摘要:

A study on the flow behavior of blends of natural rubber (NR) and epoxidized natural rubber (ENR) latices was carried out using a Contraves viscometer. The effects of blend ratio, shear rate, and temperature on the flow properties were determined. The viscosities of the blends showed negative deviation from additivity. Unlike the homopolymer latices, the viscosities of the blends increased with increase of temperature. Blends are found to be less pseudoplastic than homopolymers.

ISSN:0360-2559    

DOI:10.1080/03602559608000077

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

The electronic absorption spectra of thin films of pure poly(methyl methacrylate) (PMMA) and PMMA doped with acceptors, donors, and acceptor-donor systems were recorded in the range 200–900 nm. The acceptors are tetracyanoquinodimethane (TCNQ), tetracyanoethylene (TCNE), and chloranil (Chl). The donors consist of two groups. The first group is anthracene (An), rhodamine 6G (Rh 6G), rhodamine B (Rh B), and naphthalene 1,3 diol (Nph). The second group is the substituted phenyl hydrazone (H, CH3, OCH3, and O,P dichloro). Both donors and acceptors absorb with low to medium intensity in the ultraviolet and visible regions from 250 to 600 nm. The electrical resistivity of the sensitive systems was measured and the activation energy was determined.

ISSN:0360-2559    

DOI:10.1080/03602559608000078

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

The melt fracture and morphology of HOPE blends (HDPE/EPDM and HDPE/zinc-neutralized sulfonated EPDM, Zn-SEPDM, plasticized with different plasticizers) were studied through a capillary rheometer and scanning electron microscopy (SEM). The results show that the addition of a small amount of GR (modified glyptal resin) to Zn-SEPDM reduces the melt elasticity and the tendency of extrudate distortion of HDPE/Zn-SEPDM/GR blend considerably as compared to HDPE/EPDM and HDPE/Zn-SEPDM/Zn-St blends, resulting in improvement of processability of the blend.

ISSN:0360-2559    

DOI:10.1080/03602559608000079

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

Copolymerization of styrene and divinylbenzene has been carried out in suspension, in the presence of poly(vinyl acetate) of three molecular weights (41,306, 118,600, and 216,000), in order to prepare macroreticular copolymers which possess large and very large pore sizes. The copolymer beads have specific surface areas less than 10.0 m2/g and average pore radii of 75,000 nm. By means of scanning electron microscopy and Hg-porosimetry, the bead structure was proved to be porous, being formed from the agglomerations of microparticles with large void volumes. According to the Hg-porosimetry analyses, the pore size distributions depend on the synthesis parameters.

ISSN:0360-2559    

DOI:10.1080/03602559608000080

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

Ten different formulations were developed using urethane triacrylate oligomer with a monofunctional monomer and a difunctional monomer in the presence of a number of additives. Films were cured under U V radiation and their properties were characterized. Hessian cloths (jute product) were coated with these formulations and cured under UV radiation. Enhancement of tensile strength(200%) and elongation (40–60%) with reduced water uptake of the treated Hessian cloth is reported.

ISSN:0360-2559    

DOI:10.1080/03602559608000081

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

Crystallization properties of polypropylene (PP) in PP/Ag composites were estimated from differential scanning calorimetry (DSC) and wide-angle x-ray diffraction studies. The effect of Ag powder and its surface modification with a titanate coupling agent on rates of nucleation and growth of crystallization, crystallite size distribution, and crystallinity was determined from crystallization exotherm peaks. Crystallinity and tensile properties such as modulus, yield strength, and breaking elongation decreased with Ag concentration. Linear correlations were obtained with tensile and crystallization parameters in both types of composites.

ISSN:0360-2559    

DOI:10.1080/03602559608000082

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

The properties of acrylonitrile-butadiene rubber (NBR)/poly(vinyl chloride) (PVC) blend based microcellular (MC) sheets were studied. A comparative evaluation of suspension-grade and emulsion-grade PVC based MC soles was done. The study stressed the optimum percentage precure, the blend ratio, amount of plasticizer, and the concentration of blowing agent required for obtaining optimum physical properties of NBR/PVC blends. It was found that NBR/suspension PVC blend based MC sheet shows better abrasion resistance, split tear strength, and hardness, and low water absorption. NBR/emulsion PVC blend based MC sheet shows higher expansion, extralight weight, and lower density. Replacement of a part of DOP by amine-terminated liquid natural rubber (ATNR) increases the cure rate and improves split tear strength, hardness, etc.

ISSN:0360-2559    

DOI:10.1080/03602559608000083

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

Molecular transport of haloalkanes into polymeric blend sheets of ethylene-propylene random copolymer and isotactic polypropylene, Santoprene, has been investigated gravimetrically in the temperature interval 25°-70°C. Equilibrium sorption, desorption, resorption, redesorption, and degree of penetrant overshoot were influenced by the type of haloalkane used and the experimental temperature. Diffusion coefficients have been computed for the sorption (S), desorption (D), resorption (RS), and redesorption (RD) runs. Temperature-dependent sorption and diffusion coefficients were analyzed using the Arrhenius relation. Santo-prene-haloalkane interactions have been discussed in terms of sorption, desorption, and diffusion coefficients.

ISSN:0360-2559    

DOI:10.1080/03602559608000084

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

Composites based on styrenated methacrylate vinyl ester, quartz, and fused alumina were prepared in a lab model Sigma blender and polymerized at room temperature by catalysis. Lead ore galena was grafted in between as two layers, wetted with the monomer, and compression molded. After complete curing the specimen was cut with a slow-speed diamond cutter and observed at the interfaces for morphology. SEM studies revealed excellent compatibility and some compounding at the interphases.

ISSN:0360-2559    

DOI:10.1080/03602559608000085

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

Multiple injection cavities are automatically balanced by adjusting runner and gate sizes based on an iterative redesign methodology integrated with computer-aided engineering (CAE) packing simulation. For runner balancing, each cavity must be filled simultaneously at uniform pressure. In addition, the time-pressure history of the polymer melt over the entire molding cycle should be considered. Based on the proposed methodology, a multicavity mold with identical cavities is balanced to minimize entrance pressure differences among various cavities at discrete time steps of the molding cycle. The results have shown more than a 95% reduction of the entrance pressure differences over other related studies, and also have demonstrated increased searching performance over other optimization techniques. A family mold with different cavity volumes and geometries is also balanced to minimize pressure differences at the end of the melt flow path in each cavity on a basis of discrete time steps of the molding cycle. The methodology has shown uniform pressure distributions among the cavities during the entire molding cycle.

ISSN:0360-2559    

DOI:10.1080/03602559608000086

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor