SPE Library
The SPE Library contains thousands of papers, presentations, journal briefs and recorded webinars from the best minds in the Plastics Industry. Spanning almost two decades, this collection of published research and development work in polymer science and plastics technology is a wealth of knowledge and information for anyone involved in plastics.
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Rheology
Dispersion in nanocomposites
Frank Yepez-Castillo, Brian Grady, June 2012
Re-agglomeration of carbon nanotube fillers does not affect a polymer's mechanical properties.
Determining drug solubility in polymer by rheological methods
John Suwardie, May 2012
Using flow characterization techniques to assess drug solubility in polymer is faster and more accurate than thermal or microscopic approaches.
Capillary flow of low-density polyethylene
Savvas G. Hatzikiriakos, Mahmoud Ansari, Thanasis Zisis, Evan Mitsoulis, May 2012
Low-density polyethylene melts in capillary flow show large vortices and high-pressure drops due to the highly viscoelastic nature of the melt and the pressure dependence of the viscosity.
Improved properties of hybrid epoxy nanocomposites
Hatem Alamri, It-Meng (Jim) Low, May 2012
Using both halloysite and recycled cellulose fibers as fillers in epoxy composites enhances their thermal stability, mechanical, and fracture properties.
THE CHARACTERISTICS OF IMMISCIBLE POLYMER BLENDS WITH MWNT
Sang Min Kim, Tae Yong Hwang, Jae Wook Lee, May 2012
The electrical, rheological properties and phase behavior of multiwalled carbon nanotube (MWNT) filled with Polypropylene(PP)/Polystyrene(PS) blends were investigated. Based on the matrix polymer, two kinds of masterbatch chips were used to prepare ternary blends, and the influence of the kinds of masterbatch were confirmed on the phase morphology of ternary blends and the distribution of MWNT in ternary blends.
ENHANCEMENT OF MELT ELASTICITY OF LONG-CHAIN BRANCHED POLYETHYLENE BY BLENDING A LINEAR POLYETHYLENE
Masayuki Yamaguchi, Naoya Mieda, May 2012
The rheological properties are studied for binary blends composed of a long-chain branched polyethylene and a linear polyethylene. It is found that the blends containing a linear polyethylene with high shear viscosity exhibit enhanced elasticity in the molten state, which is attributed to the prolonged relaxation time for entanglement couplings between a linear polymer and a branched polymer.
RHEOLOGICAL AND MECHANICAL PROPERTIES OF POLYMER BLENDS, RADIOPAQUE FILLERS AND COUPLING AGENT
Breanna G. Boyden, Brian C. LaBrec, Vijay Wani, May 2012
This work studied the effect of blending two different grades of thermoplastic polyurethanes with a constant percentage of radiopaque filler (bismuth subcarbonate) and varying percentages of filler. A titanate binding agent was added to the blend to investigate the impact of improved polymer/filler adhesion. The results showed that varying grades of thermoplastic polyurethane in conjunction with different filler loadings can modulate the physical properties of the compound.
FOLLOWING CHEMICAL REACTIONS WITH RHEOMETRY AND SIMULTANEOUS FTIR-SPECTROSCOPY
Fabian Meyer, Jan Philip Plog, Manfred Feustel, May 2012
A new combination of a rheometer and a FTIR-spectrometer will be presented. The Rheonaut module allows the coupling of the Thermo Scientific HAAKE MARS rheometer with an FTIR-spectrometer. With this set-up, samples can be characterized rheologically while IR-spectra are being recorded simultaneously. To test this concept, polymerization reactions have been followed with the combination of the HAAKE MARS and the Rheonaut module. Details of the instrument set-up as well as selected results will be presented.
PRACTICAL USE OF CREEP TEST TO OBTAIN THE RHEOLOGICAL DATA AT LOW FREQUENCY RANGE FOR POLYETHYLENE
Yongwoo Inn, David C. Rohlfing, May 2012
The creep test was applied to obtain rheological information in low-frequency range that is not reachable by use of the frequency sweep test for polyethylene industrial research and development. The test time scale and the applying stress were considered to make the measurement on a large group of samples. By testing several high molecular weight resins having broad molecular weight distribution or long chain branching, we demonstrated utility of this methodology.
SWELLING OF PLA MELT DUE TO CO2 DISSOLUTION
Syed Mahmood, Chul Park, May 2012
The superior mechanical properties of microcellular foams such as, heat resistance, lightweight and high performance to weigh ratio, are important factors to be considered with respect to the automotive industry and foaming industries. Therefore, an understanding of the thermophysical and rheological properties of polymer/gas mixtures is critically important. This paper focuses on the pure PLA 3001D volume swelling measurement and its comparison with varying talc content. Effect of D content on swelling ratio is also discussed.
THERMOFORMABLE LIQUID CRYSTAL POLYMER (LCP)
Bing Lu, Achim Hofmann, Paul Yung, May 2012
Thermoforming is an economical process for forming large shape products. High performance liquid crystal polymer (LCP) has high thermal stability, excellent dimensional stability and high chemical resistance, which offers new application opportunities in demanding applications. In this paper, a new thermoformable LCP resin is compared with injection molding LCP on mechanical, thermal and rheological properties. Sheet extrusion and thermoforming process conditions are discussed.
THE EFFECT OF CO2 ON THE MELT FRACTURE BEHAVIOR OF FOAMED PLA
Lun Howe Mark, Mo Xu, Medhi Keshtkar, Chul B. Park, May 2012
The melt fracture behavior of foamed Polylactic acid (PLA) with the presence of blowing agent is studied in this investigation. A CCD camera is utilized to examine how foaming processing parameters such as blowing agent content, mass flow rate and temperature can affect melt fracture behavior. Images captured are used to analyze severity and nature of extrudate distortion.
PREDICTING CAPILLARY DIE SWELL OF HIGH MOLECULAR WEIGHT HDPE RESINS FOR BLOW MOLDING APPLICATIONS
Tieqi Li, Carmine D’Agostino, Wen Lin, Tracy Li, May 2012
Capillary die swell of high molecular weight HDPE resins was measured and compared to the prediction based on various rheological models. The predictions based on stress ratio per Leonov model tend to overestimate the capillary die swell while those through Wagner model underestimate. Predictions per Doi- Edwards model were applicable only at low shear rate. This study reveals the need to further assess damping parameters in addition to the relaxation spectrum.
GENERATION OF AN EMPIRICAL MODEL TO DESCRIBE THE EXPERIMENTAL EVOLUTION OF DRAG RATIO FOR A TWO PHASE HORIZONTAL PIPE FLOW OF NON-NEWTONIAN LIQUID (CARBOPOL)/AIR MIXTURE
Febin Cyriac, , J.M.Franco, M. Carmen Sánchez, May 2012
The prediction of the pressure drop gradient and the evaluation of the drag reduction phenomenon observed during the piping multiphase flow of a Carbopol/Air mixture have been investigated. Viscous flow tests in rotational rheometers and pressure drop measurements in pipe lines have been carried out with both smooth and rough surfaces. The Power law model is used to predict the pressure drop gradient. The pressure drop gradient in the intermittent multiphase flow regimes can be predicted by modifying the classical approach of Lockhart and Martinelli with an empirical correction factor. An Empirical model with quadratic equation has been proposed to describe the experimental evolution of drag ratio as a function of Re'L / Re'TP.
RHEOLOGY AND MELT FRACTURE OF BIODEGRADABLE POLY (?-CAPROLACTONE) POLYESTERS
Nazbanoo Noroozi, Jaclyn A. Thomson, Laurel L. Schafer, Savvas G. Hatzikiriakos, May 2012
The viscoelastic behaviour of a number of commercial and newly synthesized linear biodegradable polyesters - poly (?-caprolactone) (PCLs) with different molecular characteristics was investigated using both rotational and capillary rheometry. The variation of the zero-shear viscosity and relaxation spectrum with molecular weight was studied in detail. The PCL processing instabilities were studied by capillary extrusion using a number of capillary dies having various diameter and length-to- diameter ratios. Sharkskin and gross melt fracture was observed at different shear rates depending on the molecular characteristics of the resins and the geometrical details of the capillary dies.
DEVELOPMENT OF A METHOD FOR MEASURING THE THERMAL CONTACT RESISTANCE AND THERMAL CONDUCTIVITY OF ELECTRONIC MOLDING COMPOUNDS
Tamas Deak, David Kazmer, Norbert Kovacs, May 2012
The process simulation of thermoset molding processes (e.g. transfer molding, liquid injection molding) becomes increasingly important, because it can significantly reduce the cost of product development. This demands the correct determination of heat transfer and rheological coefficients. The aim of this study was the designing and construction of an apparatus which can measure the thermal contact resistance and thermal conductivity of epoxy molding compounds in the same circumstances which they encounter during processing.
EFFECT OF NANOCLAYS ON THE COMPATIBILITY OF MALEIC ANHYDRIDE-GRAFTED-POLYPROPYLENE/POLY (ETHYLENE OXIDE) BLEND
Abdulhadi A. Al-Juhani, May 2012
This study investigated the effect of surface modification of nanoclays on the compatibility of Maleic Anhydride-grafted polypropylene (PP-g-MA)/poly (ethylene oxide) (PEO) blends. Rheological testing confirmed the network formation of nanaoclays of all types. SEM confirmed the emulsifying role of nanoclays by reducing the PEO domain size. For the case of using dialkyl (C18)-modified nanoclays, mechanical testing showed that the elastic modulus and the toughness were respectively improved by 20% and 55% compared to unfilled samples.
FLOW BEHAVIOR OF DIFFERENT POLYETHYLENES IN CAPILLARY FLOW
Evan Mitsoulis, Thanasis Zisis, Mahmoud Ansari, Savvas G. Hatzikiriakos, May 2012
Three major polyethylene (PE) engineering plastics, linear-low-density (LLDPE), low-density (LDPE) and high- density (HDPE) are studied in capillary flow. The purpose is to find experimentally and predict numerically their flow behaviour, namely the pressure drop in flow through tapered dies. This behavior is related to their individual rheological and flow properties. Using a series of capillary dies having different diameters D and length-to-diameter L/D ratios, a full rheological characterization has been carried out, and the experimental data have been fitted with the viscoelastic K-BKZ/PSM model. The branched LDPE has a strong pressure-dependence of viscosity, with a pressure-dependent coefficient ?p. For the linear LLDPE and HDPE melts, the pressure-dependence of viscosity is weak, but slip at the wall is strong and affects their flow behaviour. Thermal effects due to viscous dissipation are included but are rather mild. It is found that the viscoelastic simulations are capable of reproducing the experimental data well, in the whole range of apparent shear rates and L/D ratios.
MISCIBILITY CHARACTERIZATION OF INDOMETHACIN AND EUDRAGIT® E PO BY RHEOLOGICAL AND THERMAL ANALYSIS
Huiju Liu, Herman Suwardie, Xueyan Zhang, Peng Wang, Costas G. Gogos, May 2012
The miscibility between drug indomethacin and excipient Eudragit® E PO were extensively characterized by rheological and thermal analysis. The evolution of glass transition temperature and activation energy with indomethacin concentration indicates the existence of overall positive deviation which represents anti-plasticization effect. The rheological analysis is in agreement with the thermal analysis, and both methods indicate that the miscibility between them is very good for indomethacin concentrations up to 60~70%.
COMPARATIVE THERMAL AND RHEOLOGICAL STUDY OF AROMATIC AND ALIPHATIC POLYAMIDE NANOCOMPOSITES AND FILMS
Matyam Fereydoon, Seyed H. Tabatabaei, Abdellah Ajji, May 2012
In this study, thermal and rheological properties of polyamide 6 (PA6), poly (m-xylene adipamide) (MXD6) and their commercial nanocomposites (4 wt.% clay) were studied. Dynamic rheological experiments were carried out for both neat resins and corresponding nanocomposites at different temperatures. Rheological measurements were conducted using a strain-controlled rheometer. Crystallinity and thermal transitions of the materials are established via both DSC and XRD techniques. Oxygen transmission rates were also measured and normalized by the films thickness.
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