摘要:

AbstractSorption characteristics of vapors of pure hydrocarbon and their binary mixtures in low‐density polyethylene were studied under various conditions of temperature and pressure. A new apparatus devised and utilized for the determination of composition of sorbed vapor in case of binary mixtures is described. The study demonstrates the effect of the presence of one component within the polymer on the sorption of another and also the occurrence of selectivity in sorptio

ISSN:0021-8995    

DOI:10.1002/app.1982.070270201

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

年代:1982

数据来源: WILEY

摘要:

AbstractThe yield and quality of an electrophoretically deposited polyimide are strongly dependent upon a number of parameters that are closely related to the formulation and characteristics of a basic nonaqueous electrophoretic emulsion. Such parameters, which have been optimized for one specific polyimide, are solvent/precipitant ratio, type and concentration of surfactant, emulsion preparation sequence, apparent pH, and solids content.

ISSN:0021-8995    

DOI:10.1002/app.1982.070270202

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

年代:1982

数据来源: WILEY

摘要:

AbstractPrevious articles from this laboratory have described a model for predicting the second virial coefficient of a polymer solution given the polymer molecular weight and its intrinsic viscosity in the particular solvent. The same theory is used in this report to calculate values of the Flory–Huggins interaction parameter χ. The method is different in that χ is obtained through manipulation of simulated exprimental data in exactly the same way as in an actual experiment. Agreement between estimated χ values and those obtained at infinite dilutions from membrane osmometry or light scattering is within 2%, on the average. The model accounts for the molecular weight dependence

ISSN:0021-8995    

DOI:10.1002/app.1982.070270203

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

年代:1982

数据来源: WILEY

摘要:

AbstractThe evolution of the latex particle diameter distribution during batch emulsion polymerization is investigated, with emphasis on changes in the breadth of the size distribution. A model utilizing a surface area‐dependent volumetric growth rate of a single particle results in a time‐invariant standard deviation of the size distribution during periods of particle growth only. This behavior is reconciled with some experimental observations by considering the occurrence of particle nucleation during some part of the growth interval. Conclusions based on the results of the model suggest that higher inhibitor and low emulsifier concentrations favor narrow particle size distributi

ISSN:0021-8995    

DOI:10.1002/app.1982.070270204

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

年代:1982

数据来源: WILEY

摘要:

AbstractVarious poly(1‐olefin)s have been studied as homoelectrets and their stabilities under different environmental conditions have been determined. It has been found that the stabilities of the homoelectrets, prepared from these polymers, depend on their volume resistivities, degrees of crystallinity, and the temperatures at which the crystalline domains of these polymers undergo transitional motions. Excellent stabilities have been exhibited by the homoelectrets prepared from poly(3‐methyl‐1‐butene), poly(4‐methyl‐1‐pentene) and other similar isotactic poly(1‐olefin)s with pendant branched side chains. It is postulated that the charged particles are trapped at the crystalline/amorphous interfaces in these polymers and the bulky alkyl substituents stabilize the charged particles by raising the transition temperatures of these polymers as well as by providing some additional chemical in

ISSN:0021-8995    

DOI:10.1002/app.1982.070270205

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

年代:1982

数据来源: WILEY

摘要:

AbstractViscoelastic fluids were injected into a high velocity airstream (200 m/s) to investigate how the addition of small polymer quantities to fluids significantly increase the resultant disseminated drop size. For each liquid tested several hundred resultant drops were sampled and measured using an automated image analyzer. The resultant mass median diameter (MMD) for a viscoelastic fluid was an order of magnitude larger than a comparable viscous Newtonian fluid. A relaxation time measured from a die swell experiment correlates the dissemination results suggesting, an elongational rather than shear breakup mechanism.

ISSN:0021-8995    

DOI:10.1002/app.1982.070270206

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

年代:1982

数据来源: WILEY

摘要:

AbstractTorsional impregnated cloth analysis (TICA) temperature scan results of an acetylene‐terminated quinoxaline system indicated the presence of two different reactions with different activation energies. Two additional effects are delineated when cure is carried out in the presence of air. Curing at low temperature in the presence of air will lower the finalTg, but at high temperature it will have the opposing effect. The two reactions that can occur under nitrogen are affected differently by air curing. It appears that one is prohibited by the lower temperature curing in air while the other is no

ISSN:0021-8995    

DOI:10.1002/app.1982.070270207

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

年代:1982

数据来源: WILEY

摘要:

AbstractEpoxy‐modified polyolefins have been prepared by the radical grafting of glycidyl methacrylate to polymer melts. The reactions of these materials with amines and carboxylic acids were investigated. The modified polymers undergo typical epoxide reaction

ISSN:0021-8995    

DOI:10.1002/app.1982.070270208

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

年代:1982

数据来源: WILEY

摘要:

AbstractThe dielectric constant ϵ′ and the loss factor ϵ″ of moistened wood were measured over a wide range of moisture content (MC), 0–40 wt% in the temperature range −196 to 0°C, and in the frequency range 30 Hz to 1 M Hz. Three relaxations were observed depending on the MC and frequency. The first ϵ″ peak at −103°C (30 Hz) in oven‐dried wood is known to be due to the methylol rotation in the amorphous regions. A new ϵ″ peak (second peak), which appeared for MC>0.6 wt% at −110 to −40°C (30Hz) depending on the MC, is assigned to the local mode motions of the complexes between moisture and polar groups in the wood system; it is enhanced as the overall loosening of the initial hydrogen bond network is promoted by the extended hydration due to further sorption of moisture. The peak temperatures and the activation energies for these relaxations changed complexly depending on the MC. At MC>10 wt%, a novel ϵ″ peak (third peak) was disclosed around −40°C (30 Hz) as a shoulder of the ionic conduction. This novel peak may be attributed to the water frozen in wood on the basis of the peak temperature, relaxation strength vs. MC, the activation energy, and the fact that the peak is not observed for the sorption of various polar organic solvents. This suggests that some of the moisture sorbed by wood may probably exist in a frozen state at low temperatures, even at a MC well below the commonly

ISSN:0021-8995    

DOI:10.1002/app.1982.070270209

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

年代:1982

数据来源: WILEY

摘要:

AbstractTemperature dependences of viscoelastic characteristics for a model system epoxy resin–glass beads covered with poly(buthylmethacrylate) were studied. The formation of interphase region was established with its own relaxation maximum. The structure of this region is supposed to be a kind of semi‐interpenetrating network formed by crosslinked and linear polymers. Using the Gordon–Taylor equation, the volume fractions of both polymeric components in the interphase region were calculated. An experimental evidence in favor of theoretical calculations has been obtained showing some increase in the glass transition temperature of a two‐phase polymeric system by introducing small amounts of the component with a lower glass temperature as compared with this temperature for the main co

ISSN:0021-8995    

DOI:10.1002/app.1982.070270210

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

年代:1982

数据来源: WILEY