摘要:

AbstractA soluble and self‐crosslinkable linear copolymer with pendant epoxy and pyridyl groups was obtained from glycidyl methacrylate (M1) and 2‐vinylpyridine (M2) or 2‐vinyl‐5‐ethylpyridine (M2) by the action of azobisisobutyronitrile. The monomer reactivity ratios were determined in tetrahydrofuran at 60°C:r1= 0.510,r2= 0.620 with 2‐vinylpyridine andr1= 0.57,r2= 0.62 with 2‐vinyl‐5‐ethylpyridine. These were consistent with the calculated values with the reportedQandevalues for these monomers. The intrinsic viscosities of the copolymers with 2‐vinylpyridine and with 2‐vinyl‐5‐ethylpyridine were found to be 0.17–0.19 and 0.26–0.38, respectively, in tetrahydrofuran at 30°C; they were independent of the copolymer composition. The copolymers were amorphous, had no clear melting points, and became insoluble crosslinked polymers under heating without furthe

ISSN:0360-6376    

DOI:10.1002/pol.1975.170130501

出版商:John Wiley&Sons, Inc.    

年代:1975

数据来源: WILEY

摘要:

AbstractThe kinetics of the radiation‐induced bulk polymerization of vinyl chloride in the early stages was determined in the temperature range of −30 to 50°C and dose rates varying from 0.6 to 17 rad/sec by the dilatometric method. Some runs of polymerization of vinyl chloride added with different percentages of tetrahydrofuran were also carried out. The results were found to agree with those previously obtained with polymerizations carried out to high conversions. The results are discussed on the assumption of a decrease in the extent of swelling of the polymer by monomer with decreasing polymerization temperature. By comparison with the data of other precipitating polymerization systems the possibility of a generalized interpretation for the heterophase polymerization is exam

ISSN:0360-6376    

DOI:10.1002/pol.1975.170130502

出版商:John Wiley&Sons, Inc.    

年代:1975

数据来源: WILEY

摘要:

AbstractThe polymerization of vinylferrocene in benzene at 60°C in the presence of 2,2′‐azobisisobutyronitrile has been studied. Densities and apparent densities were determined and rates of polymerization measured dilatometrically. The results show that vinylferrocene does not obey normal vinyl polymerization kinetics. Thus the rate of polymerization is proportional to the mean monomer and mean initiator concentrations both raised to a power of 1.1, and the degree of polymerization is independent of the initiator concentration. The polymerization reaction also has a high overall activation energy of 139 kJ/mole. The unusual kinetics are due to a monomolecular termination of the polyvinylferrocene chain radical which is also intermolecular with respect to the chain radical. Termination occurs by an intramolecular electron transfer reaction from a ferrocene nucleus to the growing chain radical which deactivates the chain radical and produces a polymer molecule containing a high spin Fe (III) complex. The presence of this species has been confirmed by Möussbauer and ESR spectroscopy. The rate constant for termination is between 3 and 60 sec‐1. Intramolecular electron transfer has not been previously observed in vinyl polymerizations. The term “intralectran” is suggested to describe this new type of termination. Vinylferrocene readily undergoes transfer to monomer (with a transfer constant equal to about 8 × 10‐3) and to polymer, but

ISSN:0360-6376    

DOI:10.1002/pol.1975.170130503

出版商:John Wiley&Sons, Inc.    

年代:1975

数据来源: WILEY

摘要:

AbstractThe effect of CS2on isoprene polymerization with triisobutylaluminum‐titanium tetrachloride catalysts was studied at Al/Ti ratios of optimum (0.9) and higher values. In the absence of CS2, appreciable amounts of low molecular weight oils (“extractables”) were formed at the expense ofcis‐1,4‐polyisoprene with higher than optimum Al/Ti ratios. Small amounts of CS2were found to prevent extractables formation and allow attainment of higher yields ofcis‐1,4‐polyisoprene. The optimum CS2/Ti chloride molar ratio (0.1) was independent of the Al/Ti ratio of the catalyst. Polymer microstructure and dilute solution viscosity were unaffected by CS2. The results support the theory that the catalyst surfaces hold two types of active sites: p‐sites, which initiate polymerization, and o‐sites, which lead to oligomerization. CS2appears to enhance polymerization by coordinating selectively at the o‐sites. The predominance of oligomerization at the higher Al/Ti ratios was attributed to a destruction of p‐sites by exc

ISSN:0360-6376    

DOI:10.1002/pol.1975.170130504

出版商:John Wiley&Sons, Inc.    

年代:1975

数据来源: WILEY

摘要:

Abstract1,3‐Bis(p‐phenoxybenzenesulfonyl)benzene, 4,4′‐bis(p‐phenoxybenzenesulfonyl)diphenyl ether, and 4,4′‐diphenoxydiphenyl sulfone were polymerized with isophthaloyl or terephthaloyl chlorides in Friedel‐Crafts type polymerizations. These polymers had [2,2]p‐cyclophane units in the backbone, introduced by employing 3,9‐bis(p‐phenoxybenzoyl) [2.2]p‐cyclophane as part of the polyaryl ether component. Thermolysis of the dimethylene bridge of the [2.2]p‐cyclophane monomer produced diradicals which combined across polymer chains to provide crosslinks.p‐Cyclophane polymers with 1,3‐bis‐(p‐phenoxybenzenesulfonyl)benzene showed potential as high performance, t

ISSN:0360-6376    

DOI:10.1002/pol.1975.170130505

出版商:John Wiley&Sons, Inc.    

年代:1975

数据来源: WILEY

摘要:

Abstract1,3‐Bis(p‐phenoxybenzenesulfonyl)benzene and 4,4′‐diphenoxydiphenyl sulfone were polymerized with isophthaloyl and terephthaloyl chloride in Friedel‐Crafts type polymerizations. These polymers had 2,4‐diphenoxyacetophenone in the backbone. The acetyl group was then converted into an acetylene group. They were crosslinked effectively by cyclization of the acetylene groups with a catalyst or by cyclo‐addition with bisn

ISSN:0360-6376    

DOI:10.1002/pol.1975.170130506

出版商:John Wiley&Sons, Inc.    

年代:1975

数据来源: WILEY

摘要:

AbstractPolyamides fromn‐alkylmalonic acids and linear aliphatic diamines, with paraffinic side chains of 3–18 carbon atoms, were prepared by melt polycondensation or by low‐temperature interfacial polycondensation and were characterized by infrared, differential scanning calorimetry (DSC), and x‐ray diffraction techniques. First‐order transitions were found in the range of 130–210°C, depending on the number of carbon atoms in the side chain. The x‐ray diffraction indicated substantially amorphous systems for polyamides with 8–18 carbon atoms in the side chain. However, long‐range order arises in these polymers from a solid‐state structure in which polyamide and hydrocarbon layers having partially disordered chain con

ISSN:0360-6376    

DOI:10.1002/pol.1975.170130507

出版商:John Wiley&Sons, Inc.    

年代:1975

数据来源: WILEY

摘要:

AbstractStudies of olefin copolymers by inverse gas chromatography show that the method is suitable for determining the crystallinity of compositions where a linear extrapolation of density determinations is not applicable. Satisfactory estimates of crystallinity were obtained on ethylene copolymers with carbon monoxide and vinyl acetate and on an emulsifiable polyethylene wax. Studies were also made in which the columns were packed with physical mixtures of GC support and polyolefin powders, either obtained direct or ground from film samples. It was shown that good estimates of crystallinity could be obtained if suitable allowance is made for variance in peak retention time with flow rate, due to the relatively slow rate of diffusion of the probe molecule in polymer particles of large diameter (>100 μm). If smaller particles are used it is usually unnecessary to correct for flow rate effects. This extends the usefulness of the “molecular probe” technique to any polyolefin sample which can be ground to a fine particle size and eliminates the need for solution coating of the column pac

ISSN:0360-6376    

DOI:10.1002/pol.1975.170130508

出版商:John Wiley&Sons, Inc.    

年代:1975

数据来源: WILEY

摘要:

AbstractThe polymerization ofN‐ethyl‐2‐vinylcarbazole andN‐ethyl‐3‐vinylcarbazole by an anionic mechanism has been demonstrated. Polymerization reactions were monitored by ultraviolet/visible spectroscopy and λmaxand ε values for the propagating carbanions determined. The 2‐vinyl monomer exhibits all the features of a standard “living” polymer; the carbanion is stable at ambient temperatures and high molecular weight,M̄n≃ 106, narrow distribution polymers and block copolymers with styrene have been prepared. The carbanion from the 3‐vinyl monomer is much less stable and a clean polymerization can only be conducted at temperatures below ‐60°C. A comparison of the anionic polymerization characteristics of theN‐, 2‐, and 3‐vinyl carb

ISSN:0360-6376    

DOI:10.1002/pol.1975.170130509

出版商:John Wiley&Sons, Inc.    

年代:1975

数据来源: WILEY

摘要:

AbstractThe monomerstrans‐(R)(–)‐5‐phenyl‐1,3‐hexadiene (I) andtrans‐(R)(–)‐6‐phenyl‐1,3‐heptadiene (II) were prepared by dehydration of (R)(–)‐3‐acetoxy‐5‐phenyl‐1‐hexene and (R)(–)‐3‐acetoxy‐6‐phenyl‐1‐heptene, respectively. Monomers I and II were polymerized in heptane with three catalyst systems: γ‐TiCl3–Al(i‐Bu)3, VCl3–Alet3, andnBuLi. Polymers of identical structures were obtained with all three catalysts; according to infrared and NMR spectra, only the 1,4 structure was present. Acetone‐insoluble fractions of poly‐I and poly‐II have higher optical rotations than the corresponding monomers ([M]Dof poly‐I, ‐46.45°, of monomer I, ‐28.6°: [M]Dof poly‐II, ‐46.8°, of mon

ISSN:0360-6376    

DOI:10.1002/pol.1975.170130510

出版商:John Wiley&Sons, Inc.    

年代:1975

数据来源: WILEY