Efficient thermo-oxidative reclamation of green tire rubber and silanized-silica/rubber interface characterization

Lightweight cement mortars containing end-of-life tire rubber (TR) as aggregate were prepared and characterized by rheological, thermal, mechanical, microstructural, and wetting tests. The mixtures were obtained after total replacement of the conventional sand aggregate with untreated TR with different grain sizes (0–2 mm and 2–4 mm) and distributions (25%, 32%, and 40% by weight). The mortars showed lower thermal conductivities (≈90%) with respect to the sand reference due to the differences in the conductivities of the two phases associated with the low density of the aggregates and, to a minor extent, to the lack of adhesion of tire to the cement paste (evidenced by microstructural detection). In this respect, a decrease of the thermal conductivities was observed with the increase of the TR weight percentage together with a decrease of fluidity of the fresh mixture and a decrease of the mechanical strengths. The addition of expanded perlite (P, 0–1 mm grain size) to the mixture allowed us to obtain mortars with an improvement of the mechanical strengths and negligible modification of the thermal properties. Moreover, in this case, a decrease of the thermal conductivities was observed with the increase of the P/TR dosage together with a decrease of fluidity and of the mechanical strengths. TR mortars showed discrete cracks after failure without separation of the two parts of the specimens, and similar results were observed in the case of the perlite/TR samples thanks to the rubber particles bridging the crack faces. The super-elastic properties of the specimens were also observed in the impact compression tests in which the best performances of the tire and P/TR composites were evidenced by a deep groove before complete failure. Moreover, these mortars showed very low water penetration through the surface and also through the bulk of the samples thanks to the hydrophobic nature of the end-of-life aggregate, which makes these environmentally sustainable materials suitable for indoor and outdoor elements.

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Improving Surface Imprinting Effect by Reducing Nonspecific Adsorption on Non-imprinted Polymer Films for 2,4-D Herbicide Sensors

Chemosensors ◽

10.3390/chemosensors9030043 ◽

2021 ◽

Vol 9 (3) ◽

pp. 43

Author(s):

Jin Chul Yang ◽

Suck Won Hong ◽

Jinyoung Park

Keyword(s):

Morphological Changes ◽

Unit Weight ◽

Dichlorophenoxyacetic Acid ◽

Surface Imprinting ◽

Imprinted Polymer ◽

Nonspecific Adsorption ◽

Chemical Surface ◽

Silane Modification ◽

Silanized Silica ◽

2,4 Dichlorophenoxyacetic Acid

Surface imprinting used for template recognition in nanocavities can be controlled and improved by surface morphological changes. Generally, the lithographic technique is used for surface patterning concerning sensing signal amplification in molecularly imprinted polymer (MIP) thin films. In this paper, we describe the effects of silanized silica molds on sensing the properties of MIP films. Porous imprinted poly(MAA–co–EGDMA) films were lithographically fabricated using silanized or non-treated normal silica replica molds to detect 2,4-dichlorophenoxyacetic acid (2,4-D) herbicide as the standard template. The silanized mold MIP film (st-MIP) (Δf = −1021 Hz) exhibited a better sensing response than the non-treated normal MIP (n-MIP) (Δf = −978 Hz) because the imprinting effects, which occurred via functional groups on the silica surface, could be reduced through silane modification. Particularly, two non-imprinted (NIP) films (st-NIP and n-NIP) exhibited significantly different sensing responses. The st-NIP (Δfst-NIP = −332 Hz) films exhibited lower Δf values than the n-NIP film (Δfn-NIP = −610 Hz) owing to the remarkably reduced functionality against nonspecific adsorption. This phenomenon led to different imprinting factor (IF) values for the two MIP films (IFst-MIP = 3.38 and IFn-MIP = 1.86), which was calculated from the adsorbed 2,4-D mass per poly(MAA–co–EGDMA) unit weight (i.e., QMIP/QNIP). Moreover, it was found that the st-MIP film had better selectivity than the n-MIP film based on the sensing response of analogous herbicide solutions. As a result, it was revealed that the patterned molds’ chemical surface modification, which controls the surface functionality of imprinted films during photopolymerization, plays a role in fabricating enhanced sensing properties in patterned MIP films.

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Evaluation of Measured and Predicted Resilient Modulus of Rubberized Stone Mastic Asphalt (SMA) Modified with Truck Tire Rubber Powder

Case Studies in Construction Materials ◽

10.1016/j.cscm.2021.e00633 ◽

2021 ◽

pp. e00633

Author(s):

Sajjad Noura ◽

Abdulnaser M. Al-Sabaeei ◽

Gailan Ismat Safaeldeen ◽

Ratnasamy Muniandy ◽

Alan Carter

Keyword(s):

Resilient Modulus ◽

Tire Rubber ◽

Rubber Powder ◽

Mastic Asphalt ◽

Truck Tire ◽

Stone Mastic Asphalt

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Altered gene expression in Chironomus riparius (insecta) in response to tire rubber and polystyrene microplastics

Environmental Pollution ◽

10.1016/j.envpol.2021.117462 ◽

2021 ◽

pp. 117462

Author(s):

Victor Carrasco-Navarro ◽

Ana-Belén Muñiz González ◽

Jouni Sorvari ◽

Jose-Luis Martínez Guitarte

Keyword(s):

Gene Expression ◽

Chironomus Riparius ◽

Tire Rubber ◽

Altered Gene Expression ◽

Altered Gene

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Hysteresis loss of ultra-large off-the-road tire rubber compounds based on operating conditions at mine sites

Proceedings of the Institution of Mechanical Engineers Part D Journal of Automobile Engineering ◽

10.1177/09544070211015525 ◽

2021 ◽

pp. 095440702110155

Author(s):

Shaosen Ma ◽

Guangping Huang ◽

Khaled Obaia ◽

Soon Won Moon ◽

Wei Victor Liu

Keyword(s):

Large Strain ◽

Tensile Tests ◽

Operating Conditions ◽

Hysteresis Loss ◽

Strain Rates ◽

Test Results ◽

Tire Rubber ◽

The Road ◽

Rubber Compounds ◽

Mine Sites

The objective of this study is to investigate the hysteresis loss of ultra-large off-the-road (OTR) tire rubber compounds based on typical operating conditions at mine sites. Cyclic tensile tests were conducted on tread and sidewall compounds at six strain levels ranging from 10% to 100%, eight strain rates from 10% to 500% s−1 and 14 rubber temperatures from −30°C to 100°C. The test results showed that a large strain level (e.g. 100%) increased the hysteresis loss of tire rubber compounds considerably. Hysteresis loss of tire rubber compounds increased with a rise of strain rates, and the increasing rates became greater at large strain levels (e.g. 100%). Moreover, a rise of rubber temperatures caused a decrease in hysteresis loss; however, the decrease became less significant when the rubber temperatures were above 10°C. Compared with tread compounds, sidewall compounds showed greater hysteresis loss values and more rapid increases in hysteresis loss with the rising strain rate.

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