Upgrading the melt flow index to rheogram approach in the low shear rate region

Shenoy, Aroon; Saini, D. R.

doi:10.1002/app.1984.070290513

Cited by 4 publications

(3 citation statements)

References 13 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Since the MFI provides an indirect assessment of the molecular weight based on the flowability at relatively low shear rates [ 66 , 67 , 68 ], the relative melt flow index was computed as the ratio between the MFI of the virgin and recycled nanocomposite. After three reprocessing cycles, no significant changes were observed in the relative MFI of the recycled nanocomposites with 1 wt.% and 5 wt.%.…”

Section: Resultsmentioning

confidence: 99%

Mechanical Recycling of Ethylene-Vinyl Acetate/Carbon Nanotube Nanocomposites: Processing, Thermal, Rheological, Mechanical and Electrical Behavior

2023

View full text Add to dashboard Cite

Recycling polymer/carbon nanotube (CNT) nanocomposites is not well common, despite a growing interest in using polymer/carbon nanotube (CNT) nanocomposites in industrial applications. In this study, the influence of mechanical recycling on the thermal, rheological, mechanical and electrical behavior of ethylene-vinyl acetate (EVA)/CNT nanocomposites is investigated. EVA/CNT nanocomposite with different amounts of CNTs (1, 3 and 5 wt.%) was subjected to mechanical grinding and reprocessing by injection molding in a close-loop up to three cycles, and the changes induced by mechanical recycling were monitored by Differential Scanning Calorimetry (DSC), capillary rheology, scanning electron microscopy (SEM), electrical resistance and tensile tests. It was found that the EVA/CNT nanocomposites did not exhibit significant changes in thermal and flow behavior due to mechanical recycling and reprocessing. The recycled EVA/CNT nanocomposites retain close to 75% of the original elastic modulus after three recycling cycles and about 80-90% in the tensile strength, depending on the CNT loading. The electrical conductivity of the recycled nanocomposites was about one order of magnitude lower as compared with the virgin nanocomposites, spanning the insulating to semi-conducting range (10−9 S/m–10−2 S/m) depending on the CNT loading. With proper control of the injection molding temperature and CNT loading, a balance between the mechanical and electrical properties of the recycled EVA nanocomposites can be reached, showing a potential to be used in practical applications.

show abstract

Section: Resultsmentioning

confidence: 99%

Mechanical Recycling of Ethylene-Vinyl Acetate/Carbon Nanotube Nanocomposites: Processing, Thermal, Rheological, Mechanical and Electrical Behavior

2023

View full text Add to dashboard Cite

show abstract

“…Melt flow data are used for quality control, although most agree that the shear rate is too low to represent extrusion and only partially it can represent molding operations. Also, MFI is insensitive to molecular weight distribution effects in the low shear rate region 13, 16, 17. The equipment used in the polymer industry requires a heated barrel (due to the melting and flow properties of these materials), where the sample is allowed to flow under a specified weight placed on top of the cylindrical barrel.…”

Section: Flow Indexmentioning

confidence: 99%

Simple method to determine flow characteristics of injectable hydrogels

Nadarajan

Nguyen

Kolb

et al. 2010

J of Applied Polymer Sci

View full text Add to dashboard Cite

This article presents a simple inexpensive method to measure flow and viscoelastic properties of calcium alginate hydrogels or gel solutions and is particularly suitable for quality control in small laboratory settings. This method can be considered an extension of the Melt Flow Index (MFI) method, which is routinely used in the polymer industry to indirectly determine the molecular weight of polymers. Results of alginate gels at various crosslinking densities obtained with this new test are compared to complex viscosity data obtained from a standard cone and plate rheometer, and demonstrate very good correlation. A mathematical model describing the apparent viscosity of the alginate gels in this test has also been developed.

show abstract

“…= f l f 2 (Z)" (55) where f , is the function of the geometric parameters based on the shape of the die, f2 is a function of the fluid properties, namely, K and n as given by Eq. (26), Ld is the length of the die, and H, is a characteristic geometric parameter specific to each geometric shape.…”

Section: Aphjmfi)" 2ldmentioning

confidence: 99%