scholarly journals Plasticization and Morphology Development in Dynamically Vulcanized Thermoplastic Elastomers

10.5772/61414 ◽  
2015 ◽  
Author(s):  
Shant Shahbikian ◽  
Pierre J. Carreau
Keyword(s):  
Thermoplastic Elastomers ◽  
Morphology Development

Formation of Rubber Particle Agglomerates During Morphology Development in Dynamically Crosslinked EPDM/PP Thermoplastic Elastomers. Part 1: Effects of Processing and Polymer Structural Parameters

2003 ◽  
Vol 76 (1) ◽  
pp. 239-252 ◽  
Author(s):  
F. Goharpey ◽  
A. A. Katbab ◽  
H. Nazockdast
Keyword(s):  
Interfacial Adhesion ◽  
Structural Parameters ◽  
Rubber Particle ◽  
Thermoplastic Elastomers ◽  
Rubber Content ◽  
Morphology Development ◽  
Dynamic Loss ◽  
Two Phases ◽  
Tan Δ ◽  
Rubber Aggregates

Abstract Formation of agglomerate structure by the rubber particles through flocculation or networking mechanism during dynamic crosslinking of thermoplastic elastomers based on EPDM rubber and polypropylene has been evidenced. Scanning electron microscopy (SEM) examination performed on the crosslinked blend samples which had been etched by hot xylene suggested that agglomeration occurs mainly through a joint shell mechanism. Reduction of the mixing torque after passing the peak maximum at the dynamic crosslinking stage was concluded to be due to the shear induced breaking down of agglomerates leading to a more defined morphology. Samples removed after the maximum mixing torque showed higher dynamic loss tangent (tan δ) above the PP glass transition. This is attributed to the broadening of the retardation time spectra for the PP matrix in the blend system. Higher mixing torque, higher tensile strength, as well as better extensibility were found for the blend samples based on PP with low MFI value as a result of higher density of aggregates and more extent of their interfacial adhesion with the PP matrix. More defined morphology and higher rate of network breakdown was observed at high mixing shear rate. Mixing torque increased significantly with increasing the rubber content of the blend system from 40% to 60% (W : W) as a consequence of higher interaction of rubber aggregates with the PP matrix. Based on the obtained results, the structure of the rubber aggregates and associated networks as well as extent of interaction between the two phases play an important role in controlling the final morphology, processing behavior and therefore mechanical properties of the dynamically cured blend system.

Study on Parameters Affecting the Morphology Development of Dynamically Vulcanized Thermoplastic Elastomers Based on EPDM/PP in a Co-Rotating Twin Screw Extruder

2004 ◽  
Vol 77 (5) ◽  
pp. 847-855 ◽  
Author(s):  
S. Shafiei Sararoudi ◽  
H. Nazockdast ◽  
A. A. Katbab
Keyword(s):  
Flow Behavior ◽  
Thermoplastic Elastomers ◽  
Twin Screw Extruder ◽  
Screw Extruder ◽  
Dynamic Vulcanization ◽  
Screw Speed ◽  
Blend Composition ◽  
Morphological Studies ◽  
Twin Screw ◽  
Morphology Development

Abstract The morphology development of dynamically vulcanized thermoplastic elastomers (TPVs) based on EPDM/PP in a modular intermeshing co-rotating twin screw extruder was studied. Effects of the blend composition and screw speed were considered. The morphological studies were carried out on the cryogenically fractured surface of the samples using Scanning Electron Microscopy (SEM) technique. The flow behavior and melt viscoelastic properties of the samples were also investigated by using Rheometric Mechanical Spectrometer (RMS). The SEM results from TPV samples produced in the twin screw extruder showed a matrix-disperse type morphology similar to those reported for the TPV samples prepared in an internal mixer. The dynamic vulcanization process imposed on the molten blends resulted in a remarkable increase in the steady state torque of the extruder whose extent was found to be dependent upon the EPDM content and screw speed. These results were explained in terms of an agglomerate structure formed between the cured rubber particles. The TPV samples, in particular the samples containing 60% of EPDM, showed a pronounced viscosity upturn and strong elastic modulus (G′) at low frequency range. It was demonstrated that these results in conjunction with the results of relaxation time distribution H(λ) of the samples can provide a great insight into understanding the role of the blend composition and the processing variables on morphology development in the TPV samples in the co-rotating twin screw extruder.

Thermoplastic Elastomers

2000 ◽  
Author(s):  
Sabet Abdou-Sabet ◽  
Hans-Georg Wussow ◽  
Larry M. Ryan ◽  
Lawrence Plummer ◽  
Didier Judas ◽  
...  
Keyword(s):  
Thermoplastic Elastomers

scholarly journals Optical, Structural, and Dielectric Properties of Composites Based on Thermoplastic Polymers of the Polyolefin and Polyurethane Type and BaTiO3 Nanoparticles

Materials ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 753
Author(s):  
M. Baibarac ◽  
A. Nila ◽  
I. Smaranda ◽  
M. Stroe ◽  
L. Stingescu ◽  
...  
Keyword(s):  
Crystallization Process ◽  
Weight Ratio ◽  
Thermoplastic Elastomers ◽  
Visible Spectral Range ◽  
X Ray Diffraction ◽  
Thermoplastic Polymers ◽  
The Matrix ◽  
Free Films ◽  
Batio3 Nanoparticles ◽  
Properties Of Composites

In this work, new films containing composite materials based on blends of thermoplastic polymers of the polyurethane (TPU) and polyolefin (TPO) type, in the absence and presence of BaTiO3 nanoparticles (NPs) with the size smaller 100 nm, were prepared. The vibrational properties of the free films depending on the weight ratio of the two thermoplastic polymers were studied. Our results demonstrate that these films are optically active, with strong, broad, and adjustable photoluminescence by varying the amount of TPU. The crystalline structure of BaTiO3 and the influence of thermoplastic polymers on the crystallization process of these inorganic NPs were determined by X-ray diffraction (XRD) studies. The vibrational changes induced in the thermoplastic polymer’s matrix of the BaTiO3 NPs were showcased by Raman scattering and FTIR spectroscopy. The incorporation of BaTiO3 NPs in the matrix of thermoplastic elastomers revealed the shift dependence of the photoluminescence (PL) band depending on the BaTiO3 NP concentration, which was capable of covering a wide visible spectral range. The dependencies of the dielectric relaxation phenomena with the weight of BaTiO3 NPs in thermoplastic polymers blends were also demonstrated.

scholarly journals Synthesis, Properties, and Biodegradability of Thermoplastic Elastomers Made from 2-Methyl-1,3-propanediol, Glutaric Acid and Lactide

Life ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 43
Author(s):  
Lamya Zahir ◽  
Takumitsu Kida ◽  
Ryo Tanaka ◽  
Yuushou Nakayama ◽  
Takeshi Shiono ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Glass Transition ◽  
Transition Temperature ◽  
Glass Transition Temperature ◽  
Glutaric Acid ◽  
Triblock Copolymers ◽  
Tensile Tests ◽  
Thermoplastic Elastomers ◽  
Proteinase K ◽  
Synthesis Properties

An innovative type of biodegradable thermoplastic elastomers with improved mechanical properties from very common and potentially renewable sources, poly(L-lactide)-b-poly(2-methyl-1,3-propylene glutarate)-b-poly(L-lactide) (PLA-b-PMPG-b-PLA)s, has been developed for the first time. PLA-b-PMPG-b-PLAs were synthesized by polycondensation of 2-methyl-1,3-propanediol and glutaric acid and successive ring-opening polymerization of L-lactide, where PMPG is an amorphous central block with low glass transition temperature and PLA is hard semicrystalline terminal blocks. The copolymers showed glass transition temperature at lower than −40 °C and melting temperature at 130–152 °C. The tensile tests of these copolymers were also performed to evaluate their mechanical properties. The degradation of the copolymers and PMPG by enzymes proteinase K and lipase PS were investigated. Microbial biodegradation in seawater was also performed at 27 °C. The triblock copolymers and PMPG homopolymer were found to show 9–15% biodegradation within 28 days, representing their relatively high biodegradability in seawater. The macromolecular structure of the triblock copolymers of PLA and PMPG can be controlled to tune their mechanical and biodegradation properties, demonstrating their potential use in various applications.

scholarly journals Morphology Development and Flow Characteristics during High Moisture Extrusion of a Plant-Based Meat Analogue

Foods ◽  
2021 ◽  
Vol 10 (8) ◽  
pp. 1753
Author(s):  
Patrick Wittek ◽  
Felix Ellwanger ◽  
Heike P. Karbstein ◽  
M. Azad Emin
Keyword(s):  
Transition Zone ◽  
Flow Characteristics ◽  
Phase System ◽  
Shear Stresses ◽  
High Moisture ◽  
Tensile Stresses ◽  
Morphology Development ◽  
A Minor ◽  
Multi Phase ◽  
High Moisture Extrusion

Plant-based meat analogues that mimic the characteristic structure and texture of meat are becoming increasingly popular. They can be produced by means of high moisture extrusion (HME), in which protein-rich raw materials are subjected to thermomechanical stresses in the extruder at high water content (>40%) and then forced through a cooling die. The cooling die, or generally the die section, is known to have a large influence on the products’ anisotropic structures, which are determined by the morphology of the underlying multi-phase system. However, the morphology development in the process and its relationship with the flow characteristics are not yet well understood and, therefore, investigated in this work. The results show that the underlying multi-phase system is already present in the screw section of the extruder. The morphology development mainly takes place in the tapered transition zone and the non-cooled zone, while the cooled zone only has a minor influence. The cross-sectional contraction and the cooling generate elongational flows and tensile stresses in the die section, whereas the highest tensile stresses are generated in the transition zone and are assumed to be the main factor for structure formation. Cooling also has an influence on the velocity gradients and, therefore, the shear stresses; the highest shear stresses are generated towards the die exit. The results further show that morphology development in the die section is mainly governed by deformation and orientation, while the breakup of phases appears to play a minor role. The size of the dispersed phase, i.e., size of individual particles, is presumably determined in the screw section and then stays the same over the die length. Overall, this study reveals that morphology development and flow characteristics need to be understood and controlled for a successful product design in HME, which, in turn, could be achieved by a targeted design of the extruders die section.

scholarly journals Correction to Semibatch Terpolymerization of Ethylene, Propylene, and 5-Ethylidene-2-norbornene: Heterogeneous High-Ethylene EPDM Thermoplastic Elastomers

2021 ◽  
Vol 54 (3) ◽  
pp. 1574-1574
Author(s):  
Giuseppe Leone ◽  
Giorgia Zanchin ◽  
Rocco Di Girolamo ◽  
Fabio De Stefano ◽  
Christian Lorber ◽  
...  
Keyword(s):  
Thermoplastic Elastomers ◽  
Ethylene Propylene
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