å; phase II has three strong peaks at d = 6.28 Å, d = 5.03 Å, and d = 4.21 Å. The band of the amorphous phase has its maximum at about d = 5.6 Å.

ISSN:0022-233X    

DOI:10.1080/00222336808053344

出版商:Taylor & Francis Group    

年代:1968

数据来源: Taylor

摘要:

The polymerization activity of several allenes under the influence of Al-i-Bu3-VOCl3, and structure and properties of the solid polymers obtained, have been studied. Allene; butadiene-1, 2; hexadiene-1, 2; 3-methylbutadiene-1, 2; 3-methylpentadiene-1, 2; and pentadiene 2, 3 could be converted into soluble, solid polymers. 2-Methylpentadiene-2, 3; tetramethylallene; and tetraphenylallene did not react under the polymerization conditions applied. The following order of polymerization activity seems to be valid: CH2˭C˭CH2> R1CH˭C˭CH2> R1R2C˭C˭CH2≥ R1CH˭C˭CHR2, > R1R2C˭C˭CHR3≥ R1R2C˭C-CR3R4. The polymers of the homologues of allene were obtained as amorphous solids with the exception of poly(3-methyl-butadiene-1, 2), which was fairly crystalline.

ISSN:0022-233X    

DOI:10.1080/00222336808053345

出版商:Taylor & Francis Group    

年代:1968

数据来源: Taylor

摘要:

A crystal of N-vinylcarbazole was polymerized by redox catalyst (ammonium persulfite/sodium bisulfate) in a suspended state in water and poly (vinyl carbazole) was obtained. The polymerization proceeded rapidly above 40°C without an induction period in the solid state. The molecular weight of the polymer increased with decreasing catalyst concentration and raising temperature. ηsp/cof polymer was in the range 0.04–0.07 and it was lower than that obtained in radiation-induced solid-state polymerization. Observation of the partially polymerized crystal through a polarizing microscope showed that the polymerization proceeded from the surface of the monomer crystal and that birefringence was observed in the polymer layer. In X-ray diffraction studies it was found that the polymer was crystalline.

ISSN:0022-233X    

DOI:10.1080/00222336808053346

出版商:Taylor & Francis Group    

年代:1968

数据来源: Taylor

ISSN:0022-233X    

DOI:10.1080/00222336808053347

出版商:Taylor & Francis Group    

年代:1968

数据来源: Taylor

摘要:

Studies on the rate of the reaction of substituted dimethylaniline N-oxide (DMAO) with substituted benzoic anhydride (Bz2O) and the rate of polymerization of methyl methacrylate (MMA) with their systems were made. The solvent effects on the rate of the reaction of DMAO with Bz2O and on the polymerization of MMA with the system were also studied.

ISSN:0022-233X    

DOI:10.1080/00222336808053348

出版商:Taylor & Francis Group    

年代:1968

数据来源: Taylor

摘要:

It was described in the literature that p-methoxy-p′-nitrobenzoyl peroxide decomposed homolytically in benzene, but heterolytically in acetone. However, in the present study the polymerizations of styrene and acrylonitrile were found to proceed always through radical mechanism in benzene, dimethylformamide, or acetone. And in the above various solvents, the rate of polymerization was found to be almost equal.

ISSN:0022-233X    

DOI:10.1080/00222336808053349

出版商:Taylor & Francis Group    

年代:1968

数据来源: Taylor

摘要:

Starch-polyacrylonitrile graft copolymers prepared in a number of aqueous-organic solvent systems with ceric ammonium nitrate as the initiator had more grafted chains than those prepared in water alone, and these were of lower molecular weight. Substitution of methanol for 80% of the water produced grafted chains with a molecular weight of 15,700 and a grafting frequency of 253 anhydroglucose units per graft. The influence of catalyst concentration, increased reaction temperature, and sodium sulfate on the composition of the copolymer were investigated for the methanol-water system.

ISSN:0022-233X    

DOI:10.1080/00222336808053350

出版商:Taylor & Francis Group    

年代:1968

数据来源: Taylor

摘要:

Solvent-modified (toluene) copolymers have been prepared from styrene cross-linked with commercial divinylbenzene, m-divinylbenzene, and p-divinylbenzene at divinyl monomer contents of 16 mole % and 32 mole % at FM= 0.50. The resultant copolymers have been characterized by swelling-ratio determinations and rates of sulfonation at 60 and 80°C. The solvent-modified 16 mole % cross-linked copolymers sulfonated at rates slightly greater than those characterizing the 8 mole % cross-linked copolymers prepared in the absence of diluent. The order of decreasing sulfonation rates for both the conventional 8 mole % cross-linked systems and for the solvent-modified 16 mole % cross-linked copolymers is commercial divinylbenzene/styrene, p-divinylbenzene/styrene, m-divinylbenzene styrene. The 32 mole % cross-linked systems exhibit a different order of decreasing sulfonation rates: commercial divinylbenzene/styrene, m-divinylbenzene/styrene, p-divinylbenzene/styrene. The swelling ratios of the 32 mole % solvent-modified copolymers were comparable to those of the conventional 8 mole % cross-linked systems.

ISSN:0022-233X    

DOI:10.1080/00222336808053351

出版商:Taylor & Francis Group    

年代:1968

数据来源: Taylor

摘要:

Measurements of shrinkage temperatures (TS) for fibrous collagen, of equilibrium degree of swelling (v−1) for the same in the amorphous state, and of intrinsic viscosity ([η]) for randomly coiled gelatin are reported. The data were obtained for a large variety of salts which are typical representatives of lyotropic series. The order of anions and cations for decreasing TSand increasing both v−1and [η] (generally, for increasing salting in) is F−< SO2-4< acetate < Cl−< Br−< NO−3< I−< SCN−and K+< Mg2+< Na+< Cs+< Li+< Ca2+. For salts of ions at the extreme left of the series (salting-out agents) the shrinkage temperature in solutions of different salt concentration (CS) is controlled by the amount of diluent in equilibrium swelling with the molten network, and the shape of TSvs. CScurves can be represented by conventional theories valid for binary polymer diluent systems based on a lattice model with a single interaction parameter. In such cases the salt-water solution behaves as a single component diluent and its effect on the measured properties is described as a diluent effect.

ISSN:0022-233X    

DOI:10.1080/00222336808053352

出版商:Taylor & Francis Group    

年代:1968

数据来源: Taylor