摘要:

The syntheses of poly(methylsiloxane)s containing 4-[S(-)-L-methyl-1 -butoxy] -4′-[p-(ω -alkan -1 -yloxy)benzoyloxy] -a-methylstilbene side groups containing 11-undecanyl (18), 8-octyl (19), 6-hexyl (20), and 3-propyl (21), of a poly[(50-55%)-methyl-co-(45-50%)-dimethylsiloxane] containing 4-[S(-)-2-methyl-1-butoxy]-4′-[p-(8-octan-1-yloxy)benzoyloxy]-α-methylstilbene side groups (22) and of a poly(methylsiloxane) containing a 1:1 molar ratio of 4-[S(-)-2-methyl-1 -butoxyl]-4′ -[p-(8-octan-1 -yloxy)benzoyloxy] -α-methylstilbene and 4-[S(-)-2-methyl-l -butoxyl-4′ -[p-(6-hexan-1-yloxy)-benzoyloxyl-α-methylstilbene side groups (23) are described. All polymers and copolymers were characterized by a combination of differential scanning calorimetry and thermal optical polarized microscopy techniques.18exhibits an enantiotropicSA, while19, 20, 21, and23display both enantiotropicsAandS*cmesophases.22exhibits only an enantiotropic s: mesophase. In addition, all polymers and copolymers exhibit sidechain crystallization. These results have demonstrated that extending the length of the rigid part of the mesogenic unit of 4-[S(-)-2-methyl-l-butoxy]-4′-(ω-alkan-l-yloxy)-α-methylstilbene to 4-[S(-)-2-methyl-l-butoxy]-4′ -[p-(ω-alkan-l -yloxy)benzoyloxy]-α-methylstilbene increases the tendency of the resulting poly(methylsiloxane)s toward polymesomorphism.

ISSN:0022-233X    

DOI:10.1080/00222339108054051

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor

摘要:

The radical graft polymerization of vinyl monomers from carbon black initiated by azo groups introduced onto the surface was investigated. The introduction of azo groups onto carbon black surface was achieved by three methods: the reaction of 2,2′-azobis[2-(2-imidazolin-2-yl)propane] (AIP) with (1) epoxide groups, which were introduced by the reaction of carbon black with chlorometh-yloxirane; (2) acyl chloride groups, which were introduced by the reaction of carboxyl groups on the surface with thionyl chloride; and (3) 3-chloroformyl-1-cyano-1-methylpropyl groups, which were introduced by the reaction of carbon black with 4,4′-azobis(4-cyanovaleric acid) and then thionyl chloride. The amount of azo groups introduced onto the surface by the above methods was determined to be 0.07-0.19 mmol/g. The graft polymerization of methyl methacrylate was found to be initiated by azo groups introduced onto the carbon black surface. During the polymerization, poly(methyl methacrylate) was effectively grafted onto carbon black through propagation of the polymer from the radical produced on the surface by the decomposition of the azo groups. The percentage of grafting using carbon black having azo groups introduced by method 1 increased to 40%. It was also found that the graft polymerization of several vinyl monomers such as styrene, acrylonitrile, and acrylic acid was initiated by the azo groups introduced onto the surface and the corresponding polymer was effectively grafted onto the surface. Furthermore, the effect of the amount of carbon black having azo groups on the graft polymerization was investigated.

ISSN:0022-233X    

DOI:10.1080/00222339108054052

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor

摘要:

In a 1983 paper in thisJournal (A19, 693), Ham questioned the existence of ternary azeotropes. A recent paper by Quella[Makromol. Chem., 190, 1445 (1989)J has criticized the earlier thesis, in part on the basis that Ham's “indications have certainly not encouraged the search for ternary azeotropes,” and on the basis of “further experimental results from other authors”. This paper responds to Quella, further develops evidence against ternary azeotropes, and, in addition, discusses pertinent terpolymer interactions in terms of terpolymerization probabilities and in terms of general monomer reactivities.

ISSN:0022-233X    

DOI:10.1080/00222339108054053

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor

摘要:

Small-sized albumin gel microspheres, MSs, containing 5-fluorouracil (5FU) with targeting moieties on their surfaces (average diameter: 1.5 μm) were prepared by the glutaraldehyde crosslinking method and suspension technique. Since galactose is known to interact specifically with the asialoglycoprotein receptor on hepato-cyte, the galactose residues were introduced on the surface of MSs as the targeting moieties forhepatomathrough polyethylene glycol (PEG) spacers. PEG spacers were employed to depress the immu-nogenicity of albumin, to keep the mobility of the galactose residues, and to heighten the distributive stability of the MSs in aqueous solution. It was confirmed by ESC A analysis that the PEG chains were introduced onto the surfaces of MSs. The amount of galactose residues introduced to MS were estimated to be 0.013 wt%. The intra-MSs aggregation was observed by the addition of Ricinus Communis Agglutinin I (RCA120) into the MS suspension, and then the aggregation of MSs was dissociated by addition of free lactose. Moreover, by incubation of the MSs with humanhepatomaHLE cells, the phenomena of MS's specific binding onto HLE cell surfaces and phagocytosis of MSs by HLE cells were observed. These results suggested that the galactose residues on the surface of MSs were recognized with the galactose receptors onhepatomacell surfaces. The release rate of 5FU from MSs was investigatedin vitroin physiological saline at 37OC. About 90% of encapsulated 5FU were found to be released from MSs through incubation for 8 h.

ISSN:0022-233X    

DOI:10.1080/00222339108054054

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor

摘要:

Polymeric nitrofuran derivatives have been synthesized by chemical modification of macroporous styrene-divinylbenzene copolymers with low molecular weight nitrofurans. The 5-nitrofuryl groups are covalently attached to the polymeric carrier by azomethine, ester, N-alkyl, and sulfamide links, respectively. Comparative hydrolysis studies and biological tests of the modified resins suggested that the polymeric carrier-bound nitrofurans are antimicrobially active. The polymeric nitrofurans have been characterized by IR and “C-solid-NMR spectroscopy”.

ISSN:0022-233X    

DOI:10.1080/00222339108054055

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor

摘要:

The molecular weight distributions of poly(ethylene terephthalate) fibers aminolyzed with selected primary amines (namely, methylamine, ethylamine,n-butylamine, and ethanolamine) were determined by using gel permeation chromatography. Initially the shape of the differential molecular weight distribution (DMWD) curve did not change although its peak shifted to lower molecular weights. As aminolysis continued, a shoulder appeared on the DMWD curve. Its appearance seemed to coincide with an increase in the density of the product. Ultimately, distinct molecular populations could be identified in the treated polymer depending on the severity of the aminolysis and the selectivity of the particular amine. The lowest is thought to represent primarily crystalline residues and has a peak molecular weight of 3400. The relations betweenMnand ultimate tenacity and breaking strain for the aminolyzed products were linear.

ISSN:0022-233X    

DOI:10.1080/00222339108054056

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor

摘要:

A series of poly(aryl ether-bissulfone)s were synthesized from bis-phenols, 4,4′-bis(4-chlorophenylsulfonyl)biphenyl, and 4,4′-bis(4-fluorophenylsulfonyl)biphenyl. The bishalide monomers were synthesized by reaction of 4,4′-bis(chlorosulfonyl)biphenyl with a suitable aryl halide. Potassium carbonate mediated reaction in di-methylacetamide gave high molecular weight polymers in excellent yield. The polymers are soluble in dipolar aprotic solvents. Unlike the corresponding monosulfone analogues, the poly(aryl ether-bissulfone)s exhibited poor solubility in chlorinated hydrocarbons. The glass transition temperatures of the polymers are among the highest known for poly(aryl ether)s (241-271 °C). In addition, the polymers exhibit excellent thermal stability and they produce clear, colorless tough films by solution casting or compression molding.

ISSN:0022-233X    

DOI:10.1080/00222339108054057

出版商:Taylor & Francis Group    

年代:1991

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:10.1080/00222339108054050

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor