摘要:

Adduct polymer (PPGMA) prepared from polypropylene glycol and maleic anhydride was found to give stable inverted emulsions when mixtures of cement, water, and vinyl monomers were vigorously stirred in the presence of PPGMA. In this case, the carboxyl groups of PPGMA were neutralized with metal ions generated from the cement into neutralized PPGMA which acts as an effective W/O type emulsifier. The inverted emulsions containing cement gave a new type of polymer-cement composites by polymerization of the vinyl monomers and also by hardening of the cement. Water-free composites were easily obtained by removing evaporative water. The effect of cement on the physical properties of the water-free composites was remarkable. Further, the use of mixed fillers of cement and Al(OH)3was found to improve the flame-retardant properties of the composites; however, increasing the Al(OH)3content in the fillers resulted in a decrease in the physical properties. Generally, the composites have improved resistance to acid media in which the usual foamed hydrated cement is eroded.

ISSN:0022-233X    

DOI:10.1080/00222338408077241

出版商:Taylor & Francis Group    

年代:1984

数据来源: Taylor

摘要:

Curing of 4,4′-bismaleimido-diphenyl methane-4,4′ -diaminodi-phenyl methane (1:0.3 molar ratios) (BM-A) was carried out in the presence of vinyl ester-styrene resin. The BM-A could be cured at lower temperatures. The char yields of the cured resins depended on the percentage of bismaleimide-amine in the blend.

ISSN:0022-233X    

DOI:10.1080/00222338408077242

出版商:Taylor & Francis Group    

年代:1984

数据来源: Taylor

摘要:

The lignin fractions isolated by one- and multistage soda and sulfate cookings showed almost identical IR spectra, indicating the similarity of the lignin skeletal structure throughout the plant. However, the absorbances reveal some differences. Similarity of the spectra includes: 1) chelation and bonding of the hydroxyl groups. 2) Stretching vibration of C-H bonds in methyl, methoxyl, and methylene groups. 3) Stretching vibration of C≡N. 4) Carbonyl unconjugated β-ketone, conjugated acids, or esters at 1725 cm−1. There is no change in the intensity of absorption at this band from that at 1515 cm−1with the cooking stage. 5) Aromatic skeletal vibration at 1610 and 1515 cm−1, affected by ring substituents at 1425 cm−1. 6) The band at 1465 cm−1showed a higher intensity for soda and soluble kraft lignins than for insoluble kraft ones. 7) The band at 1370 cm−1, assigned to phenolic OH bending, is affected by the methoxyl group. 8) The absence of condensed guaiacyl and the presence of syringyl and uncondensed guaiacyl. Assignments for hardwood lignin are shown for soda and soluble kraft lignins of bagasse, while those for softwood lignin are shown for soda, soluble, and insoluble kraft lignins of Ricinus communis and for insoluble kraft lignin of bagasse. A relation exists between the carbohydrate's lignin and the band at 920 cm−1. Lignins from Ricinus communis are of higher guaiacyl to syringyl ratios than those from bagasse. The presence of C—S vibration and the absence of thiol groups for kraft lignins are indicated.

ISSN:0022-233X    

DOI:10.1080/00222338408077243

出版商:Taylor & Francis Group    

年代:1984

数据来源: Taylor

摘要:

Complexes of the monovalent bidentate 2-hydroxypropiophenone with trivalent La, Pr, Nd, Sm, Gd, Dy, Ho, and Er have been synthesized, and their magnetic and spectral characteristics are reported. The values of naphelauxetic ratio (β), percentage covalency parameter (δ), and bonding parameter (b½) have been calculated.

ISSN:0022-233X    

DOI:10.1080/00222338408077244

出版商:Taylor & Francis Group    

年代:1984

数据来源: Taylor

摘要:

New chelates of lanthanon with N-thioacetyl-N-phenylhydroxylamine have been prepared. The available data and physical properties of the chelates indicate the attachment of each rare earth ion to three molecules of ligand and four molecules of water. This is supported by elemental analysis and UV and IR absorption spectra.

ISSN:0022-233X    

DOI:10.1080/00222338408077245

出版商:Taylor & Francis Group    

年代:1984

数据来源: Taylor

摘要:

Esterification of polyethylene glycols by various carboxylic acids in high yield and high substitution levels is described. The esterification reaction is achieved by dicyclohexylcarbodiimide and catalyzed by dimethylaminopyridine. Rate measurements indicated that the reaction is complete after 2 h at room temperature.

ISSN:0022-233X    

DOI:10.1080/00222338408077246

出版商:Taylor & Francis Group    

年代:1984

数据来源: Taylor

摘要:

Aromatic/aliphatic regular copolyoxamides were prepared from aromatic diamine-oxamides and aliphatic diacid chlorides of various lengths of methylene groups by solution polymerization. The aromatic diamine oxamides, N,N′-bis(4-aminophenyl)oxamide and N,N′-bis(3-aminophenyl)oxamide were prepared and both were reacted with adipoyl chloride, suberoyl chloride, and sebacoyl chloride to form six new regular copolyoxamides. The polymers formed were soluble in sulfuric acid and also in some polar amide solvents. All copolyoxamides were high melting, with the meta-phenylene copolyoxamides melting from 346 to 373°C with decreasing length of the aliphatic diacid chloride, and the para-phenylene copolyoxamides decomposing prior to melting at near 400°C. The new polymers were characterized by UV spectrophotometry, differential scanning calorimetry, and thermal gravitational analysis.

ISSN:0022-233X    

DOI:10.1080/00222338408077247

出版商:Taylor & Francis Group    

年代:1984

数据来源: Taylor

摘要:

Three kinds of betaine-type polymers, which are macromolecular amphoteric electrolytes, were found to be able to polymerize vinyl monomers in aqueous solution through a radical mechanism without any further initiator. Betain-type polymers form hydrophobic areas (HA) in water. Vinyl polymerization commenced in the HA. The effect of the pH of the aqueous solution on polymerization was investigated.

ISSN:0022-233X    

DOI:10.1080/00222338408077248

出版商:Taylor & Francis Group    

年代:1984

数据来源: Taylor

摘要:

The cationic polymerization of styrene initiated by arsenic trichloride (AsCl3) in the presence of traces of acetic acid (co-catalyst) at -8, -4, and 0°C for 100 min using the dilatometric technique in an inert atmosphere yielded low molecular weight polymer. The rate of polymerization (Rp) is a direct function of the concentration of AsCl3, monomer, and polar solvent, but inversely proportional to the polymerization temperature and nonpolar solvent. Hydroquinone has no effect on RpVarious kinetic parameters have been evaluated and a kinetic scheme is proposed.

ISSN:0022-233X    

DOI:10.1080/00222338408077249

出版商:Taylor & Francis Group    

年代:1984

数据来源: Taylor

摘要:

Kinetics of the cationic polymerization of 1-substituted aziridines, such as 1-methoxycarbonylmethyl aziridine, 1-methoxycarbonylethyl aziridine, and 1-benzyl aziridine, initiated with 3-hydroxy-1-propane sulfonic acid sultone have been investigated, and the results are compared with the results of the polymerization of 1-β-cyanoethyl aziridine. The course of polymerization of 1-methoxycarbonylmethyl aziridine involved a termination reaction due to the reaction between the growing endgroup and the imino group in the polymer chain. On the other hand, the polymerizations of 1-methoxycarbonylethyl aziridine and 1-benzyl aziridine were terminated by a backbiting reaction with the formation of a piper-adinium ring on the polymer end. The propagation and termination constants were obtained at different temperatures, and the enthalpies of activation (ΔH*) and the entropies of activation (ΔS*) for this polymerization were calculated.

ISSN:0022-233X    

DOI:10.1080/00222338408077250

出版商:Taylor & Francis Group    

年代:1984

数据来源: Taylor