Comparison of superimposed effects in high-shear-rate capillary rheology of polystyrene, polypropylene, and linear low-density polyethylene melts

2014 ◽  
Vol 55 (3) ◽  
pp. 506-512 ◽  
Author(s):  
An-Fu Chen ◽  
Han-Xiong Huang ◽  
Wei-Sheng Guan
Keyword(s):  
Shear Rate ◽  
High Shear Rate ◽  
Low Density Polyethylene ◽  
Low Density ◽  
High Shear ◽  
Linear Low Density Polyethylene ◽  
Polyethylene Melts

A Comparison of Rheological Models and Experimental Data of Metallocene Linear Low Density Polyethylene Solutions as a Function of Temperature and Concentration

2016 ◽  
Vol 12 (3) ◽  
pp. 4322-4339
Author(s):  
Salah Hamza
Keyword(s):  
Experimental Data ◽  
Shear Rate ◽  
Rheological Properties ◽  
Power Law ◽  
Low Density Polyethylene ◽  
Effect Of Temperature ◽  
Low Density ◽  
Linear Low Density Polyethylene ◽  
Shear Rates ◽  
Wide Range

Knowledge of rheological properties of polymer and their variation with temperature and concentration have been globally important for processing and fabrication of polymers in order to make useful products. Basheer et al. [1] investigated, experimentally, the changes in rheological properties of metallocene linear low density polyethylene (mLLDPE) solutions by using a rotational rheometer model AR-G2 with parallel plate geometry. Their work covered the temperature range from  to  and  concentration from  to . In this paper, we reconsider Basheer work to describe the rheological behavior of mLLDPE solutions and its dependence on concentration and temperature.Until now, several models have been built to describe the complex behavior of polymer fluids with varying degrees of success. In this article, Oldroyd 4-constant, Giesekus and Power law models were tested for investigating the viscosity of mLLDPE solution as a function of shear rate. Results showed that Giesekus and power law models provide the best prediction of viscosity for a wide range of shear rates at constant temperature and concentration. Therefore, Giesekus and power law models were suitable for all mLLDPE solutions while Oldroyd 4-constant model doesn't.A new proposed correlation for the viscosity of mLLDPE solutions as a function of shear rate, temperature and concentration has been suggested. The effect of temperature and concentration can be adequately described by an Arrhenius-type and exponential function respectively. The proposed correlation form was found to fit the experimental data adequately.

scholarly journals Design and Synthesis of Polysiloxane Based Side Chain Liquid Crystal Polymer for Improving the Processability and Toughness of Magnesium Hydrate/Linear Low-Density Polyethylene Composites

Polymers ◽  
2020 ◽  
Vol 12 (4) ◽  
pp. 911
Author(s):  
Xiaoxiao Guan ◽  
Bo Cao ◽  
Jianan Cai ◽  
Zhenxing Ye ◽  
Xiang Lu ◽  
...  
Keyword(s):  
Liquid Crystal ◽  
Shear Rate ◽  
Decomposition Temperature ◽  
Liquid Crystal Polymer ◽  
Low Density Polyethylene ◽  
Processing Temperature ◽  
Low Density ◽  
Linear Low Density Polyethylene ◽  
Design And Synthesis ◽  
Crystal Polymer

In this study, a polysiloxane grafted by thermotropic liquid crystal polymer (PSCTLCP) is designed and synthesized to effectively improve the processability and toughness of magnesium hydroxide (MH)/linear low-density polyethylene (LLDPE) composites. The obtained PSCTLCP is a nematic liquid crystal polymer; the liquid crystal phase exists in a temperature range of 170 to 275 °C, and its initial thermal decomposition temperature is as high as 279.6 °C, which matches the processing temperature of MH/LLDPE composites. With the increase of PSCTLCP loading, the balance melt torque of MH/LLDPE/PSCTLCP composites is gradually decreased by 42% at 5 wt % PSCTLCP loading. Moreover, the power law index of MH/LLDPE/PSCTLCP composite melt is smaller than 1, but gradually increased with PSCTLCP, the flowing activation energy of PSCTLCP-1.0 is lower than that of MH/LLDPE at the same shear rate, indicating that the sensitivity of apparent melt viscosity of the composites to shear rate and to temperature is decreased with the increase of PSCTLCP, and the processing window is broadened by the addition of PSCTLCP. Besides, the elongation at break of MH/LLDPE/PSCTLCP composites increases from 6.85% of the baseline MH/LLDPE to 17.66% at 3 wt % PSCTLCP loading. All the results indicate that PSCTLCP can significantly improve the processability and toughness of MH/LLDPE composites.

RHEOLOGICAL CHARACTERISTICS OF NANOCOMPOSITES BASED ON CLINOPTILOLITE AND LINEAR POLYETHYLENE OF LOW DENSITY

2018 ◽  
Vol 61 (7) ◽  
pp. 106
Author(s):  
Najaf T. Kakhramanov ◽  
Neli S. Koseva ◽  
Rena V. Kurbanova ◽  
Ilaha V. Bayramova ◽  
Nushaba B. Arzumanova ◽  
...  
Keyword(s):  
Shear Rate ◽  
Polymer Matrix ◽  
Low Density Polyethylene ◽  
Low Density ◽  
Rheological Characteristics ◽  
Linear Low Density Polyethylene ◽  
Flow Curves ◽  
Linear Polyethylene ◽  
Natural Minerals ◽  
First Time

In the paper the results of the study of the influence of clinoptilolite concentration, shear stress and temperature on the effective viscosity, shear rate and activation energy of the viscous flow of nanocomposites based on linear low-density polyethylene were presented. It was shown that the in the composition of the natural mineral contains kaolinite or nanoclay. During the diffusion of macro chains into the interlayer space of nanoclays, the latter decays and the surfactant, exchanged cations or anions, stearates present there, as a result migrate into the polymer matrix and then, as lubricants, improve the flowability of the melt of the nanocomposite. For the first time it was shown that natural minerals of Azerbaijan belong to the number of bifunctional fillers, which contribute to the enhancement of polymer composites and, at the same time, improve the flowability of their melt. Rheological studies were carried out on the MELT FLOW TESTER, CEAST MF50 (INSTRON, Italy) capillary rheometer in the temperature range of 190-250 °C and the load of 2.16 -21.6 kg. The size of the nanoparticles of the composites was determined using the device model of STA PT1600 Linseiz, Germany, which varied from 14 to 110 nm. The nanoparticles of clinoptilolite were obtained in the analytical mill A-11 at the maximum rotor speed of 28,000 rpm. Flow curves of nanocomposites based on linear low density polyethylene and clinoptilolite were determined. It was established that introduction of 5% wt. clinoptilolite promotes an increase in shear rate 2.62 times. The results of the study of the influence of clinoptilolite concentration on the rheological and physico-mechanical characteristics of nanocomposites were presented. It was shown that when the concentration of clinoptilolite in the polymer matrix increases from 5 to 15 wt% the shear rate is somewhat reduced, but remains higher than that of the initial polyolefin.For citation:Kakhramanov N.T., Koseva N.S., Kurbanova R.V., Bayramova I.V., Arzumanova N.B., Ismailzade A.C. Rheological characteristics of nanocomposites based on clinoptilolite and linear polyethylene of low density. Izv. Vyssh. Uchebn. Zaved. Khim. Khim. Tekhnol. 2018. V. 61. N 7. P. 105-112 

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