摘要:

Graft copolymerization of methyl methacrylate (MMA) on cellulose or oxycellulose gave a gross polymer product from which the free poly(methyl methacrylate) (PMMA) was easily separated by extraction with benzene. From the residue called the apparent graft copolymer, the unbound or free cellulose/ oxycellulose portion was separated from the cellulose/oxycellu-lose-PMMA graft copolymer portion by extracting the former with 4% aqueous NaOH following a xanthation process. The xanthation method allowed easy determination of efficiency of grafting with respect to cellulose/oxycellulose and degree of true grafting giving moles or moles of PMMA grafted per gram or per mole of cellulose/oxycellulose.

ISSN:0022-233X    

DOI:10.1080/00222338208082072

出版商:Taylor & Francis Group    

年代:1982

数据来源: Taylor

摘要:

Phenyliododichloride, C6H5IC12, can induce photopolymerization of methyl methacrylate almost instantaneously at 40°C under visible light. The initiator order and monomer order were 0.3 and close to 1.5, respectively, for [C6H5IC12] < 5.0 × lo−4mol/L while the corresponding values were 0 and 1.0, respectively, for [C6H5IC12] > 5.0 × 10−4mol/L. Kinetic and other data indicate a radical polymerization mechanism that involves complexation of a monomer molecule with C6H5IC12prior to the radical generation step. Termination appears to take place both by a bimolecular mechanism and by a degrada-tive initiator transfer mechanism at low [C6H5IC12], but it appears to take place almost exclusively by the latter mechanism when [CeH5ICl2] is high.

ISSN:0022-233X    

DOI:10.1080/00222338208082073

出版商:Taylor & Francis Group    

年代:1982

数据来源: Taylor

摘要:

Trioxane was copolymerized with small amounts of dioxolane in benzene in the presence of a boron trifluoride:a crylonitrile complex as initiator. The kinetics of reactions was expressed in terms of topoenergetic principles. The copolymerizations had no induction periods and the maximum reaction rate was found proportional to the square of both the initiator and monomers concentrations. A zwitterionic mechanism is suggested for initiation. The activation energy for the system with 5% dioxolane was determined as 18.3 kcal/mol. The melting behavior of the copolymers is briefly discussed as a function of the dioxolane initial content, and is indicative of the amorphous-crystalline coupling phenomenon. The copolymers with ∼ 5% dioxolane are thermostable in air up to 250%deg; and are recommended for practical purposes.

ISSN:0022-233X    

DOI:10.1080/00222338208082074

出版商:Taylor & Francis Group    

年代:1982

数据来源: Taylor

摘要:

The splitting of DSC melting endotherms of thermostable trioxane-dioxolane copolymers obtained with boron trifluoride: acrylonitrile complex as initiator, which were recorded before and after the annealing of samples at 140°C, was believed to result from an amorphous-crystalline coupling phenomenon brought about by noncrystallizable dioxolane fragments. Quantitative interpretations were made based on the total melting enthalpy and splitting factors after precipitation of dioxolane sequences as crystalline defects by annealing. The results obtained were compared with similar data registered for a commercial trioxane containing copolymer, namely Hostaform C.

ISSN:0022-233X    

DOI:10.1080/00222338208082075

出版商:Taylor & Francis Group    

年代:1982

数据来源: Taylor

摘要:

The glow discharge polymerization of a CF4/CH4mixture was investigated by using infrared spectroscopy and ESCA in comparison to the glow discharge polymerization of tetrafluoroethylene. The polymers prepared from a CF4/CH4mixture (70/30 molar ratio) as well as from tetrafluoroethylene possess low surface energy compared with that of conventionally polymerized polytetrafluoroethylene. The infrared spectrum of the polymer from a CF4/CH4mixture was fairly different from that of the polymer prepared from tetrafluoroethylene by glow discharge polymerization, which had an almost identical spectrum to that of conventionally polymerized polytetrafluoroethylene. Unanticipated residues included C˭C, C˭CF, C-F, NO2and C-O groups, O in addition to the expected C-F groups. The formation of these residues was discussed.

ISSN:0022-233X    

DOI:10.1080/00222338208082076

出版商:Taylor & Francis Group    

年代:1982

数据来源: Taylor

摘要:

This Symposium was held as a part of the American Chemical Society National Meeting. The Division of Colloid and Surface Chemistry was the prime sponsor and it was cosponsored by the Divisions of Organic Coatings and Plastics Chemistry, and Industrial and Engineering Chemistry. K. L. Mittal of IBM Corporation was the organizer and Chairman of this Symposium.

ISSN:0022-233X    

DOI:10.1080/00222338208082077

出版商:Taylor & Francis Group    

年代:1982

数据来源: Taylor

摘要:

This is a scanned image of the original Editorial Board page(s) for this issue.

ISSN:0022-233X    

DOI:10.1080/00222338208082061

出版商:Taylor & Francis Group    

年代:1982

数据来源: Taylor