scholarly journals Thermoplastic Dynamic Vulcanizates with In Situ Synthesized Segmented Polyurethane Matrix

Polymers ◽  
2019 ◽  
Vol 11 (10) ◽  
pp. 1663 ◽  
Author(s):  
Andrea Kohári ◽  
István Zoltán Halász ◽  
Tamás Bárány
Keyword(s):  
Mechanical Properties ◽  
Butadiene Rubber ◽  
Scanning Calorimetry ◽  
Dynamic Vulcanization ◽  
Sem Images ◽  
Acrylonitrile Butadiene Rubber ◽  
Atomic Force ◽  
Rubber Particles ◽  
Rubber Phase

The aim of this paper was the detailed investigation of the properties of one-shot bulk polymerized thermoplastic polyurethanes (TPUs) produced with different processing temperatures and the properties of thermoplastic dynamic vulcanizates (TDVs) made by utilizing such in situ synthetized TPUs as their matrix polymer. We combined TPUs and conventional crosslinked rubbers in order to create TDVs by dynamic vulcanization in an internal mixer. The rubber phase was based on three different rubber types: acrylonitrile butadiene rubber (NBR), carboxylated acrylonitrile butadiene rubber (XNBR), and epoxidized natural rubber (ENR). Our goal was to investigate the effect of different processing conditions and material combinations on the properties of the resulting TDVs with the opportunity of improving the interfacial connection between the two phases by chemically bonding the crosslinked rubber phase to the TPU matrix. Therefore, the matrix TPU was synthesized in situ during compounding from diisocyanate, diol, and polyol in parallel with the dynamic vulcanization of the rubber mixture. The mechanical properties were examined by tensile and dynamical mechanical analysis (DMTA) tests. The morphology of the resulting TDVs was studied by atomic force microscopy (AFM) and scanning electron microscopy (SEM) and the thermal properties by differential scanning calorimetry (DSC). Based on these results, the initial temperature of 125 °C is the most suitable for the production of TDVs. Based on the atomic force micrographs, it can be assumed that phase separation occurred in the TPU matrix and we managed to evenly distribute the rubber phase in the TDVs. However, based on the SEM images, these dispersed rubber particles tended to agglomerate and form a quasi-continuous secondary phase where rubber particles were held together by secondary forces (dipole–dipole and hydrogen bonding) and can be broken up reversibly by heat and/or shear. In terms of mechanical properties, the TDVs we produced are on a par with commercially available TDVs with similar hardness.

Epoxidized polybutadiene rubber as an effective compatibilizer for acrylonitrile butadiene rubber and polybutadiene rubber blend

2021 ◽  
pp. 009524432110171
Author(s):  
Vivek K Srivastava ◽  
Ganesh C Basak ◽  
Sukdeb Saha ◽  
GS Srinivasa Rao ◽  
Raksh Vir Jasra
Keyword(s):  
Mechanical Properties ◽  
Tensile Modulus ◽  
Butadiene Rubber ◽  
Scanning Calorimetry ◽  
Elongation At Break ◽  
Force Microscopy ◽  
Acrylonitrile Butadiene Rubber ◽  
Atomic Force ◽  
Polybutadiene Rubber ◽  
Compatibilized Blends

In the present study, epoxidized polybutadiene rubber (EBR; 30 mol% epoxidation) was synthesized using commercial-grade cis-polybutadiene rubber (BR). The EBR was successfully utilized as an effective compatibilizer between two incompatible elastomers, namely polar acrylonitrile butadiene rubber (NBR) and non-polar polybutadiene rubber (BR). The NBR and BR were blended in varied formulations and studied for morphological and mechanical properties. The observed properties of the blends containing EBR, as a compatibilizer, were compared with analogous blends without EBR. The optimum loading of EBR in NBR/BR formulations was found to be 5 phr (parts per hundred gram of rubber). The significant improvement in various mechanical properties such as tensile strength, tensile modulus, elongation at break and hardness were observed in presence of optimum loading of EBR in NBR/BR blends. Atomic Force Microscopy (AFM), Differential Scanning Calorimetry (DSC) and Dynamic Mechanical Analyser (DMA) studies revealed that the compatibility between two incompatible rubbers improved in the presence of EBR. The results observed with EBR-compatibilized blends revealed that EBR can be used as an effective compatibilizer between two incompatible rubbers (NBR and BR).

scholarly journals Development of Polypropylene-based Thermoplastic Elastomers with Crumb Rubber by Dynamic Vulcanization: A Potential Route for Rubber Recycling

2019 ◽  
Vol 64 (2) ◽  
pp. 248-254
Author(s):  
István Zoltán Halász ◽  
Dávid Kocsis ◽  
Dániel Ábel Simon ◽  
Andrea Kohári ◽  
Tamás Bárány
Keyword(s):  
Mechanical Properties ◽  
Mechanical Performance ◽  
Crumb Rubber ◽  
Thermoplastic Elastomers ◽  
Partial Replacement ◽  
Styrene Butadiene Rubber ◽  
Butadiene Rubber ◽  
Dynamic Vulcanization ◽  
Screw Speed ◽  
Rubber Phase

In our current paper the preparation and properties of thermoplastic elastomer produced by dynamic vulcanization is presented and discussed. We dynamically vulcanized natural and styrene butadiene rubber (NR/SBR) phase by continuous extrusion. Dispersion and in-situ vulcanization of the rubber phase occurred simultaneously in a co-rotating twin screw extruder. We used a random polypropylene copolymer (rPP) as the thermoplastic matrix and untreated crumb rubber (CR) to partially substitute the neat fresh rubber in order to check whether this is a potential recycling route for waste rubber products. We studied the effect of various rubber formulations, various processing conditions (screw speed and configuration) and various CR particle size distributions by characterizing the mechanical performance of the thermoplastic dynamic vulcanizates (TDVs) with tensile and hardness tests and their morphology by evaluating SEM micrographs taken from the fracture surfaces of the tensile specimens. The results showed that increasing screw speed and more high-shear elements in the screw setup led to a finer dispersion of the rubber phase, resulting in improved mechanical properties. The ultimate tensile properties of the best TDVs reached 20.5 MPa in tensile strength and 550 % in strain at break. However, partial replacement of the fresh rubber with untreated CR caused a significant deterioration in mechanical properties, due to poor adhesion between the CR particles and the matrix and rubber. This suggests that some kind of pre-treatment (e.g. by microwave or other devulcanization techniques) is necessary to enhance the surface activity of the CR particles.

Blends of Nylon 6/66 and Acrylonitrile-Butadiene Rubber: Effects of Blend Ratio and Dynamic Vulcanization on Morphology and Properties

2005 ◽  
Vol 21 (4) ◽  
pp. 277-297 ◽  
Author(s):  
C. Radhesh Kumar ◽  
I. Aravind ◽  
R. Stephan ◽  
Peter Koshy ◽  
J. Jose ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Butadiene Rubber ◽  
Dynamic Vulcanization ◽  
Blend Ratio ◽  
Acrylonitrile Butadiene Rubber ◽  
Electron Microscopies ◽  
Blend Morphology ◽  
Transmission Electron ◽  
The Stability ◽  
Morphology And Mechanical Properties

The morphology and mechanical properties of nylon (copolyamide 6/66)/ acrylonitrile-butadiene rubber (NBR) blends have been studied with special reference to the effect of blend ratio and crosslinking systems. Morphological investigations of the blends using scanning and transmission electron microscopies show that a uniform and finer dispersion of the elastomer phase is achieved by dynamic crosslinking. The effects of various crosslinking systems such as sulphur and dicumyl peroxide on the morphology and mechanical properties of these blends were analysed. Morphological stability of the blends upon annealing has been investigated and the mechanical properties of the blends have been discussed. Attempts have been made to correlate the morphology with the mechanical properties of the dynamically vulcanized blends. The stability of the blend morphology during annealing has been examined.

Investigating hollow corundum microspheres exfoliation of the elastomeric matrix

2019 ◽  
pp. 135-142
Author(s):  
N. V. Shadrinov ◽  
U. V. Evseeva
Keyword(s):  
Mechanical Properties ◽  
Atomic Force Microscope ◽  
Butadiene Rubber ◽  
Nitrile Butadiene Rubber ◽  
Elastomeric Matrix ◽  
Atomic Force

The results of study of the influence of hollow corundum microspheres HCM-S (5–100 µm) and HCM-L (70–180 µm) on the properties of nitrile butadiene rubber BNKS-18 are presented. The dependence of elastomer resistance to abrasion impact and physic and mechanical properties on the dispersion and concentration of hollow corundum microspheres is shown. The process of hollow corundum microspheres exfoliation of the elastomeric matrix, which largely determines the change of physic and mechanical properties, has been studied by specially developed stretching device compatible with an atomic force microscope. The paper describes microspheres exfoliation which is conventionally divided into 3 stages.

scholarly journals Microstructure and mechanical properties of slowly cooled Cu47.5Zr47.5Al5

2007 ◽  
Vol 22 (2) ◽  
pp. 326-333 ◽  
Author(s):  
J. Das ◽  
S. Pauly ◽  
C. Duhamel ◽  
B.C. Wei ◽  
J. Eckert
Keyword(s):  
Mechanical Properties ◽  
Fracture Strain ◽  
Volume Fraction ◽  
Spherical Shape ◽  
High Yield ◽  
High Yield Strength ◽  
Scanning Calorimetry ◽  
Arc Melting ◽  
Martensite Matrix

Cu47.5Zr47.5Al5 was prepared by arc melting and solidified in situ by suction casting into 2–5-mm-diameter rods under various cooling rates (200–2000 K/s). The microstructure was investigated along the length of the rods by electron microscopy, differential scanning calorimetry and mechanical properties were investigated under compression. The microstructure of differently prepared specimens consists of macroscopic spherical shape chemically inhomogeneous regions together with a low volume fraction of randomly distributed CuZr B2 phase embedded in a 2–7 nm size clustered “glassy-martensite” matrix. The as-cast specimens show high yield strength (1721 MPa), pronounced work-hardening behavior up to 2116 MPa and large fracture strain up to 12.1–15.1%. The fracture strain decreases with increasing casting diameter. The presence of chemical inhomogenities and nanoscale “glassy-martensite” features are beneficial for improving the inherent ductility of the metallic glass.

scholarly journals A method for pet mechanical properties enhancement

2019 ◽  
Vol 10 (8) ◽  
pp. 1725
Author(s):  
Raffaella Aversa ◽  
Relly Victoria Virgil Petrescu ◽  
Antonio Apicella ◽  
Florian Ion Tiberiu Petrescu
Keyword(s):  
Mechanical Properties ◽  
Liquid Crystalline ◽  
Liquid Crystalline Polymers ◽  
Molecular Structures ◽  
Reactive Blending ◽  
Scanning Calorimetry ◽  
Shear Transfer ◽  
Crystalline Polymers ◽  
Reactive Compatibilizer

A method for PET mechanical properties enhancement by reactive blending with HBA/HNA Liquid Crystalline Polymers for in situ highly fibrillar composites preparation is presented. LCP/PET blends were reactively extruded in presence of Pyromellitic Di-Anhydride (PMDA) and then characterized by Differential Scanning Calorimetry, Thermally Stimulated Currents and tensile mechanical properties. Moderate amounts of LCP in the PET (0.5 and 5%) and small amounts of thermo-active and reactive compatibilizer in the blend (0.3%) were found to significantly improve LCP melt dispersion, melts shear transfer and LCP fibril formation and adhesion. An unexpected improvement was probably due to the presence of two distinct phases’ supra-molecular structures involving PET-LCP and PMDA.

Influence of acrylonitrile butadiene rubber on recyclability of blends prepared from poly(vinyl chloride) and poly(methyl methacrylate)

2018 ◽  
Vol 36 (6) ◽  
pp. 495-504 ◽  
Author(s):  
Sunil S Suresh ◽  
Smita Mohanty ◽  
Sanjay K Nayak
Keyword(s):  
Methyl Methacrylate ◽  
Vinyl Chloride ◽  
Butadiene Rubber ◽  
Scanning Calorimetry ◽  
Elongation At Break ◽  
Poly Methyl Methacrylate ◽  
Impact Performance ◽  
Acrylonitrile Butadiene Rubber ◽  
Poly Vinyl Chloride ◽  
Spectroscopy Studies

The current investigation deals with the recycling possibilities of poly(vinyl chloride) and poly(methyl methacrylate) in the presence of acrylonitrile butadiene rubber. Recycled blends of poly(vinyl chloride)/poly(methyl methacrylate) are successfully formed from the plastic constituents, those are recovered from waste computer products. However, lower impact performance of the blend and lower stability of the poly(vinyl chloride) phase in the recycled blend restricts its further usage in industrial purposes. Therefore, effective utilisation acrylonitrile butadiene rubber in a recycled blend was considered for improving mechanical and thermal performance. Incorporation of acrylonitrile butadiene rubber resulted in the improvement in impact performance as well as elongation-at-break of the recycled blend. The optimum impact performance was found in the blend with 9 wt% acrylonitrile butadiene rubber, which shows 363% of enhancement as compared with its parent blend. Moreover, incorporated acrylonitrile butadiene rubber also stabilises the poly(vinyl chloride) phase present in the recycled blend, similarly Fourier transform infrared spectroscopy studies indicate the interactions of various functionalities present in the recycled blend and acrylonitrile butadiene rubber. In addition to this, thermogravimetric analysis indicates the improvement in the thermal stability of the recycled blend after the addition of acrylonitrile butadiene rubber into it. The existence of partial miscibility in the recycled blend was identified using differential scanning calorimetry and scanning electron microscopy.

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