RECLAIMING OF GROUND RUBBER TIRE BY SAFE MULTIFUNCTIONAL RUBBER ADDITIVES: II VIRGIN NATURAL RUBBER/RECLAIMED GROUND RUBBER TIRE VULCANIZATES

2014 ◽  
Vol 87 (1) ◽  
pp. 152-167 ◽  
Author(s):  
Swapan Kumar Mandal ◽  
Md Najib Alam ◽  
Kumarjyoti Roy ◽  
Subhas Chandra Debnath

ABSTRACT Mechanochemically reclaimed ground rubber tire (GRT) was revulcanized in combination with virgin natural rubber (NR). The NR/GRT vulcanizates with GRT content 20–50 wt% were prepared and studied. Reclaiming of GRT was successfully carried out by tetra benzyl thiuram disulfide (TBzTD) in the presence of spindle oil at around ambient temperature. The cure characteristics and mechanical properties of the virgin NR/reclaimed GRT blend were studied. Increasing the reclaimed rubber (RR) content in the blend decreases the optimum cure time without altering the scorch time. The effect of carbon black was studied in NR/RR (80/20) blend vulcanizate for the ultimate use of NR/RR blend vulcanizate. Aging characteristics of different NR/RR blends were evaluated. The swelling behavior, thermo-gravimetric analysis, and dynamic mechanical properties of NR/RR blend vulcanizates were examined. The equilibrium swelling of the NR vulcanizates was reduced with increasing reclaimed rubber content. Thermal stability of the blend vulcanizates was increased with increase in reclaimed rubber content. The elastic and storage modulus of the NR/RR vulcanizates improved with increasing reclaimed rubber content. Scanning electron microscopy studies further indicate the coherency and homogeneity in the NR/RR vulcanizate.

2009 ◽  
Vol 82 (5) ◽  
pp. 473-491 ◽  
Author(s):  
M. Tiwari ◽  
R. N. Datta ◽  
A. G. Talma ◽  
J. W. M. Noordermeer ◽  
W. K. Dierkes ◽  
...  

Abstract The surface characteristics of silica were modified by plasma-thiophene and -acetylene film deposition. The plasma-coated fillers were blended with S-SBR and EPDM, and their influence on the final vulcanizate properties was compared with untreated silica and silanized silica. The change in the surface energy of plasma-acetylene (PA) and thiophene- (PTh) coated silica was characterized by immersion tests in liquids of various surface tension, water penetration measurements, Thermo Gravimetric Analysis (TGA) and Time of Flight Secondary Ion Mass Spectroscopy (ToF-SIMS). All techniques gave evidence of a polymeric PA- and PTh-film deposition on the surface of silica. The properties of S-SBR and EPDM, filled with untreated, PA-, PTh- and silane-treated silica, were investigated by measurement of the Payne effect, bound rubber content and weight loss related to bound rubber, the reinforcement parameter, relative ranking of cross-link density and mechanical properties. The results show a lower degree of flocculation for PTh-silica filled EPDM due to a better match of the surface energies compared to untreated and PA-treated silica. EPDM filled with plasma-thiophene coated silica shows the lowest reinforcement parameter value, thus improved dispersion compared to untreated, silane-treated and plasma-acetylene silica. However, PA-silica filled EPDM shows better mechanical properties compared to untreated and plasma-thiophene coated silica. The PTh-silica filled S-SBR shows a higher bound rubber content, which results in better mechanical properties of the S-SBR compound compared to the one with PA-coated silica. The overall results show that the compatibility and interaction of silica with different rubbers can be controlled by tailoring the surface energy of the filler by plasma-polymerization. The different functionalities on the silica surface result in different levels of compatibility and interaction, as well as final vulcanizates properties.


2004 ◽  
Vol 77 (5) ◽  
pp. 914-930 ◽  
Author(s):  
P. Suriyachi ◽  
S. Kiatkamjornwong ◽  
P. Prasassarakich

Abstract Graft copolymer of glycidyl methacrylate and styrene onto natural rubber latex was synthesized by emulsion polymerization using cumene hydroperoxide and tetraethylene pentamine as a redox initiator. The effects of initiator and monomer concentration, reaction temperature and time on grafting efficiency and monomer conversion were investigated. The dynamic mechanical properties and morphology of grafted natural rubber were studied. The grafted natural rubber product could be used as a compatibilizer for natural rubber/PMMA blends. The mechanical properties such as tensile strength, elongation at break, tear strength, hardness, and impact energy were evaluated as a function of grafted natural rubber content. A good compatibility of natural rubber/PMMA blends was obtained at 5–10 phr of grafted natural rubber content. The fracture surface examined by scanning electron microscopy showed that the grafted natural rubber acted as an interfacial agent and gave a good adhesion between the two phases of the blend.


Molecules ◽  
2020 ◽  
Vol 25 (9) ◽  
pp. 2158
Author(s):  
Nanci Vanesa Ehman ◽  
Diana Ita-Nagy ◽  
Fernando Esteban Felissia ◽  
María Evangelina Vallejos ◽  
Isabel Quispe ◽  
...  

Bio-polyethylene (BioPE, derived from sugarcane), sugarcane bagasse pulp, and two compatibilizers (fossil and bio-based), were used to manufacture biocomposite filaments for 3D printing. Biocomposite filaments were manufactured and characterized in detail, including measurement of water absorption, mechanical properties, thermal stability and decomposition temperature (thermo-gravimetric analysis (TGA)). Differential scanning calorimetry (DSC) was performed to measure the glass transition temperature (Tg). Scanning electron microscopy (SEM) was applied to assess the fracture area of the filaments after mechanical testing. Increases of up to 10% in water absorption were measured for the samples with 40 wt% fibers and the fossil compatibilizer. The mechanical properties were improved by increasing the fraction of bagasse fibers from 0% to 20% and 40%. The suitability of the biocomposite filaments was tested for 3D printing, and some shapes were printed as demonstrators. Importantly, in a cradle-to-gate life cycle analysis of the biocomposites, we demonstrated that replacing fossil compatibilizer with a bio-based compatibilizer contributes to a reduction in CO2-eq emissions, and an increase in CO2 capture, achieving a CO2-eq storage of 2.12 kg CO2 eq/kg for the biocomposite containing 40% bagasse fibers and 6% bio-based compatibilizer.


2009 ◽  
Vol 25 (2) ◽  
pp. 113-128 ◽  
Author(s):  
P. Raju ◽  
V. Nandanan ◽  
Sunil K.N. Kutty

Mechanical properties and the thermal degradation characteristics of natural rubber compounds with calophyllum inophyllum oil were compared to that of the control compound containing naphthenic oil. The compounds containing calophyllum inophyllum oil showed improved tensile strength, tear strength, modulus, compression set, abrasion resistance and resilience. Cure time was higher than the naphthenic oil mixes. Thermal studies showed an increase of 8 °C in the temperature of initiation of degradation and an increase of 6 °C in temperature at which the peak rate of degradation occurred. The peak rate of degradation was comparable to the control mix containing naphthenic oil.


2018 ◽  
Vol 16 (36) ◽  
pp. 153-171
Author(s):  
Nahida J. H.

The present work studies the mechanical properties of SiO2 μPs, and NPs in St/PVA blends. The samples were prepared by casting method as PVA, St/PVA blends at different concentrations (30, 40, 50, and 60 %). DSC and TGA tests were carried out to the samples evolved. The result showed a single glass transition temperature (Tg) for all St /PVA blends that was attributed to the good miscibility of the blends involved. It was found that (Tg) decrease with starch ratio increase. It was seen that (PVA) of (Tg=105 oC); The glass transition temperature which was decrease with starch ratio that was attributed to glass transition relaxation process due to micro-Brownian motion of the main chain back bond. The endothermic peak at 200 oC was attributed to melting point of (PVA). Thermal properties of PVA; and St /PVA blends at different concentration (30, 40, 50, and 60 %) were evaluated by thermo gravimetric analysis (TGA). The analyses were carried out from 20 to 600 oC at 10 oC)/min heating rate in air oxygen atmosphere. The weight loss stages depended on polymer system. The starch addition causing shifting in the second degradation temperature to the higher temperature; which result in overlapping between the two main degradation steps, these result was attributed to the St/ PVA blend compatibility. The mechanical properties results showed a decrease in ultimate strength with starch ratio increase. The ultimate strength of (PVA) was (47 MPa), whereas the ultimate strength of 60 %St/PVA was (11 MPa) and for 30 %St/PVA was the highest ultimate strength of blends involved (26 MPa). SiO2μPs (753.7 nm), and NPs (263.1 nm) were added at different concentrations (1.5, 2, and 2.5 %). 1.5% SiO2μPs, and NPs of the best ultimate strength (69 MPa), (86 MPa) respectively then it was decreased by SiO2μPs, and NPs increase. Optical microscope of the samples involved was investigated. It was concluded the prepared samples were suggested to be used as packaging materials for agriculture application and its ultimate strength could be controlled by SiO2μPs, and NPs addition.


2000 ◽  
Vol 73 (5) ◽  
pp. 902-911 ◽  
Author(s):  
Amit K. Naskar ◽  
S. K. De ◽  
A. K. Bhowmick ◽  
P. K. Pramanik ◽  
R. Mukhopadhyay

Abstract Ground rubber tire (GRT) particles of different sizes were characterized and the effect of these particles in a natural rubber (NR) compound was studied. It is found that smaller particles contain less polymer, but have higher amounts of fillers and metals with respect to polymer. NR compound containing smaller GRT particles shows better physical properties, but poorer aging characteristics.


2005 ◽  
Vol 21 (3) ◽  
pp. 183-199
Author(s):  
G.K. Jana ◽  
C.K. Das

De-vulcanization of vulcanized elastomers represents a great challenge because of their three-dimensional network structure. Sulfur-cured gum natural rubbers containing three different sulfur/accelerator ratios were de-vulcanized by thio-acids. The process was carried out at 90 °C for 10 minutes in an open two-roll cracker-cum-mixing mill. Two concentrations of de-vulcanizing agent were tried in order to study the cleavage of the sulfidic bonds. The mechanical properties of the re-vulcanized rubber (like tensile strength, modulus, tear strength and elongation at break) were improved with increasing concentrations of de-vulcanizing agent, because the crosslink density increased. A decrease in scorch time and in optimum cure time and an increase in the state of cure were observed when vulcanized rubber was treated with high amounts of de-vulcanizing agent. The temperature of onset of degradation was also increased with increasing concentration of thio-acid. DMA analysis revealed that the storage modulus increased on re-vulcanization. From IR spectroscopy it was observed that oxidation of the main polymeric chains did not occur at the time of high temperature milling. Over 80% retention of the original mechanical properties (like tensile strength, modulus, tear strength and elongation at break) of the vulcanized natural rubber was achieved by this mechanochemical process.


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