摘要:

The cationic ring-opening polymerization of 3,3-bis(chloromethyl)-oxetane (BCMO) was found to initiate by acylium perchlorate groups on carbon black, introduced by the reaction of acyl chloride groups with silver perchlorate. It was confirmed that poly-BCMO propagated from carbon black and effectively grafted from the surface. The percentage of grafting of poly-BCMO increased with increasing conversion and reached about 50%. The grafting efficiency, however, decreased with the extent of polymerization. This suggests that ungrafted polymer formed by chain transfer at higher conversion. The activation energy of the polymerization was estimated to be 28.5 kJ/mol. Furthermore, acylium perchlorate groups on carbon black are able to initiate the copolymerization of BCMO with tetrahydrofuran (THF). Poly-(BCMO-co-THF)s of various compositions were grafted from the surface; depending on the propagation of the copolymer, the percentage of grafting was as high as about 40%. The poly-BCMO-grafted and poly(BCMO-co-THF)-grafted carbon black gave stable colloidal dispersions in organic solvents.

ISSN:0022-233X    

DOI:10.1080/00222338908052007

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor

摘要:

The composition of a low-molecular-weight fraction from plasma-polymerizedN,N'-bis(dimethylsilyl)tetramethylcyclodisilazane has been studied by gas chromatography/mass spectrometry. Identification of the separate components of this fraction based on the mass spectra revealed the presence of various monomer derivatives mostly having the general structure of aN-silyl-substituted cyclodisilazane skeleton. This strongly suggested that this structural unit displays a high resistance to plasma fragmentation and that it was incorporated as such into the polymer film. Mechanisms have been proposed for the elementary plasma reactions involved in the formation of the identified compounds.

ISSN:0022-233X    

DOI:10.1080/00222338908052008

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor

摘要:

A new activating reagent for amide condensation [(1,2,3-benzotriazine-4-one)-3-yl] diphenyl phosphate (BTDP), was prepared in good yield (88%) by the reaction of 3-hydroxy-1,2,3-benzotriazine-4-one with diphenyl phosphorochloridate in the presence of triethylamine (TEA) in tetrahydrofuran. Benzanilide was readily prepared with this reagent from benzoic acid and aniline at room temperature in a model reaction. The polycondensation of several aromatic dicarboxylic acids with aromatic diamines that have electron-donating substituents with BTDP in the presence of TEA inN-methyl-2-pyrrolidone proceeded at room temperature to form polyamides with inherent viscosities of 0.33–1.14 dL/g. However, polyamides from aliphatic dicarboxylic acids and diamines that carry electron-withdrawing substituents showed lower inherent viscosities than those from aromatic acids and amines with electron-donating substituents.

ISSN:0022-233X    

DOI:10.1080/00222338908052009

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor

摘要:

A series of wholly aromatic,para-linked, thermotropic polyesteramides has been synthesized from various aminophenols, 2-trifluoromethyl terephthalic acid, and 2,2′-trifluoromethyl-4,4′-biphenyl dicarboxylic acid. The polymers exhibit good solubility and, in most cases, low mesophase transition temperatures. Oriented films of these materials show a high degree of optical anisotropy. The infrared dichroic behavior of the amide carbonyl was used to calculate orientation as well as a new value for the angle of the ester carbonyl vibrational transition moment.

ISSN:0022-233X    

DOI:10.1080/00222338908052010

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor

摘要:

Small-angle neutron scattering (SANS) studies of polymers are no longer a rarity in polymer science. It is now widely appreciated that SANS can provide unique data which provide greater insight into polymer structural properties than otherwise obtainable. Nonetheless, the costs of the apparatus and special efforts that have to be taken to prepare necessary deuterated polymers mean that such experiments have to be designed with care to ensure that unambiguous data are obtained. There are now in existence several reviews on various aspects [1–4] of SANS studies of polymers; attention in this review is focused on multiphase polymer systems. However, newer aspects of SANS studies on homopolymers will also be discussed, and we begin by a necessarily brief survey of the relevant theoretical expressions.

ISSN:0022-233X    

DOI:10.1080/00222338908052011

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor

摘要:

Thermally stable poly(Schiff bases) synthesized from dicarbonyls and aromatic diamines have been reported by several investigators [1-4], and they are known for their semiconducting properties [5–9]. A diketone is used as starting dicarbonyl in only a few reports [10, 11]. Consequently, poly(Schiff bases) were synthesized from furil(2,2′-bis(furyl)α,β-dione) and various diamines. They were characterized by IR, thermal studies, and electrical conductivity as a function of temperature.

ISSN:0022-233X    

DOI:10.1080/00222338908052012

出版商:Taylor & Francis Group    

年代:1989

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:10.1080/00222338908052006

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor