摘要:

AbstractA facile synthesis of poly(phenylene sulfide) (PPS), poly(2‐methylphenylene sulfide) (PMPS), and poly(2,6‐dimethylphenylene sulfide) (PDMPS) from the respective copper (I) bromothiophenoxides is described. Polymerization was effected in a 10:1 quinoline:pyridine mixture at atmospheric pressure and conditions optimized for the preparation of high‐molecular‐weight materials. The preparation of PPS in pyridine under pressure at 250°C has been investigated for comparative purposes. Yields and the properties of materials produced by solution polymerization are comparable to or better than those produced in the autoclave reaction. Properties have been investigated as a function of reaction time and molecular weight, and the deficiencies of the molecular‐weight assessment methods are discussed. PMPS and PDMPS have been similarly studied and their properties evaluated. The use of heat of crystallization determinations for molecular‐weight studies on PPS are described and critical

ISSN:0021-8995    

DOI:10.1002/app.1979.070240501

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

年代:1979

数据来源: WILEY

摘要:

AbstractA flocculant based on waste oligomers from the polycaprolactam production was synthesized by alkaline reduction with Ni/Al alloy. Both the reduced oligoamide and the sodium aluminate are precipitated by methanol. An oligomer, absorbed by a mineral carrier, is isolated as final product. The modified oligoamide was characterized by elemental analysis, IR spectra, and was shown to contain hydroxyl groups. The prepared flocculant may be used for the clarification of natural dilute (1%) clay suspensions and wastewaters. It accelerates the precipitation 35 times, giving a compact precipitate, which favors the decanting of the clarified liquid. The optimal concentration of the flocculant is 1.8 g/liter (corresponding to 0.06 g/liter oligomer).

ISSN:0021-8995    

DOI:10.1002/app.1979.070240502

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

年代:1979

数据来源: WILEY

摘要:

AbstractNew polyol containing aromatic rings was prepared from BHET, or BHET/ethylene glycol mixtures and adipic acid. In this new system, the kinetics of polyesterification were investigated and were shown to follow the kinetic equations proposed by Lin and his co‐workers which were obtained by modifying Flory's theory. Polyurethane elastomers were prepared by reacting these polyols and toluene diisocyanate (TDI) in DMF solution with NaCN as a crosslinking catalyst at room temperature. Their physical properties such as density, gel fraction, swelling ratio, mechanical properties, etc., were measured. High values of elastic modulus are due to the rigid segment of BHET. By varying the molar ratio of diisocyanate and polyester, polyurethanes with different crosslinking densities can be obtained. The relationship between physical properties and crosslinking density was shown to follow the general theory of rubber elasticit

ISSN:0021-8995    

DOI:10.1002/app.1979.070240503

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

年代:1979

数据来源: WILEY

摘要:

AbstractA series of poly(vinyl chloride)/poly(butadiene–co–acrylonitrile) interpenetrating polymer networks (IPNs), all having 50/(25–25) weight compositions, was synthesized in latex form. The latex particles were studied after each step of the two‐staged polymerization and after molding or casting. Transmission electron microscopy together with dynamic mechanical spectroscopy suggest a graded composition within the latexes, in which the poly(vinyl chloride) seed latex network I forms a core that is partially penetrated by the poly(butadiene–co–acrylonitrile) network II, yielding increased amounts of poly(butadiene–co–acrylonitrile) in the shell of the

ISSN:0021-8995    

DOI:10.1002/app.1979.070240504

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

年代:1979

数据来源: WILEY

摘要:

AbstractReverse osmosis separation of phenol in various alcoholic solutions using porous cellulose acetate membranes was investigated. The permeation behavior of phenol was measured for cellulose acetate membranes having various pore size distributions which were prepared by annealing at four different temperatures. Some differences were found between the aqueous and the alcoholic solutions in solute permeabilities and product rates. Membranes annealed at 90°C showed higher permselectivity than membranes annealed at lower temperatures. The pore character was classified into two types according to the relation of the product rate of 1‐propanol and that of water. It was found in a series of alcoholic solutions that the permeability of phenol, the product rate, and the apparent partition coefficient are closely related to the carbon number of the alcohols, but the values ofJv× η (ca. 1.25 × 10−4poise·m3/m2·day) and of the permselectivity coefficient (ca. 0.83) remain constant. The result was analyzed by using the three‐dimensional solubility parameter to obtain some information for the partition mechanism of solutes in aqueous and alcoholi

ISSN:0021-8995    

DOI:10.1002/app.1979.070240505

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

年代:1979

数据来源: WILEY

摘要:

AbstractPolyhydrazides are prepared by condensation of cyanuric chloride with dihydrazides of dibasic carboxylic acids and are sulfurized with phosphorus pentasulfide. Copolymers of acrylamide and dimethylacrylamide with divinylbenzene are also sulfurized with phosphorus pentasulfide. The sulfurized polymers adsorb mercuric ion. In order to incorporate thiocarbamide groups into a polymer matrix, methylolthioureas are condensed with polyethylenimine. The reactions are carried out in the solid state or in aqueous solution. In the former, water is distilled off from the solidified mixture of the reactants; in the latter, methylothiourea and polyethylenimine are allowed to react in the presence of sulfuric acid. The products are good mercuric ion adsorbents.

ISSN:0021-8995    

DOI:10.1002/app.1979.070240506

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

年代:1979

数据来源: WILEY

摘要:

AbstractA quick and safe identification method is shown for plasticizers in PVC using programmed‐temperature gas chromatography. Plasticizers were identified by their retention index values measured by using normal paraffins. Several stationary phases with quite different polarity are proposed: with silicone polymers (SE 30, OV 17, and QF 1) and a porous polymer such as Tenax. Operational conditions were optimized. The initial column temperatures was chosen at a low value of 100°C with the first three phases and 180°C for the fourth. The best rate of temperature increase with time seemed to be 10°C/min. The calculation method for retention values (temperature, time, indices) was chosen just because it needed no approximation. Thermodynamic values for the solution of plasticizers were measured by using isothermal chromatography with all the stationary phases. Our method allows the analyst to operational conditions (solvent, percent, temperature) for chromatography, to solve his own problem by making use of a pocket computer. Quantitative analysis of plasticizers was obtained with good accuracy after a previous extraction and the addition of normal paraffin as internal stan

ISSN:0021-8995    

DOI:10.1002/app.1979.070240507

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

年代:1979

数据来源: WILEY

摘要:

AbstractHighly oriented isotactic polypropylene with ultrahigh modulus was prepared by means of the zone drawing method proposed by Kiho and Asai. This method features heating a limited portion of the sample. The maximum value of modulus attained was 15 GPa, which corresponds to about half the crystal modulus along the molecular axis evaluated by the x‐ray method. Such an ultrahigh modulus was obtained for a sample of medium molecular weight by inducing necking in the heater and subsequently cooling the sample at lower temperature. The loss tangent peak with the initiation of micro‐Brownian motion of amorphous chains became progressively smaller and broadened more at higher temperatures with increasing draw ratio. Orientation function of the crystalc‐axis increased with draw ratio λ in the region below λ = 9, but reached a constant value, 0.995, in the region above λ = 9. The modulus increased with draw ratio in all ranges of the dr

ISSN:0021-8995    

DOI:10.1002/app.1979.070240508

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

年代:1979

数据来源: WILEY

摘要:

AbstractPhysical and chemical properties of alternating copolymers of methyl α,β,β‐trifluoroacrylate (MTFA; CF2CFCO2CH3) with α‐olefins such as ethylene, propylene, and isobutylene and their hydrolyzed copolymers were investigated. The original ester‐type copolymers are amorphous and hydrophobic. The copolymers, except for the MTFA–isobutylene copolymer, were found to be easily hydrolyzed in boiled NaOH–methanol aqueous solution to give hydrophilic fluoropolymers which contain nearly theoretical amounts of carboxyl groups. No chain scission takes place during the hydrolysis. The decomposition temperature of the original ester‐type copolymers is in the range of 347° to 379°C in nitrogen atmosphere, and the glass transition temperature is in the range of 21° to 76°C. Two steps of weight decrease, at around 100°C due to the removal of absorbed water and around 250°C due to the decomposition, were observed in the TGA curve of the hydrolyzed acid‐type copolymers. Both ester‐ and acid‐type copolymers were crosslinked by electron beam irradiation, while the MTFA–isobutylene copolymer was degraded. The tensile strength of the copolymers is in

ISSN:0021-8995    

DOI:10.1002/app.1979.070240509

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

年代:1979

数据来源: WILEY

摘要:

AbstractBivalent and trivalent metallic ions, respectively, accelerate and inhibit the reaction of phenols with formaldehyde. The catalytic effect of these metallic ions is equivalent, though more marked, to that of hydrogen ions, and it is due to their stronger charge. Metallic ions/phenols/formaldehyde complexes are formed. The stability of these complexes and mainly their rate of metal exchange in solution are the determining factors in the accelerating or retarding action. Identified stable chromium (III)–resorcinol–formaldehyde and chromium (III)–phenol–formaldehyde complexes have slow rates of metal exchange and inhibit the resorcinol–formaldehyde and phenol–formaldehyde reactions. The opposite is valid for lead (II), zinc (II), and other bivalent metallic ions. A scale showing the order of the accelerating effect of a series of metallic ions is given. The presence of polymeric complexes has also be

ISSN:0021-8995    

DOI:10.1002/app.1979.070240510

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

年代:1979

数据来源: WILEY