Evaluating the gas-laden ability of polymer melt under atmospheric conditions using a modified torque rheometer

2021 ◽  
pp. 0021955X2199735
Author(s):  
Xing-Yu Mei ◽  
Ying-Guo Zhou ◽  
Hong-Long Sun ◽  
Bin-Bin Dong ◽  
Chun-Tai Liu ◽  
...  
Keyword(s):  
Rheological Properties ◽  
High Density Polyethylene ◽  
Polymer Melts ◽  
Polymer Melt ◽  
Melt Flow Index ◽  
Flow Index ◽  
Atmospheric Conditions ◽  
Molding Machine ◽  
Rheological Measurement ◽  
Foaming Behavior

To investigate the effects of incorporating gas and the associated influencing factors on polymer melt, a method of evaluating the gas-laden ability using modified rheometric measurements was proposed. In this study, common and widely used thermoplastic materials—polypropylene (PP) and high-density polyethylene (HDPE), and their blends with different weight ratios—were selected, and the rheological properties of neat melt and gas-laden melts were tested using a modified torque rheometer. The foamed samples were also produced using a regular injection-molding machine, and the foamed morphology was examined by scanning electron microscope (SEM). The comparison of rheological curves of neat melt and gas-laden melt indicated that the incorporation of gas influenced the rheological properties of the gas-laden polymer melts as evidenced by a decrease of zero-rotational torque and an increase in the melt flow index. The results also suggested that the gas-laden ability of polymer melt could be evaluated quantitatively by the decay (due to desorption) of gas using the modified rheological measurement method. This study also demonstrated that the gas-laden ability can be used to predict the foaming behavior of polymer melts.

Preparation of high molecular weight and elastic copolyester by reactive extrusion with diisocyanate compound for laser printing process

2012 ◽  
Vol 32 (3) ◽  
Author(s):  
Hyung-Jin Roh ◽  
Doe Kim ◽  
Dong-Ho Lee ◽  
Keun-Byoung Yoon
Keyword(s):  
Rheological Properties ◽  
Loss Modulus ◽  
Complex Viscosity ◽  
Melt Flow Index ◽  
Reactive Extrusion ◽  
Flow Index ◽  
Printing Process ◽  
Laser Printing ◽  
Printing Processes ◽  
Trimethylol Propane

Abstract A branched copolyester was synthesized using dimethyl terephthalate (DMT), 2,2-bis[4-(2-hydroxypropoxy)phenyl]propane, ethylene glycol (EG) and 2-(hydroxymethyl)-2- ethylpropane-1,3-diol (trimethylol propane, TMP). The branched copolyester and p-phenylene diisocyanate (PPDI) were melt extruded to enhance the melt viscosity and elasticity for use as a toner binder in the laser printing process. The effects of PPDI content on melt, thermal and rheological properties of the chain-extended copolyester were investigated. The melt flow index (MI) decreased with increasing amount of PPDI, due to a reaction between the hydroxyl chain end and isocyanate group. The storage modulus, loss modulus and complex viscosity of the chain extended copolyester were higher and the modified Cole-Cole plots revealed the chain extended copolyester to have higher elasticity than that of the branched copolyester. The chain extended copolyester exhibited suitable melt and rheological properties for applications as a toner binder in the laser printing processes.

Thermal and Thermorheologic Characterization of Different Polyolefin Waste Fractions

2017 ◽  
Vol 907 ◽  
pp. 74-79
Author(s):  
Adela Lazar ◽  
Catalin Croitoru ◽  
Mircea Horia Tierean ◽  
Liana Sanda Baltes
Keyword(s):  
Molecular Mass ◽  
High Density Polyethylene ◽  
Melt Flow Index ◽  
Household Waste ◽  
Flow Index ◽  
Melt Flow ◽  
Polymer Waste ◽  
Lower Molecular Mass ◽  
Low Shear

In this study, melt flow index values from several household waste fractions containing mainly polypropylene and high-density polyethylene, were measured at 190 °C for polyethylene and 230 °C for polypropylene-rich fractions. High values of MFI (low shear viscosities) have been reported probably due to the lower molecular mass of the polymer waste and/or the presence of surfactant compounds on the surface of the polymer flakes. Also, by extruding the same batch in different cycles at the same temperature values, the number of processing cycles on which the polymer could be recycled has been determined.

Mixtures of Recycled Milk Pouches with a Virgin LDPE-LLDPE Blend

2005 ◽  
Vol 21 (3) ◽  
pp. 219-230 ◽  
Author(s):  
Arup Choudhury ◽  
Mandira Mukherjee ◽  
Basudam Adhikari
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Rheological Properties ◽  
Melt Flow Index ◽  
Flow Index ◽  
Thermal And Mechanical Properties ◽  
Melt Flow ◽  
Recycled Materials ◽  
Elongation At Break

The present investigation deals with the viability of the use of recycled milk pouch material, which is a 50:50 mixture of LDPE and LLDPE, and the scope for improvement of its properties by combining it with virgin LDPE-LLDPE (50/50). Melt flow index (MFI), rheological properties, thermal and mechanical properties of the pure materials and their formulated blends containing recycled milk pouches were studied. The properties of the recycled materials were not as satisfactory as those of the corresponding virgin materials. But a significant improvement in viscosity, crystallinity, tensile strength and elongation at break of the recycled LDPE-LLDPE material was achieved by blending it with the corresponding virgin LDPE-LLDPE blend.

Rotomolding and polyethylene composites with rotomolded lignocellulosic materials: A review

2020 ◽  
Vol 39 (11-12) ◽  
pp. 459-472
Author(s):  
Lumirca Del Valle Espinoza León ◽  
Viviane Alves Escocio ◽  
Leila Lea Yuan Visconte ◽  
Julio Cesar Jandorno Junior ◽  
Elen Beatriz Acordi Vasques Pacheco
Keyword(s):  
Maleic Anhydride ◽  
Polymer Matrix ◽  
Polymer Melt ◽  
Polymeric Materials ◽  
Melt Flow Index ◽  
Polymer Particle ◽  
Morphological Properties ◽  
Flow Index ◽  
Main Process ◽  
Wood Fibers

Rotomolding is a versatile process used in the manufacture of thermoplastic polymeric materials to produce large hollow plastic parts. The aim of this review article was to discuss the rotomolding process and show the properties of the polyethylene composite and rotomolded lignocellulosic fibers, which are processed for prolonged periods under temperature. The main process parameters studied are the shaft speed of the equipment, molding temperature, polymer particle size, polymer melt flow index, and amount of material, which must be well controlled to achieve a non-degraded product with homogeneous thickness and no porosity. Rotomolded composites containing sisal, pine, coir, banana, flax, and maple wood fibers, among others, have been evaluated primarily for their mechanical (impact, flexural, and tensile strength) and morphological properties. The type, content, and treatment of lignocellulosic fillers are the most widely studied variables in polyethylene-based rotomolded composites. Fiber content was the variable that most influenced mechanical properties, particularly impact strength and hardness due to the voids formed by the hydrodynamic volume between the polymer matrix and lignocellulosic filler. Chemical treatment of the fiber by mercerization with NaOH made it more hydrophobic and the addition of maleic anhydride-grafted polyethylene as a coupling agent improved the interfacial adhesion between the non-polar polymer matrix and polar filler. However, the best mechanical property results were obtained with the use of maleic anhydride-grafted polyethylene.

A study of novel viscous dissipation measurement for polymer melts in microchannels

2010 ◽  
Vol 224 (9) ◽  
pp. 2027-2035 ◽  
Author(s):  
B Xu ◽  
M Wang ◽  
T Yu ◽  
D Zhao
Keyword(s):  
Viscous Dissipation ◽  
High Density Polyethylene ◽  
Polymer Melts ◽  
Flow Characteristics ◽  
Rheological Behaviour ◽  
Polymer Melt ◽  
Experimental Results ◽  
Maximum Temperature ◽  
Number Of Factors ◽  
Different Temperatures

Studies on the rheological behaviour of polymer melts, flowing through microchannels, are complicated because a large number of factors affect the melt viscosity. One such factor, viscous dissipation, is investigated in the current work through a novel experimental technique that is used in determining the viscous dissipation of a polymer melt flowing through microchannels. Relative tests are conducted using melts of high-density polyethylene (HDPE) extruded through several capillary dies at different temperatures. Experimental results indicate that the temperature rises due to viscous dissipation increase with increasing shear rate. In addition, simulations considering viscous dissipation are carried out. The comparison of the experimental results with those predicted from the simulations at different melt temperatures indicates that the maximum temperature rise deviation is about 15 per cent. Therefore, the measurement method of viscous dissipation is available, which is helpful to better understand the flow characteristics of microchannels.

Functional dyeable polypropylene fabric development and process parameter optimization Part I: Dyeable modified polypropylene development with process parameter optimization

2021 ◽  
pp. 004051752098497
Author(s):  
Chung-Feng Jeffrey Kuo ◽  
Shih Hsiung Chen
Keyword(s):  
Melting Point ◽  
Parameter Optimization ◽  
Polymer Melt ◽  
Principal Component ◽  
Melt Flow Index ◽  
Process Parameter ◽  
Flow Index ◽  
Disperse Dye ◽  
Color Strength ◽  
Process Parameter Optimization

This study aims to develop dyeable modified polypropylene (PP) granules with disperse dye. The optimal dyeable modified PP granule process used polyester as a mixed copolymer. The purpose was to overcome the excessive difference between the polyester material melting point and PP melting point. The development of a low-melting modified co-polybutylene adipate terephthalate (Co-PBAT) was the key point. After the low-melting modified Co-PBAT was presented, PP and a PP grafting maleic anhydride compatibilizer were made into a composite by dual-screw mixing process. The disperse dye dyeability was reached by the molecular behavior of the Co-PBAT chain segment. The prepared material was applied to explore the thermal properties of modified ester pellets and the functional group was verified by Fourier infrared spectroscopy. In this study, the Taguchi method and principal component analysis were used to optimize the process parameter design of two quality characteristics; namely, the color strength and the polymer melt flow index (MFI). According to the results, the multi-quality optimization of the ester pellets consisted of a modified Co-PBAT melting point of 170°C, the modified Co-PBAT content of 9 wt%, the compatibilizer content of 3 wt%, and the mixing temperature of 205°C. The MFI of the regular PP polymer was 28.1 g/10 min, the color strength was 100 K/S. For the optimal process, the MFI of the PP/Co-PBAT dyeable granules was 37.88 g/10 min, and the color strength was 121.31 K/S. It could be observed that the developed polymer had good circulating workability and color strength.

scholarly journals Effects of Heating Temperature and Load Weight on Rheological Properties of Waste Plastic Cup

2021 ◽  
Vol 17 (1) ◽  
pp. 39-49
Author(s):  
Halimatuddahliana Nasution ◽  
Winny Winny
Keyword(s):  
Shear Stress ◽  
Shear Rate ◽  
Rheological Properties ◽  
Heating Temperature ◽  
Melt Flow Index ◽  
Flow Index ◽  
Melt Flow ◽  
Waste Plastic ◽  
Load Weight ◽  
Increasing Load

Analysis of heating temperature and load weight to the rheological properties of waste plastic cups is very important to gain fundamental understanding of the structure, characteristics, and processability of the material. The samples were tested using melt flow indexer. The heating temperature investigated were 180°C, 190°C, 200°C, 210°C, 220°C and 230°C, and the weight load were 1,875 g, 2,160 g, 2,835 g, 3,035 g and 3,450 g. The results obtained showed that the rheological properties of products such as melt flow index, shear stress and shear rate increased and the viscosity decreased with the increasing of heating temperature and load weight. For higher heating temperatures, the melt flow index, shear stress and shear rate of waste plastic cup increased significantly with the increasing load weight whereas the viscosity of waste plastic cup did not decrease significantly with the increasing load weight.

scholarly journals EFFECT OF POLYETHYLENE MOLECULAR MASS CHARACTERISTICS ON SLIP EFFECT

2016 ◽  
Vol 11 (5) ◽  
pp. 91-93
Author(s):  
A. A. Yurkin ◽  
I. D. Simonov-Emelyanov ◽  
P. V. Surikov ◽  
N. L. Shembel
Keyword(s):  
Molecular Weight ◽  
Molecular Mass ◽  
Rheological Properties ◽  
Melt Flow Index ◽  
Flow Index ◽  
Slip Effect ◽  
Melt Flow ◽  
Molecular Weight Characteristics ◽  
Different Temperatures ◽  
Different Molecular Weight

The rheological properties of polyethylene with different molecular weight characteristics were studied. Difference of molecular weight characteristics was found on the basis of melt flow index, and slip effect in the molten polyethylene flow was studied. The presence of slip effect is found in case of flowing polyethylene with a higher molecular weight in contrast to polyethylene with lower molecular weight at different temperatures. Changes of the slip effect parameters upon mixing polyethylenes with very much different molecular weight characteristics were studied.

scholarly journals New Evidences on the Process Sensitivity of Some Renewable Blends Based on Starch considering Their Melt Rheological Properties

2016 ◽  
Vol 2016 ◽  
pp. 1-10 ◽  
Author(s):  
Doina Dimonie ◽  
Marius Petrache ◽  
Celina Damian ◽  
Liliana Anton ◽  
Miruna Musat ◽  
...  
Keyword(s):  
Rheological Properties ◽  
Corn Starch ◽  
Polymeric Materials ◽  
Melt Flow Index ◽  
Melt Processing ◽  
Chemical Degradation ◽  
Flow Index ◽  
Cross Linking ◽  
Temperature Sensitive ◽  
Renewable Materials

The degradability and processability of new renewable materials based on starch and PVOH were studied using the melt flow index (MFI) method by measuring the melt rheological properties which depend not only on the extrusion conditions and material formulation but also on the macromolecule characteristics which can be modified by chemical degradation. These results were correlated with other material properties like color and cross-linking degree. The obtained results show that flowing in the melted state of the studied materials is accompanied by a second process of chains chemical degradation. It was observed that, at the same level of additivation, under identical extrusion conditions, the melted blends with corn starch as main component are highly mechanically sensitive and degrade mostly by chains scission and those with PVOH as major component are highly temperature sensitive and degrade mainly by cross-linking. The obtained results show also that each PVOH-starch blend requires particular formulation and individual windows of melt processing conditions. These results are a good proof that the MFI method is a good path to study the degradability and moldability of process sensitive polymeric materials like those based on starch and PVOH.

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