摘要:

AbstractBase membranes were prepared by coating a monomer mixture consisting of styrene–divinylbenzene–polybutadiene–t‐amyl alcohol onto a polypropyrene cloth and subsequently by polymerizing the monomers. The resultant base membranes were chloromethylated and then quaternized. Thus, macroreticular anion exchange membranes were prepared and their properties were investigated. Furthermore, the organic fouling of the membranes was studied by using Na dodecylbenzenesulfonate as a foulant. The resistibility of the membranes was dependent on the balance between the porosity of the membranes and the foulant q

ISSN:0021-8995    

DOI:10.1002/app.1976.070201201

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1976

数据来源: WILEY

摘要:

AbstractBecause hydrophilic copolymers containing cyanacrylate elements should be useful as components of adhesives in surgery, the conditions of grafting of ethyl α‐cyanacrylate on poly(vinyl alcohol) were studied. Two anthraquinone derivatives were applied as sensitizers in UV‐initiated grafting; 2,6‐disulfoanthraquinone sodium salt proved to be especially efficient. IR spectra and derivatograms of poly(vinyl alcohol‐g‐ethyl α‐cyanacrylate)

ISSN:0021-8995    

DOI:10.1002/app.1976.070201202

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1976

数据来源: WILEY

摘要:

AbstractThe temperature dependence of the dynamic modulus (E′) and the mechanical loss tangent (tanδ) of amorphous cellulose prepared from cellulose triacetate by saponification was measured and compared with that of cellophane, recrystallized cellulose obtained by immersing amorphous cellulose in water, and cellulose triacetate. TheE′ of amorphous cellulose decreased initially with increasing temperature and then began to increase at about 70°C with a maximum at 80°C, decreasing again at about 100°C. Another decrease inE′ was observed at 220°C accompanied by a discontinuity at 155°C. In the tan δ‐versus‐temperature curve, a medium peak at 60°C a shoulder peak at 146°C, and a broad peak at 200°C were observed. It was found that the transition at about 60°C was related to hydrogen bond formation by free OH groups. The transition at about 150°C was attributed to a recrystallization process by heating, and the relaxation at 200°C, to the glass transition of the polymer. The decrement inE′ observed at about 100°C was attributed to the cooperative motion of an individual pyranose ring in amorphous cellulose, juding from theE′ and tan δ assignment of other cellulose materials. The change inE′ was also measured isothermally as a function of time in the temperature range between 40°C and 80°C, where a maximum in tan δ and an increment inE′ were observed as the temperature dependence of the dynamic viscoelasticity. The change inE′ with elapsed time was analyzed kinetically, and an activation energy of 2.6 kcal/mole was calculated. This value is the expected activat

ISSN:0021-8995    

DOI:10.1002/app.1976.070201203

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1976

数据来源: WILEY

摘要:

AbstractThe radiation‐induced polymerization of acrylamide was studied to prepare a high molecular weight and highly effective polyacrylamide flocculant. Among various solvents, mixtures of water–tert‐butyl alcohol and water–acetone were found to be suitable for the synthesis of the high molecular weight polyacrylamide. For polymerization in acetone–water mixtures, the molecular weight of polymer increases with monomer concentration; but at the high concentration, intermolecular imidation of amide groups tends to take place during the polymerization to from crosslinked and water‐insoluble polymer. The water‐soluble polymer with the largest molecular weight of 6.7 × 106is produced in the polymerization with monomer concentration of 2.91 moles/1. at 0°C at a dose rate of 6.2 × 102rad/hr in acetone–water mixture containing 60 vol‐% water. The crosslinking of polymer of the formation of water‐insoluble polymer could be avoided by the addition of K2CO3or NaOH to raise the pH of the reaction mixture above 6.5. The flocculation effects were evaluated from sedimentation speed of kaolin suspension and transparency of the separated water. The sedimentation speed is proportional to the intrissic viscosity of the polymer in the range of 4 to 23 dl/g. The polymers prepared in this study show much higher sedimentation speed than commercial polyacrylamide flocculants. The transparency of the separated water is higher than 93%, similar to the results with

ISSN:0021-8995    

DOI:10.1002/app.1976.070201204

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1976

数据来源: WILEY

摘要:

AbstractThe objective of this work was to obtain primary amine groups on the surface of poly(vinyl alcohol) films by means of a reaction with hexamethylene diisocyanate. The reaction was run in such a way as to minimize the internal crosslinking by employing a large excess of hexamethylene diisocyanate in toluene and then hydrolyzing the unreacted isocyanate endgroup to primary amine. After dialyzing out the adsorbed hexamethylenediamine from the aqueous solution of reacted poly(vinyl alcohol), the extent of covalent bonding of hexamethylene diisocyanate onto the polymer was determined by measuring aminohexyl content through a fluorescence assay. This assay is based on the reaction of fluorescamine, 4‐phenylspiro[furan‐2(3H)‐1′‐phthalan]‐3,3′‐dione, with a primary amine to yield a fluorophor which will emit a strong fluorescence at 475–490 nm when excited at 390 nm. Analyses show a range of 1.1 × 10−10−3.6 × 10−10mole of amines per cm2of reacted poly(vinyl alcohol) film. When assuming 47% as degree of crystallinity approximated by IR spectroscopy for these polymer films, the availability of hydroxyl groups in amorphous region was estimated to be 3.7 × 10−10mole/cm2. The extent of reaction based on available hydroxyl groups was then in the range of 31–97%. The primary amine groups attached by this method can now be exploited for binding biomolecules such as heparin (anticoagulant) or fibrinolytic enzymes in an attempt to a

ISSN:0021-8995    

DOI:10.1002/app.1976.070201205

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1976

数据来源: WILEY

摘要:

AbstractThe diffusion of Direct Blue 76 dye in aqueous dilute polymer solutions was studied using the capillary method. The polymer systems studied included dilute solution of carboxymethyl cellulose, poly(ethylene oxide), and polyacrylamide. It was found that the diffusion coefficient of Direct Blue 76 in carboxymethyl cellulose is higher than that in pure water, while in polyacrylamide and poly(ethylene oxide) solutions the value is lower than that in pure water. The diffusion coefficient of Direct Blue was found to decrease with increasing polymer concentration in case of poly(ethylene oxide) and polyacrylamide, while in case of carboxymethyl cellulose the diffusion coefficient increases with polymer concentration. The effect of temperature on the diffusion coefficient of Direct Blue 76 in the three polymers was found to obey the Arrhenius equation. The activation energy for diffusion of Direct Blue 76 in water, poly(ethylene oxide), polyacrylamide, and carboxymethyl cellulose was found to be 4.38, 7.7, 5.44, and 5 kcal, respectively, for polymer concentration of 0.25 g/l.

ISSN:0021-8995    

DOI:10.1002/app.1976.070201206

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1976

数据来源: WILEY

摘要:

AbstractCarboxylated polystyrene latexes have been prepared by copolymerizing acrylic acid at the appropriate degree of neutralization in the absence or presence of sodium dodecyl sulfate (SDS), and the particle formation process was investigated from the number and uniformity of particles. In the absence of SDS or in a concentration range of SDS lower than 6.41 mmole/l., the formation of particles can predominantly be attributed to the precipitation of growing radicals formed in the aqueous phase; whereas in a concentration range of SDS higher than 6.41 mmole/l., the formation of particles can predominantly be attributed to the initiation of polymerization in the interior of SDS micelles containing solubilized styrene by the collision of growing radicals formed in the aqueous phase. In the former range, the number of particles increases linearly with increasing concentration of SDS below the critical concentration of 1.60 mmole/l., which is sufficient to stabilize particles formed by the precipitation of growing radicals, and remains constant above the critical concentration. The effect of initiator concentration as well as amount of styrene on the formation of particles also supports the particle formation process described above.

ISSN:0021-8995    

DOI:10.1002/app.1976.070201207

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1976

数据来源: WILEY

摘要:

AbstractSoap‐free carboxylated polystyrene latexes have been prepared by copolymerizing acrylic acid (AA) in a wide range of degree of neutralization using a slight amount of soap, and the particle formation process was investigated from the number and uniformity of particles. It was found that the degree of neutralization of AA as well as the amount of AA have a great effect on the formation of particles. On the basis of the calculation results of the composition of the growing radical formed in the aqueous phase at the initial stage of the polymerization, the results can reasonable be explained by a change in the hydrophilic nature of growing radicals formed in the aqueous phase at the initial stage of the polymerization, the results can reasonably be explained by a change in the hydrophilic nature of growing radicals which are formed in the aqueous phase and precipitate out to form particles. It was also established that the introduction of α‐methylstyrene or methyl methacrylate has a great effect on the formation of particles, which is consistent with the above‐described consider

ISSN:0021-8995    

DOI:10.1002/app.1976.070201208

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1976

数据来源: WILEY

摘要:

AbstractBisphenol fluorenone carbonate–dimethylsiloxane block polymers have been synthesized by interfacial condensation of phosgene with various mixtures of BPF‐endcapped silicone oligomers and free BPF or its monosodium salt. The multisequence block polymers described here contain 7% to 27% silicone consisting of blocks of number‐average degree of polymerization 10 to 40. Cast films are clear and colorless. Two glass temperatures are evident in each resin, one at about −100°C for the silicone microdomains and one at temperatures as high as 275°C for the polycarbonate matrix. While BPF polycarbonate is brittle, block polymers with as little as 10% silicone yield by shear deformation before breaking. Ultimate elongations are increased by preorientation at silicone contents above 15%. At temperatures far removed from BPF carbonate domainTg's, both modulus and yield stress decrease with increasing silicone content, independent of block length, in a manner rationalized quantitatively by hard phase–soft phase continuum models. Ultimate tensile elongation, impact toughness, and plane strain stress intensity factors increase with silicone content, through a stress whitening mechanism. At higher silicone contents, shear deformation enhances tensile elongation and impact toughness. Heat distortion temperatures of 200°C or more are achieved. Flame resistance exceeds that of any known nonhalogenated resin. The resins are extrudable and injection moldable with only minor changes in color, transparency, and strength properties. Resins with 15% to 20% silicone can have a balance of properties that makes them attractive as tough, transparent heat‐ and flame‐ resistant engi

ISSN:0021-8995    

DOI:10.1002/app.1976.070201209

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1976

数据来源: WILEY

摘要:

AbstractThe carbonyl species present in oxidized polyethylene are qualitatively and quantitatively determined through the use of infrared measurements on the polymer. The method described makes use of a carbon monoxide/ethylene copolymer wedge in the reference beam of the infrared spectro photometer to compensate the large 1720 cm−1ketone absorbance. This allows one to observe the 1710 cm−1and 1735 cm−1carbonyl absorbances as distinct peaks rather than as shoulders on the 1720 cm−1peak. This is a significant advantage over other published infrared methods for this analysis. The absorbances obtained at 1710 cm−1and 1735−1are then used in an equation to calculate the absorbance at 1720 cm−1due to ketonic carbonyl only. Our results confirm Cooper and Prober's assignment of both the 1710 cm−1and 1735 cm−1absorbances in the infrared spectra of oxidized polyethylene to acid functionality. Our quantitative results are comparable to those reported by Cooper and Prober, and our method represents a significant reduction in the time required for the analysis (1.5 hr vs. ∼45 days). The carbonyl distribution in a commercially oxidized polyethylene wax was determined as being ∼11.0 ketone CO/2000 C and ∼21.7 acid CO/2000 C (with a σ of 1.8 CO/2000 C and 3.0 CO/2000, respectively). A high‐density polyethylene, oxidized with air in the laboratory, contained ∼1.91 ketone CO/2000 C and 2.19 acid CO/2000 C (with a σ of 0.08 C

ISSN:0021-8995    

DOI:10.1002/app.1976.070201210

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1976

数据来源: WILEY