摘要:

AbstractComposites of polypropylene—CaCO3coated with isopropoxy triisostearoyl titanate have been prepared on Buss Ko‐Kneader. These composites have been evaluated for mechanical properties, melt index, dispersion, and adhesion of polymer to filler using the scanning electron microscope. Calcium carbonate being a platelike substance with low aspect ratio results in composites having inferior tensile properties but superior impact characteristics. Uniform dispersion of filler in the composite and long alkyl chains of the coupling agent provide additional advantages such as improved melt index, higher tensile elongation, and better optical propert

ISSN:0021-8995    

DOI:10.1002/app.1982.070270111

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

年代:1982

数据来源: WILEY

摘要:

AbstractThe main role of the amino hydrogen bonding in the plasticization of water‐penetrated epoxy resins has been tested on a diglycidyl ether of bisphenol‐A (DGEBA) epoxy cured with different amounts of triethylenetetramine (TETA). Samples were characterized both by calorimetric and moisture diffusion techniques. The increased water solubilities and glass transition temperature depressions observed for the samples cured with an increased content of amino hardener were attributed to the high hydrophilic character of the amine. Theoretical models, based on the analysis of the free volume and entropy of the water saturated polymer, have been used to test the nature of the polymer‐diluent interactions. The comparison between the experimentally determined and theoretical values of the wet glass transition temperatures indicates how the free volume better describes the behavior of the low amino content resins while the entropy model become effective at increasing amino contents. Moreover, the actual water solubilities have been determined by thermal cycling of water‐saturated samples of different composition and used in the cited

ISSN:0021-8995    

DOI:10.1002/app.1982.070270112

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

年代:1982

数据来源: WILEY

摘要:

AbstractPoly(vinyl acetate) (PVAc) ofM̄w750,000M̄w/Mn3.85 andB̄n(the number of long branches per molecule) 2.2 was subjected to chain scission by mechanical (high‐speed stirring) as well as chemical (saponification and reacetylation) methods to investigate the effect of shear on the branching distribution. The extent of long branching was measured by gel permeation chromatography on‐line with low‐angle laser light scattering photometry. It was concluded that (i) the branches through the acetate group are long and are ruptured preferentially on shearing, (ii) the branches through the α‐ and β‐carbons are not broken on shearing, (iii) the extent of long branching through the acetate group is about 67% of total branching, and (iv) the poly(vinyl alcohol) derived from branched PVAc contains a smaller but nevertheless significant amoun

ISSN:0021-8995    

DOI:10.1002/app.1982.070270113

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

年代:1982

数据来源: WILEY

摘要:

AbstractIn order to understand the molecular behavior of polymers during flow through porous media, five polymers with varying degree of amide‐carboxylate group ratio in partially hydrolyzed polyacrylamides were selcted, and the flow properties of their dilute solutions were measured in unconsolidated porous media. It has been found that adsorption of the polymers at the surface during flow, which plays an important role in permeability reduction, largely depends on the flexibility of the linear chains and electrostatic nature of the porous matrix. The flexibility of the chain is explained on the nature and ratio of groups attached on linearCCChains, e.g., varying degree of NH2and COOH groups in partially hydrolyzed polyacrylamides in the exp

ISSN:0021-8995    

DOI:10.1002/app.1982.070270114

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

年代:1982

数据来源: WILEY

摘要:

AbstractThe particle size distribution of suspension copolymers of styrene, chloromethylstyrene, and divinylbenzene prepared with gelatin and poly(diallyldimethylammonium chloride) as suspension stabilizers can be varied widely by variation of the relative amounts of monomer and aqueous phases, the stirring speed, and the amount of added anionic surfactant sodium dodecylbenzenesulfonate.

ISSN:0021-8995    

DOI:10.1002/app.1982.070270115

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

年代:1982

数据来源: WILEY

摘要:

AbstractBlock copolymers composed of poly(dimethylsiloxane) segments linked to polypeptide have been synthesized by reacting primary amine‐terminated silicone withN‐carboxy anhydrides of amino acids. The amine‐terminated silicone was prepared by reacting “living” polysilanolate with γ‐aminopropyltriethoxysilane. The block copolymers prepared consisted of segments of poly(DL‐phenylalanine) or poly(γ‐benzyl‐L‐glutamate). The block copolymers were purified by extraction with solvents which are selective for the homopolymers. Analysis of the products was accomplished by hydrolysis of the polypeptide segments, infrared spectra, gel permeation chromatography, and elemental analysis. The content of the copolymers ranged from

ISSN:0021-8995    

DOI:10.1002/app.1982.070270116

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

年代:1982

数据来源: WILEY

摘要:

AbstractCrosslinked polymers based on the condensation of furfural withN‐vinylcarbazole and poly(N‐vinylcarbazole) were prepared. The effect of variation of furfural concentration on the condensation of furfural withN‐vinylcarbazole and its polymer was studied. The polymers were chemically modified into phosphonic acid cation exchange resins. The effects of variation of AlCl3, PCl3, and furfural amounts, reaction time, and rephosphorylation on the synthesis and capacities of cation exchange resins were also st

ISSN:0021-8995    

DOI:10.1002/app.1982.070270117

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

年代:1982

数据来源: WILEY

摘要:

AbstractThermal stabilities of the crosslinkedN‐vinylcarbazole/poly(N‐vinylcarbazole)‐furfural polymers and of the phosphonic acid resins prepared thereform were studied by thermogravimetric analysis. The overall thermal stability of the crosslinked polymers is greater than the same for poly(N‐vinylcarbazole) and is further improved upon phosphorylation. The resins are stable in 5Nacids and water at 100°C. Isothermal oxidative degradation studies of the resins indicate significant increase in the capacities. pH metric titration of the resins shows the presence of mono and dibasic phosphonic acid groups. The resins realize about 90% of their capacities within 2 min of equil

ISSN:0021-8995    

DOI:10.1002/app.1982.070270118

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

年代:1982

数据来源: WILEY

摘要:

AbstractIsobutylene tetramers (IB4) were obtained in high yield by the cationic dimerization of commercial diisobutylene (DIB) (2,4,4‐trimethyl‐1‐pentene with isomeric impurities) with CF3SO3O3H or CH3COClO4as catalyst. The best IB4yields (80–90%) were achieved at 0–30°C in nonpolar solvents (n‐hexane and CCl4). The major components in the IB4produced under these conditions were 2,2,6,6,8,8‐hexamethyl‐4‐methylenenonane (8) and 2,2,4,6,6,8,8‐heptamethyl‐4‐nonene (9) that arose via simple linear dimerization of DIB. The yield of IB4was almost independent of the monomer concentration ranging from 10 to 50 vol % at 0°C, but decreased at higher temperatures (>50°C) or in a polar solvent [(CH2Cl)2] because of the formation of higher oligomers and side reactions such as cracking. A Lewis acid catalyst (AlEtCl2) resulted in a very complex mixture of C12–C20hydrocarbons at 0°C in CCl4; the yield of IB4was less than 40%. The catalytic difference between oxo acids a

ISSN:0021-8995    

DOI:10.1002/app.1982.070270119

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

年代:1982

数据来源: WILEY

摘要:

AbstractIt was confirmed that one of the principal factors which influences the acoustical absorption of flexible polyurethane foam is flow resistance of foam. Normal polyester‐based flexible polyurethane foam itself has an adequate value of flow resistance and shows fairly good sound absorption. Acoustical absorption of normal polyether‐based flexible polyurethane foam, which generally has lower flow resistance, can be improved by using some expedients such as setting up a certain skin layer on the foam surface so that the flow resistance of the foam can be increased. Surface treatment of foam such as gluing film, heat melting, spraying, or heat adhesion with film can not only improve sound absorption and mechanical properties of polyether‐based flexible polyurethane foam, but also improve the hydrolysis resistance of polyester‐based flexible polyurethane foam. Inserting some metal foil or plastic film between flexible polyurethane foams can change the sound absorption behavior according to the position of the foil or the film in the foam. The effects of foam thickness, existence of air layer behind foam, and foam profiling on acoustic absorption were also inves

ISSN:0021-8995    

DOI:10.1002/app.1982.070270120

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

年代:1982

数据来源: WILEY