An appraisal of rheological models as applied to polymer melt flow

Han, C. D.; Kim, K. U.; Siskovic, N.; Huang, Ching‐Rong

doi:10.1007/bf01525305

Cited by 28 publications

(20 citation statements)

References 36 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…It will induce the morphological heterogeneity; hence the structural irregularities on the lamella-sheets of the EOR domains. In addition, the principal normal stress, making the EOR domains orient along the TD, tend to be much stronger than the shear stress operating along the FD upon injection-molding, which would generate more short-fibrils and/or coarse fibrils frequently observed in the TD as a result of the completion of the fibril-to-droplet transition 24,25) . Figure 6 shows the CLTE profiles on (a) FD, (b) TD, and (c) ND as a function of temperature.…”

Section: Temt Observationmentioning

confidence: 99%

Study on Three-dimensional Structures in Injection-molded iPP/Poly(ethylene-co-octene) by Transmission Electron Microtomography

et al. 2006

View full text Add to dashboard Cite

One of the conventional solutions for such issue is adding inorganic fillers (talc, glass fiber and mica) with high aspect ratios, and suppressing the volume expansion by simple mechanical restraints [4][5][6] . However, such filler-PP composites have caused poor appearance and weight increase in molded articles fabricated using them. Recently, new techniques were proposed to reduce the CLTE of the injection-molded iPP-based parts in which thermoplastic elastomers (TPE) having well-controlled structures are used as an additive instead of fillers to tune the CLTE [7][8][9][10] . In these papers, the elastomers inclusions were highly deformed both along the FD and transverseto-flow (TD) directions and co-continuously dispersed with the iPP. Abstract A phase-separated structure of the injection-molded isotactic polypropylene (iPP)/poly(ethylene-co-octene) (EOR) binary blend was studied in three-dimension (3D) by transmission electron microtomography (TEMT). Highly oriented EOR domains along both flow-(FD) and transverse-to-flow (TD) directions resulting in stacking lamella-sheet like structures to normal direction (ND) were confirmed. Some irregularities in morphology and intervals between the EOR sheets, and thickness heterogeneity of the sheets, were observed more frequently in the TD rather than in the FD. Using the 3D information obtained by the TEMT, we have tried to elucidate massive anisotropy in linear thermal expansion coefficient (CLTE) along the injection directions in this blend. We found that the CLTE anisotropy was well correlated with the lamella-like sheets arrays and their irregularities.

show abstract

Section: Temt Observationmentioning

confidence: 99%

Study on Three-dimensional Structures in Injection-molded iPP/Poly(ethylene-co-octene) by Transmission Electron Microtomography

et al. 2006

View full text Add to dashboard Cite

show abstract

“…For illustration, here I consider one such study. Figure 12 describes the effect of blend composition on the bulk viscosity g of HDPE/PS blends at 200 C for different values of shear stress r [27]. It should be mentioned that the values of g given in Fig.…”

Section: Critique Of Experimental Methods Used For Determining the Melmentioning

confidence: 99%

“…1-4, we already have shown that the bulk rheological behavior of an immiscible polymer blend is intimately related to its morphology. Figure 13 gives micrographs of the extrudates of three HDPE/PS blends, in which the dark areas represent the PS phase which was etched using toluene and the bright areas represent the HDPE phase [27]. Notice in Fig.…”

Section: Critique Of Experimental Methods Used For Determining the Melmentioning

confidence: 99%

See 1 more Smart Citation

Untitled

2009

Polymer Engineering & Sci

View full text Add to dashboard Cite

The purpose of this article is to clear the confusion in the literature on the following two issues: (1) determination of the bulk viscosity of immiscible polymer blends using a plunger-type capillary viscometer and (2) modeling the composition dependence of the bulk viscosity of immiscible polymer blends. Related to the first issue, it is pointed out that measurement of the total pressure drop across the entire length of a capillary die, while using a plunger-type viscometer, to determine the bulk viscosity of an immiscible polymer blend is not justified. This is because the morphology (the state of dispersion) of an immiscible polymer blend varies along the axis of a capillary die. Related to the second issue, it is pointed out that the use of such empirical expressions as inverse additivity or logarithmic additivity relationships is of no rheological significance to determine the composition dependence of the bulk viscosity of immiscible polymer blends. This is because such empirical expressions do not contain terms describing the state of dispersion of an immiscible polymer blend. A computational approach is suggested, though formidable but not insurmountable, which will lead to establishing rheology-morphology-processing relationships in immiscible polymer blends.

show abstract

“…It is not unexpected that the moduli of the individual master batches can be varied by adjusting the amount of carbon black. The order of the moduli ratio of the master batch pairs which were cross-mixed to form the blend compounds is as follows: (1) In later sections we will discuss how this moduli ratio of the master batch pairs Table IV lists the moduli of the cross-mixed blend compounds having different amounts of carbon black in the master batches. It is noted that there are slight differences in the moduli.…”

mentioning

confidence: 99%

Experimental studies of the relationship of processing to the crack growth of carbon‐black‐loaded SBR—cis‐polybutadiene compounds

Lee¹

1982

J of Applied Polymer Sci

View full text Add to dashboard Cite

SynopsisThe crack growth of a highly carbon-black-loaded SBR-cis-polybutadiene (BR) blend is investigated as a function of the distribution of carbon black in the individual rubber phases. The blend compound consists of SBR/BR/carbon blackloil = 60140/85160 by weight ratio and curatives. A new "old process" is devised to control the carbon black distribution in the individual rubber phases, that is, cross mixing the SBR and BR black master batches with different amounts of carbon black in the SBR and BR patchea The results show that crack growth is very sensitive to the carbon black distribution. A better crack growth resistance compound is seen containing proportionately more carbon black in the major rubber SBR phase. A simple analogy of rubber blends to the rubbermodified thermoplastics is proposed to interpret these findings. The heat buildup of the blends is also a f f d by the carbon black distribution. A low heat buildup compound is observed in the system in which more carbon black is in the SBR batch, which is aLS0 a better crack growth resistance compound. Itisnotumxpe@d ' that the strength of rubbers decreaeee with increase of temperature, and so the rate of crack growth becomes faster as heat builds up.

show abstract

An appraisal of rheological models as applied to polymer melt flow

Cited by 28 publications

References 36 publications

Study on Three-dimensional Structures in Injection-molded iPP/Poly(ethylene-co-octene) by Transmission Electron Microtomography

Study on Three-dimensional Structures in Injection-molded iPP/Poly(ethylene-co-octene) by Transmission Electron Microtomography

Untitled

Experimental studies of the relationship of processing to the crack growth of carbon‐black‐loaded SBR—cis‐polybutadiene compounds

Contact Info

Product

Resources

About