scholarly journals Melt Rheology of Renewable Polymers and of New Materials Based on them as Tool in Controlling the 3D/4D Printability

2021 ◽  
Vol 57 (4) ◽  
pp. 77-87
Author(s):  
Doina Dimonie ◽  
Nicoleta Dragomir
Keyword(s):  
Molecular Weight ◽  
Melt Flow Index ◽  
Melt Processing ◽  
Operating Conditions ◽  
Flow Index ◽  
Flow Conditions ◽  
Index Method ◽  
Pre Treatment ◽  
Processing Techniques ◽  
Selection Of

The article presents results regarding the use of the melt flow index method (MFIM) in estimating the rheological properties of polylactic acid (PLA) and PLA-based materials, as tool in the selection of the operating conditions at their shaping into filaments and for 3D printing with thus obtained filaments. Based on the MFIM, the molecular weight of various PLA grade commonly used in melt processing techniques, including printing, were qualitatively compared. It was found that PLA for printing has the lowest molecular weight as compared with the PLA melt processed through injection, extrusion, thermoforming. It has been also shown that the MFIM can be used to verify the efficiency of drying, pre-treatment always needed to be done, before filaments obtaining and/or printing, especially in case of renewable polyesters. By simulating the printing at the indexer, via depositing successive layers, one over the other, it was possible to estimate the optimal flow conditions that ensure a good adhesion between the deposited layers. The estimation of the condition which ensure the needed adhesion between the deposited layers with the help of the MFIM was verified with good results on a grade of high loaded PLA achieved according to an original formulation.

scholarly journals Mechanical, Thermal and Rheological Properties of Polyethylene-Based Composites Filled with Micrometric Aluminum Powder

Materials ◽  
2020 ◽  
Vol 13 (5) ◽  
pp. 1242
Author(s):  
Olga Mysiukiewicz ◽  
Paulina Kosmela ◽  
Mateusz Barczewski ◽  
Aleksander Hejna
Keyword(s):  
Mechanical Properties ◽  
Melt Flow Index ◽  
Tensile Tests ◽  
Mechanical Analysis ◽  
Flow Index ◽  
Scanning Calorimetry ◽  
Metal Composites ◽  
Pre Treatment ◽  
The Impact ◽  
Properties Of Composites

Investigations related to polymer/metal composites are often limited to the analysis of the electrical and thermal conductivity of the materials. The presented study aims to analyze the impact of aluminum (Al) filler content (from 1 to 20 wt%) on the rarely investigated properties of composites based on the high-density polyethylene (HDPE) matrix. The crystalline structure, rheological (melt flow index and oscillatory rheometry), thermal (differential scanning calorimetry), as well as static (tensile tests, hardness, rebound resilience) and dynamic (dynamical mechanical analysis) mechanical properties of composites were investigated. The incorporation of 1 and 2 wt% of aluminum filler resulted in small enhancements of mechanical properties, while loadings of 5 and 10 wt% provided materials with a similar performance to neat HDPE. Such results were supported by the lack of disturbances in the rheological behavior of composites. The presented results indicate that a significant content of aluminum filler may be introduced into the HDPE matrix without additional pre-treatment and does not cause the deterioration of composites’ performance, which should be considered beneficial when engineering PE/metal composites.

Processability predictions for mechanically recycled blends of linear polymers

2020 ◽  
Vol 40 (9) ◽  
pp. 771-781
Author(s):  
Janne van Gisbergen ◽  
Jaap den Doelder
Keyword(s):  
Molecular Weight ◽  
Circular Economy ◽  
Melt Flow Index ◽  
Building Blocks ◽  
Experimental Designs ◽  
New Method ◽  
Flow Index ◽  
Linear Polymers ◽  
Combined Method

AbstractRecycling of thermoplastic polymers is an important element of sustainable circular economy practices. The quality of mechanically recycled polymers is a concern. A method is presented to predict the structure and processability of recycled blends of polymers based on processability knowledge of their virgin precursor components. Blending rules at molecular weight distribution level are well established and form the foundation of the new method. Two essential fundamental building blocks are combined with this foundation. First, component and blend structure are related to viscosity via tube theories. Second, viscosity is related to melt flow index via a continuum mechanics approach. Emulator equations are built based on virtual experimental designs for fast forward and reverse calculations directly relating structure to viscosity and processability. The new combined method is compared with empirical blend rules, and shows important similarities and also clear quantitative differences. Finally, the new method is applied to practical recycling quality challenges.

Melt Processed Polymer Blends for Potential Regenerative Medicine Applications

2014 ◽  
Vol 679 ◽  
pp. 92-100
Author(s):  
Elaine Kenny ◽  
Declan M. Devine ◽  
Clement L. Higginbotham ◽  
Luke M. Geever
Keyword(s):  
Molecular Weight ◽  
Differential Scanning Calorimetry ◽  
Regenerative Medicine ◽  
Polyethylene Oxide ◽  
Melt Flow Index ◽  
Flow Index ◽  
Biodegradable Implants ◽  
Scanning Calorimetry ◽  
Breakdown Rate

There is an urgent and unmet requirement for biocompatible and biodegradable implants that gradually resorb when implanted in vivo. This study examines the potential of melt extruded thermoplastics polyethylene oxide (PEO) and polycaprolactone (PCL) in the area of regenerative medicine. Various ratios of PEO and PCL were melt blended and analysed in order to obtain an optimised breakdown rate. Subsequently the effect of varying the molecular weight of PCL using a constant molecular weight PEO was also examined. Samples were characterised using melt flow index (MFI), differential scanning calorimetry (DSC) and breakdown analysis. It was found that by altering both the concentrations of PEO/PCL and the molecular weight of PCL, melt viscosity, breakdown rate and thermal properties could be modulated to produce potential implant materials with a tailored breakdown rate.

On secondary recycling of ZrO2-reinforced HDPE filament prepared from domestic waste for possible 3-D printing of bearings

2019 ◽  
pp. 089270571986462 ◽  
Author(s):  
Rupinder Singh ◽  
Ranvijay Kumar ◽  
Shubham Tiwari ◽  
Shubham Vishwakarma ◽  
Shivam Kakkar ◽  
...  
Keyword(s):  
Acrylonitrile Butadiene Styrene ◽  
Melt Flow Index ◽  
Melt Processing ◽  
Thermoplastic Composites ◽  
Flow Index ◽  
Wear Properties ◽  
Twin Screw Extrusion ◽  
Screw Extrusion ◽  
Twin Screw ◽  
Recycled Hdpe

In this study, an innovative route for secondary recycling (with zirconium oxide (ZrO2) reinforcement) has been proposed based on melt processing of high-density polyethylene (HDPE) in low-temperature bearing applications. Initially, secondary recycled HDPE, acrylonitrile butadiene styrene, and nylon 6 thermoplastic composites were investigated for melt flow index (MFI) according to ASTM D1238 standard. Based on the acceptable MFI, secondary recycled HDPE matrix was selected for second-stage processing on twin screw extrusion (TSE). The final process involves reinforcement of ZrO2 into HDPE matrix by TSE in 60:40 ratio (by weight %) for preparation of feedstock filament (for possible 3-D printing of bearings). The results of the study suggest that for processing of HDPE, 40% ZrO2 composite matrix, 50 r min−1 screw speed, 190°C barrel temperature, and 15 kg applied load are the best setting of TSE (for maximizing the tensile strength of feedstock filament). The results are also supported by wear properties, thermal stability, and morphological analysis (based on scanning electron microscopy and electron-dispersive X-ray analysis).

scholarly journals Reactive Extrusion of Maleic-Anhydride-Grafted Polypropylene by Torque Rheometer and Its Application as Compatibilizer

Polymers ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 495
Author(s):  
Asra Tariq ◽  
Nasir M. Ahmad ◽  
Muhammad Asad Abbas ◽  
M Fayzan Shakir ◽  
Zubair Khaliq ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Maleic Anhydride ◽  
Benzoyl Peroxide ◽  
Melt Flow Index ◽  
Reactive Extrusion ◽  
Side Chain ◽  
Flow Index ◽  
Viscosity Change ◽  
Chain Reactions ◽  
Molecular Weight Product

This study is based upon the functionalization of polypropylene (PP) by radical polymerization to optimize its properties by influencing its molecular weight. Grafting of PP was done at different concentrations of maleic anhydride (MAH) and benzoyl peroxide (BPO). The effect on viscosity during and after the reaction was studied by torque rheometer and melt flow index. Results showed that a higher concentration of BPO led to excessive side-chain reactions. At a high percentage of grafting, lower molecular weight product was produced, which was analyzed by viscosity change during and after the reaction. Percentage crystallinity increased by grafting due to the shorter chains, which consequently led to an improvement in the chain’s packing. Prepared Maleic anhydride grafted polypropylene (MAH-g-PP) enhanced interactions in PP-PET blends caused a partially homogeneous blend with less voids.

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.

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