摘要:

AbstractThe equilibrium constants for the complex formation between stannic chloride and methyl methacrylate were determined inn‐hexane–toluene solution at 0, −20, and −30°C by using the absorption band at 350 nm. Continuous variation plots at −20°C inn‐hexane based on the1H‐chemical shifts definitely show a 1:1 interaction between the coordinated methyl methacrylate and styrene or toluene. The magnitudes of the shifts for the four groups of protons in methyl methacrylate are found to be in a specific ratio in common with the 1:2 complex–styrene or ‐toluene system. The equilibrium constants for the ternary molecular complex formation between the 1:2 complex and styrene or toluene were determined inn‐hexane in the temperature range −50 to +20°C by use of the chemical shifts. The concentrations of the complex species in the alternating copolymerization solutions were estimated by use of the equilibrium constants. There is a linear relationship between the enthalpy and the entropy changes for the ternary molecular complex formation, which is governed by the enthalpy factor. The specificity of the interactions indicates a specific time‐averaged orientation of benzene ring to the coordinated methyl methacrylate. The effects of the coordination of methyl methacrylate to stannic chloride were discussed on the basis of resu

ISSN:0360-6376    

DOI:10.1002/pol.1974.170121201

出版商:John Wiley&Sons, Inc.    

年代:1974

数据来源: WILEY

摘要:

AbstractIsotactic polypropylene film was stretched in poly(ethylene glycol) at 140°C and its melting behavior was investigated by using a differential scanning calorimeter (DSC‐1B). The shape of the melting curve depends largely on the stretching ratio,v.A sample stretched to moderate extension (1

ISSN:0360-6376    

DOI:10.1002/pol.1974.170121202

出版商:John Wiley&Sons, Inc.    

年代:1974

数据来源: WILEY

摘要:

AbstractTo investigate the mechanism of radiation‐induced grafting in this system, the increase of monomer concentration in the polyethylene film in styrene vapor was evaluated by measuring the weight increase and formulated to beV([M∞] − [M]). The decay of radical concentration was also measured by ESR and the rate constant of the decay was determined. The alkyl type radical was affected only a little by styrene, while the allyl type radical was much affected by styrene. A new computer investigation method was proposed to clarify the reaction mechanism. The data obtained were substituted into differential equations and used to calculate the pattern of increase of the degree of grafting for the preirradiation method with reaction in the vapor phase. Results of these calculations suggest that only allyl type radicals induce grafting reactions and that the grafting reaction seldom occurs in the region of grafted polyst

ISSN:0360-6376    

DOI:10.1002/pol.1974.170121203

出版商:John Wiley&Sons, Inc.    

年代:1974

数据来源: WILEY

摘要:

AbstractThe heterogeneous addition reaction of various monoepoxides with silk fibroins ofPhilosamia cynthia riciniandBombyx moriwas investigated at 45–75°C by use of aqueous solutions of various salts as padding catalysts. The effects of salt on the epoxide–silk fibroin reactions were attributed mainly to the nucleophilicity of the anions and also to the acidity or the electronegativity of the cations. The effect of the substituent of the epoxide on the add‐ons was elucidated by the modified Taft equation, (logW− logW0)/σ* = ρp+ ρsEs/σ*, whereW0andWare the add‐ons for the reaction of a given compound and of its substituted derivatives, σ* andEsare the polar and the steric substituent constants, ρpand ρsare the polar and the steric reaction constants, respectively. Histidine, lysine, arginine, tyrosine, serine, and acidic amino acids were found to react. The reactivity difference betweenPhilosamia cynthia riciniandBombyx morifibroins towards the epoxide was discussed in the light of the o

ISSN:0360-6376    

DOI:10.1002/pol.1974.170121204

出版商:John Wiley&Sons, Inc.    

年代:1974

数据来源: WILEY

摘要:

AbstractThe effects of γ‐irradiation (0.02–4.0 Mrad absorbed dose and 1.2 Mrad/hr dose rate) on depolymerization and selected physical properties of corn starch and amylose (both dry solid and solution forms) were investigated under conditions used to make graft polymers. Radiation introduces an alkali‐sensitive structure, most likely β‐alkoxycarbonyl, having aGvalue of 2.8. A dimethyl sulfoxide (DMSO)‐acetic acid‐water solvent for intrinsic viscosity was developed that degraded irradiated amylose less than did aqueous 90% DMSO. TheG(scission) value of 1.3 for solid amylose irradiated at 0°C under nitrogen is lower than most literature values for either amylose or other polysaccharides. The protection of amylose against irradiation degradation in water by additions of DMSO is noteworthy. TheG(scission) for amylose irradiated in 99.8% DMSO is 2.3; whereas, in

ISSN:0360-6376    

DOI:10.1002/pol.1974.170121205

出版商:John Wiley&Sons, Inc.    

年代:1974

数据来源: WILEY

摘要:

AbstractThe effect of ionization on the potentiometric and viscometric behavior of both poly(methacrylic acid) (PMA) and poly(acrylic acid) (PAA) was investigated in methanol–water mixtures. The potentiometric and viscosity data revealed that the conformational change which takes place for PMA in water gradually disappears with increasing content of methanol in methanol–water mixtures. For mixtures containing 40 and 50% methanol, the behavior of PMA solutions becomes similar to that of PAA, i.e., the discontinuity versus the degree of ionization is no longer detectable and the molecule unfolds regularly upon ionization. The addition of methanol leads to the breakdown of the compact structure of PMA which is stabilized, at low degree of ionization in water, by nonelectrostatic interactions between the methyl groups of

ISSN:0360-6376    

DOI:10.1002/pol.1974.170121206

出版商:John Wiley&Sons, Inc.    

年代:1974

数据来源: WILEY

摘要:

AbstractThe bulk and suspension polymerizations of vinyl chloride have been carried out in the presence of small known amounts of added oxygen at 54°C in the presence of peroxide initiators. The concentrations of oxygen were in the range 0–1240 ppm for 1‐gal bulk polymerization systems and 0–400 ppm for 15‐gal suspension polymerization systems. The thermal stabilities of the polymers prepared in the presence of oxygen were lower than those prepared under corresponding oxygen‐free conditions. The average molecular weights of bulk polymers isolated at relatively low conversions were reduced in the presence of oxygen, and the infrared spectra of the polymers were altered. The significance of the decreased thermal stabilities of the polymers prepared in the presence of oxygen is discussed briefly in relation to the possible sites of initiation of dehydroch

ISSN:0360-6376    

DOI:10.1002/pol.1974.170121207

出版商:John Wiley&Sons, Inc.    

年代:1974

数据来源: WILEY

摘要:

AbstractThe effect of ultraviolet irradiation on the terpolymerization was investigated. In the terpolymerizations of sulfur dioxide–butene‐1–acrylonitrile, sulfur dioxide–butene‐1–n‐butyl acrylate, and maleic anhydride–allyl chloride–acrylonitrile systems, the composition of the terpolymers prepared under ultraviolet irradiation was different from those prepared in the dark. The unit content of sulfur dioxide and butene‐1 or of maleic anhydride and allyl chloride in the terpolymer increased under ultraviolet irradiation. The nature of the growing end under ultraviolet irradiation is supposed to be the same as that of the dark polymerization on the basis of the same solvent effect on the terpolymer composition, the rate of polymerization and the molecular weight of polymer. The experimental results suggest that the complex between sulfur dioxide and butene‐1 or maleic anhydride and allyl chloride might be excited by ultraviolet light and the excited complex may participate in

ISSN:0360-6376    

DOI:10.1002/pol.1974.170121208

出版商:John Wiley&Sons, Inc.    

年代:1974

数据来源: WILEY

摘要:

AbstractThe copolymerization of vinylhydroquinone (VHQ) and vinyl monomers, e.g., methyl methacrylate (MMA), 4‐vinyl‐pyridine (4VP), acrylamide (AA), and vinyl acetate (VAc), by tri‐n‐butylborane (TBB) was investigated in cyclohexanone at 30°C under nitrogen. VHQ is assumed to copolymerize with MMA, 4VP, and AA by vinyl polymerization. The following monomer reactivity ratios were obtained (VHQ = M2): for MMA/VHQ/TBB,r1= 0.62,r2= 0.17; for 4VP/VHQ/TBB,r1= 0.57,r2= 0.05; for AA/VHQ/TBB,r1= 0.35,r2= 0.08. TheQandevalues of VHQ were estimated on the basis of these reactivity ratios asQ= 1.4 ande= −;1.1, which are similar to those of styrene. This suggests that VHQ behaves like styrene rather than as an inhibitor in the TBB‐initiated copolymerization. No homopolymerization was observed either under nitrogen or in the presence of oxygen. The reaction mechanism

ISSN:0360-6376    

DOI:10.1002/pol.1974.170121209

出版商:John Wiley&Sons, Inc.    

年代:1974

数据来源: WILEY

摘要:

AbstractThe decay behavior of cellulose radicals produced by photo‐irradiation at room temperature and the characteristics of photo‐irradiated cellulose samples to initiate graft copolymerization of methyl methacrylate (MMA) were investigated. ESR spectra of such untreated, swollen, oximated, and ferric ion‐sensitized samples irradiated at room temperature were constructed mainly of a single absorption line with a line width of 20 to 22 gauss and agvalue of 2.003, and it is surely conceivable that the radicals showing a singlet spectrum should agree with those of alkoxy end produced at either the C1or C4position of the glucose unit by the scission of glucosidic bonds. The decay of radicals was accelerated by contact of various solvents with the samples, the activity decreasing in the order, water ≈ methanol ≫ acetone>dioxane. On the other hand, the decay of radicals by vinyl monomers became smaller in the order, methacrylic acid>MMA ≈ styrene. Graft copolymerization of MMA by a photo‐irradiated sample was effectively initiated with the use of a certain amount of water or methanol, but not with acetone and dioxane. As no initiation can occur with the unirradiated sample, it is concluded that the initiation of graft copolymerization on the photo‐irradiated sample is attributable to cellulose radicals showing a singlet spectrum which are formed in photo‐irradiation at

ISSN:0360-6376    

DOI:10.1002/pol.1974.170121210

出版商:John Wiley&Sons, Inc.    

年代:1974

数据来源: WILEY