摘要:

2-Hydroxypropyl methacrylate (2 HPMA) has been copolym-erized with ethyl methacrylate (EMA), n-butyl methacrylate (BMA), and 2-ethylhexyl methacrylate (EHMA) in bulk at 60°C using benzoyl peroxide as initiator. The copolymer composition has been determined from the hydroxyl content. The reactivity ratios have been calculated by the YBR method. For copolymerization of 2-HPMA (M1) with EMA (M2), the reactivity ratios are: r1=1.807 ± 0.032, r2=0.245 ± 0.021; with BMA (M2) they are r1=2.378 ± 0.001, r2=0.19 ± 0.01; and with EHMA the values are r1=4.370 ± 0.048, r2=0.103 ± 0.006. Since the reactivity ratios are the measure of distribution of monomer units in a copolymer chain, the values obtained are compared and discussed. This enables us to choose a suitable copolymer for synthesizing thermoset acrylic polymers, which are obtained from cross-linking of hydroxy functional groups of HPMA units, for specific end uses.

ISSN:0022-233X    

DOI:10.1080/00222338108063236

出版商:Taylor & Francis Group    

年代:1981

数据来源: Taylor

摘要:

The graft copolymerization of methyl methacrylate onto wool fibers was investigated in aqueous solution using the acetylacetonato complex of manganese(III). The rate of grafting was determined by varying the monomer, the complex, the temperature, the acidity of the medium, the nature of the wool, and the reaction medium. The graft yield increases with increasing monomer and complex concentrations. The graft yield also increases with increasing temperature. The grafting is considerably influenced by chemical modification of wool prior to grafting. A suitable mechanism has been proposed and a rate equation has been derived.

ISSN:0022-233X    

DOI:10.1080/00222338108063237

出版商:Taylor & Francis Group    

年代:1981

数据来源: Taylor

摘要:

The thermal properties of dehydrochlorinated PVC (DHPVC) were evaluated. From thermogravimetric analysis (TGA) and differential thermal analysis (DTA), a larger decrease in thermal stability of dehydrochlorinated PVC than of PVC was observed. Thermal stability of DHPVC increased continuously with an increase in dehydrochlorination temperature and dilution of the reaction solution during dehydrochlorination. However, with an increase in dehydrochlorination time, an increase in thermal stability after an initial drop was obtained. The highly cross-linked product separated from the reaction solution at higher dehydrochlorination temperatures showed a lower thermal stability than that of corresponding soluble DHPVC. The stress-strain behavior of dehydrochlorinated PVC samples was also studied.

ISSN:0022-233X    

DOI:10.1080/00222338108063238

出版商:Taylor & Francis Group    

年代:1981

数据来源: Taylor

摘要:

p-Aminosalicylic acid (PAS) was condensed with formaldehyde in the presence of aqueous oxalic acid and aqueous sodium hydroxide. The polymer sample (PAS-F,1) obtained withacid catalyst was characterized by IR spectral study, by its Mndetermined by nonaqueous conductometric titration both against standard acid and alkali, by viscometric study in formic acid, and by DTA. The IR spectral and general characteristics of a polymer sample (PAS-F,2) prepared in the presence of aqueous alkali resemble those of a polymer sample (AP-F) prepared similarly from m-aminophenol and formaldehyde, indicating decarboxylation of PAS during the base-catalyzed polymerization of PAS with formaldehyde. Polymeric metal chelates of Fe(III), Cu(II), Zn(II), and Mn(II) ions with the PAS-F,1 polymer sample have been prepared and characterized by elemental analyses, IR spectral study, measurements of magnetic moments, and thermal analyses. Chelation ion-exchanging properties of the PAS-F,1 polymer sample have also been studied employing the batch equilibration method.

ISSN:0022-233X    

DOI:10.1080/00222338108063239

出版商:Taylor & Francis Group    

年代:1981

数据来源: Taylor

摘要:

The mean hydrodynamic radius of poly(p-isopropyl α-methylsty-rene) in toluene has been determined at 21.5° C as a function of weight-average molecular weight Mwfrom 18,000 to 625,000 dalton. The measurements of hydrodynamic radii were made using photon correlation spectroscopy with a convenient specially designed filtering system to remove dust from the samples. The coefficients in the relationship D=CM−ahave been determined for our polydisperse samples. Although the polydispersity severly affects the determination of C, we have determined a=0.57 ± 0.03 in agreement with theories for linear chains in good solvent. We also report the first determinations of the Huggins coefficients for poly(p-isopropyl α-methylstyrene).

ISSN:0022-233X    

DOI:10.1080/00222338108063240

出版商:Taylor & Francis Group    

年代:1981

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:10.1080/00222338108063225

出版商:Taylor & Francis Group    

年代:1981

数据来源: Taylor