摘要:

AbstractPoly(lactam thioether) was synthesized from tetrahydro‐1,4‐thiazepine‐5(4H)‐one by a ring opening reaction under various conditions and was evaluated as positive electron beam(EB) resist. It was found that poly(lactam thioether) was easily decomposed by EB irradiation. The decomposition by EB exposure may be attributed to cleavage of CS bonds in the polymer chains. The sensitivity of poly(lactam thioether) was influenced by prebake temperature, molecular weight, and developer, a high sensitivity of 5.3 × 10−6coulomb/cm2was observed with a good resolution of less than 1 μm. Poly(lactam thioether) showed a high sensitivity and a high resolution, and is suitable as a posit

ISSN:0032-3888    

DOI:10.1002/pen.760261002

出版商:Society of Plastics Engineers    

年代:1986

数据来源: WILEY

摘要:

AbstractStudies of the physical and mechanical properties of melt crystallized ultra‐high molecular weight polyethylene morphologies from melts with different thermal histories indicate that their properties depend on the degree of fusion of the powder particles during their processing and can be enhanced by heating the polymer above 220°C. The degree of cohesion of the powder particles and their initial morphology also have a significant effect on the deformability of the polymer in the solid state forming methods used to prepare high modulus and strength produc

ISSN:0032-3888    

DOI:10.1002/pen.760261003

出版商:Society of Plastics Engineers    

年代:1986

数据来源: WILEY

摘要:

AbstractThe rheological behavior of sulfonated polyisobutylene based elastomeric ionomers has been studied. The effects of molecular architecture, type of cation, and addition of excess neutralization agent were investigated. The effect of temperature was studied to a limited extent. In a specific case, the influence of an ionic plasticizer, zinc stearate was also examined. It was found that in these telechelic ionomers where the ionic groups are located exclusively at the chain ends, significant Ionic interactions may persist even at 180°C. The zinc‐neutralized ionomers had the lowest viscosity as compared to the corresponding potassium‐ or calcium‐neutralized ionomers. The covalent character of zinc is believed responsible for this behavior. Other factors being constant, the triarm based ionomers are more viscous than the monofunctional ionomers. A mixture of monofunctional ionomers with the triarm, species is a model for dangling chain ends, and results in a slight lowering of the viscosity under the conditions studied. Zinc stearate acts as an ionic plasticizer. Upon the addition of 15 percent by weight of zinc‐stearate to the ionomer, the low shear rate viscosity drops by several orders of magnitude and renders the ionomer thermally processable at moderate temp

ISSN:0032-3888    

DOI:10.1002/pen.760261004

出版商:Society of Plastics Engineers    

年代:1986

数据来源: WILEY

摘要:

AbstractAn experimental investigation was conducted into elucidating the mechanism of foam devolatilization. For the investigation, we have constructed two separate apparatuses of Plexiglas—one simulating the partially filled flow channel in a single‐screw devolatilizer, and the other simulating the partially filled, closed‐chamber (often referred to as the “C‐chamber),” in a twin‐screw devolatilizer. The test fluids employed were aqueous solutions of polyacrylamide having various concentrations. During the preparation of the test fluids, we controlled the amount of air entrapped in the liquid phase by varying the level of vacuum applied. The entrapped air stayed as fine gas bubbles dispersed in the polymer solution, and mixtures of the polymer solution and air bubbles were subjected to devolatilization experiments. In the use of a single‐screw devolatilizer, we have observed that: 1. The streamlines show circulatory flow patterns forming a singular point at a position slightly below the free surface, where small gas bubbles are trapped initially and become stationary, and 2. The small gas bubbles trapped at the stationary position coalesce later to form large gas bubbles, which then move slowly toward the free surface and are removed under vacuum from the system. In the use of twin‐screw devolatilizers, we have found that the degree of fill, the rotational direction of the screws, and the degree of intermeshing, (i. e., partially or fully intermeshing) greatly influence the amount of free surface available for the removal of volatiles, as well as the flow patterns in the liquid pool, and thus the devolatili

ISSN:0032-3888    

DOI:10.1002/pen.760261005

出版商:Society of Plastics Engineers    

年代:1986

数据来源: WILEY

摘要:

AbstractA theoretical study of the one‐directional coextrusion flow of two molten polymers between parallel plates has been carried out using a non‐isothermal power‐law model. A numerical method has been used to solve simultaneously the momentum and energy balance equations, in order to obtain the evolutions of the interface position, the pressure gradient, and the temperature profiles all along the flow. The theoretical results are in good agreement with experimental values measured on an industrial coextrusion

ISSN:0032-3888    

DOI:10.1002/pen.760261006

出版商:Society of Plastics Engineers    

年代:1986

数据来源: WILEY

摘要:

AbstractDrawing of a semicrystalline polymer causes a molecular transformation from a spherulitic‐to‐fibrillar morphology. Shrinkage, which is a characteristic property of polymeric fibers, reverses, to a large extent, the extension that takes place during the deformational process of drawing. This paper focuses on the shrinkage behavior of various drawn semicrystalline polymers and the results are used as further evidence for the feasibility of a phase‐transition model whose mechanism can be generally termed “strain‐induced recrystal

ISSN:0032-3888    

DOI:10.1002/pen.760261007

出版商:Society of Plastics Engineers    

年代:1986

数据来源: WILEY

摘要:

AbstractThe National Center for Small‐Angle Scattering Research (NCSASR) is a user dedicated national facility at the Oak Ridge National Laboratory. It is sponsored by the National Science Foundation under an interagency agreement with the Department of Energy. The facilities of the Center include the NSF funded. 30‐m small‐angle neutron scattering (SANS) instrument at the High Flux Isotope Reactor, as well as part‐time use of four other small‐angle x‐ray and SANS instruments. One of the most active areas of SANS research has been polymer science and over half the proposals received by the Center have been in this area. Approximately 20 percent of the beam time has been allocated to users in the chemical industry for the study of polymer structure, and this paper reviews some highlights of this work in the areas of chain configuration in bulk polymers and solutions, the structure of blends and networks and investigations of core‐shell latexes. In addition some of the first time‐dependent experiments performed on the 30‐m facil

ISSN:0032-3888    

DOI:10.1002/pen.760261008

出版商:Society of Plastics Engineers    

年代:1986

数据来源: WILEY

摘要:

AbstractFlexural properties of moldings made by Reaction Injection Molding (RIM), which are structural foams consisting of high density skin and low density core, were investigated by three‐point bending tests. Two failure modes were observed in bending tests of the moldings made by RIM, and they are classified as follows according to the density ratio of skin layer to core layer: the opposite side of the skin layer to which load was subjected failed by tensile stress: and the same side of the skin layer to which load was subjected failed by compressive stress, causing wrinkling or buckling. Then the conventional composite beam theory was applied to the former failure mode and Hoff s buckling theory to the latter, and equations were derived to predict the flexural properties of the structural foams, which involved buckling from the flexural properties of solid construction. In addition, it has been shown that there exists a density distribution that maximizes the flexural strength of the moldings made by RIM with a given overall density. The results obtained here should be useful to the optimum structural design of moldings made by RI

ISSN:0032-3888    

DOI:10.1002/pen.760261009

出版商:Society of Plastics Engineers    

年代:1986

数据来源: WILEY

摘要:

AbstractIt has been confirmed that the reaction model proposed previously, which can express simultaneously the oligomer properties and the distillate properties under low esterification pressure, is applicable to a continuous direct esterification process in a practical plant. The experimental data of the first esterification reactor (RA‐1) was obtained under low reaction pressures (atomospheric or 1 kg/cm2G) with the pilot plant throughput based on poly(ethylene terephthalate) (PET) polymer production of about 50 kg/h. The Arrhenius' parameters, frequency factor, and apparent activation energy, were determined fitting the experimental data of the pilot plant by using the Simplex method as an optimization technique. The activation energy of diethylene glycol (DEG) formation,E7, is about twice as much as those of the esterifications,E1,E2,E3, andE4. The activation energies areE1, = 19640 cal/mol,E2= 18140,E3= 22310,E4= 18380,E5= 2810,E6= 14960, andE7= 42520 cal/mol. Good agreement was obtained between experimental data and calculated predictions for several oligomer and distillate properties. The vapor‐liquid equilibrium can be expressed by Raoult's law with little problem of practical

ISSN:0032-3888    

DOI:10.1002/pen.760261010

出版商:Society of Plastics Engineers    

年代:1986

数据来源: WILEY

ISSN:0032-3888    

DOI:10.1002/pen.760261001

出版商:Society of Plastics Engineers    

年代:1986

数据来源: WILEY