Grafting and reactive extrusion technologies for compatibilization of ground tyre rubber composites: Compounding, properties, and applications

Phiri, Mapoloko Mpho; Phiri, Mohau Justice; Formela, Krzysztof; Wang, Shifeng; Hlangothi, Shanganyane Percy

doi:10.1016/j.jclepro.2022.133084

Cited by 20 publications

(14 citation statements)

References 149 publications

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“…This powder is subsequently used as raw material or additive in other products of interest for diverse applications. In particular, the elastomeric properties of GTR make it an interesting filler agent to improve the mechanical properties of a wide range of materials including thermoplastics, thermosets, virgin or composite rubbers, concrete, bitumen or asphalt [1][2][3][5][6][7][8][9]. For example, the introduction of GTR fillers in polystyrene (PS), which is investigated in this work, can produce a composite material with improved stress cracking resistance and impact strength, with respect to the brittle pure PS matrix, and with reduced material costs.…”

Section: Introductionmentioning

confidence: 99%

“…However, the different structures of the two phases (i.e., the PS matrix and GTR, GTR having the form of a 3D crosslinked network) present a challenge in terms of their compatibility and the resulting poor mechanical properties of the final blend. Accordingly, several compatibilization strategies can be envisioned, such as devulcanization and reclamation or surface activation [2,3,5,6,10,11]. In this work, a chemical surface activation strategy in the form of in situ cross-linking by grafting polymerization, which is among the most prominent GTR surface modification techniques [6], is employed to produce PS-GTR composites.…”

Section: Introductionmentioning

confidence: 99%

“…Accordingly, several compatibilization strategies can be envisioned, such as devulcanization and reclamation or surface activation [2,3,5,6,10,11]. In this work, a chemical surface activation strategy in the form of in situ cross-linking by grafting polymerization, which is among the most prominent GTR surface modification techniques [6], is employed to produce PS-GTR composites. More specifically, PS is directly grafted onto the surface of GTR particles that are present during the radical polymerization of styrene.…”

Section: Introductionmentioning

confidence: 99%

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A Comprehensive Study on the Styrene–GTR Radical Graft Polymerization: Combination of an Experimental Approach, on Different Scales, with Machine Learning Modeling

et al. 2023

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The study of the styrene–Ground Tire Rubber (GTR) graft radical polymerization is particularly challenging due to the complexity of the underlying kinetic mechanisms and nature of GTR. In this work, an experimental study on two scales (∼10 mL and ∼100 mL) and a machine learning (ML) modeling approach are combined to establish a quantitative relationship between operating conditions and styrene conversion. The two-scale experimental approach enables to verify the impact of upscaling on thermal and mixing effects that are particularly important in this heterogeneous system, as also evidenced in previous works. The adopted experimental setups are designed in view of multiple data production, while paying specific attention in data reliability by eliminating the uncertainty related to sampling for analyses. At the same time, all the potential sources of uncertainty, such as the mass loss along the different steps of the process and the precision of the experimental equipment, are also carefully identified and monitored. The experimental results on both scales validate previously observed effects of GTR, benzoyl peroxide initiator and temperature on styrene conversion but, at the same time, reveal the need of an efficient design of the experimental procedure in terms of mixing and of monitoring uncertainties. Subsequently, the most reliable experimental data (i.e., 69 data from the 10 mL system) are used for the screening of a series of diverse supervised-learning regression ML models and the optimization of the hyperparameters of the best-performing ones. These are gradient boosting, multilayer perceptrons and random forest with, respectively, a test R2 of 0.91 ± 0.04, 0.90 ± 0.04 and 0.89 ± 0.05. Finally, the effect of additional parameters, such as the scaling method, the number of folds and the random partitioning of data in the train/test splits, as well as the integration of the experimental uncertainties in the learning procedure, are exploited as means to improve the performance of the developed models.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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A Comprehensive Study on the Styrene–GTR Radical Graft Polymerization: Combination of an Experimental Approach, on Different Scales, with Machine Learning Modeling

et al. 2023

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“…The GTR in these composites has been found to improve impact strength and reduce crack propagation. However, many research works confirmed that the hydrophobic and cross-linked nature of GTR made it incompatible with plastic matrixes, which induced very poor mechanical properties of composite materials, therefore necessitating compatibilization to help improve its interaction adhesion with matrixes [ 30 , 31 , 32 ]. For instance, Sonnier et al found that dicumyl peroxide (DCP) could enhance the compatibility of GTR and high-density polyethylene (HDPE), and then the better mechanical properties, elongation at break and impact energy of the composites were obtained [ 33 ].…”

Section: Introductionmentioning

confidence: 99%

Mechanical Properties, Crystallization Behaviors and Phase Morphologies of PLA/GTR Blends by Reactive Compatibilization

Shen

Lin

et al. 2022

Materials

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Different ratios of Polylactic acid/Ground tire rubber (PLA/GTR) were prepared by melt blending and adding dicumyl peroxide (DCP) as a reactive compatibilizer. The compatibilizer could initiate a reaction between PLA and GTR to increase the compatibility and interfacial adhesion of the two phases, as indicated by Fourier transform infrared (FTIR) spectrometry and scanning electron microscopy (SEM). Adding the compatibilizer significantly improved the impact strength of the PLA/GTR blends without compromising the tensile strength. The elongation at the break and notched Izod impact strength of the blend increased by 61.8% and 150%, respectively, but there was only a 4.1% decline in tensile strength compared with the neat PLA. The plastic deformation on the impact fractured surface showed that the improvement of toughness could be attributed to the compatibilization initiated by DCP. Therefore, the improvement of the interfacial adhesion and compatibility of the two phases induced a brittle–ductile transition that occurred in the failure of blends. Moreover, the crystallinity of blends reached 40.5% without a further annealing treatment, which was nearly 24 times of the neat PLA, and the crystallization rate was enhanced simultaneously. These exciting findings suggest that compatibilization can provide a promising avenue for fabricating GTR-toughened PLA blends with balanced stiffness–toughness.

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“…Modifying the ground tire rubber to make it compatible with the matrix is a more versatile method. The most well-known technical solutions for its implementation are chemical modification and reactive extrusion [12]. Chemical modification of the rubber crumb surface can be carried out by bitumen itself, if an efficient heat supply is ensured by the microwave treatment [13].…”

Section: Introductionmentioning

confidence: 99%

Production of a nanostructured bitumen modifier in the reprocessing of automobile tires

Красновских¹,

Chudinov²,

Sliusar³

et al. 2022

Nanobuild

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Introduction. Polymer-bitumen binders are innovative nano-binders for asphalt concrete pavement. Introduction of a polymer modifier improves the characteristics of bitumen and asphalt concrete. The use of waste tires rubber for bitumen modification is considered to be an environmentally friendly solution, but it is limited due to the poor cosite of rubber with bitumen. Various methods based on activation of the rubber surface, dispersion of rubber to nanosized particles, and thermochemical transformations of rubber into individual organic compounds are known to overcome this limitation. Methods and materials. The method of joint pyrolysis of rubber with oxygen-containing oil under pressure is proposed to be used for converting it into a nanostructural bitumen modifier. The resulting product is studied by the methods of thermogravimetry, NMR-spectroscopy, chromatomasspectrometry, scanning electron microscopy and solubility in toluene. Results and discussion. It has been established that during joint pyrolysis rubber undergoes devulcanization, cracking and dispersion to nanosized particles, and as a result the product becomes compatible with bitumen. Thermochemical reprocessing of waste automobile tires can be considered to be a promising method for the production of a nanostructured bitumen modifier. Conclusion. The use of thermochemical pressure treatment of waste tire rubber in the presence of oxygen-containing oil makes it possible to obtain a nanostructured product compatible with bitumen for further use of the resulting modifier in the production of asphalt concrete.

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Grafting and reactive extrusion technologies for compatibilization of ground tyre rubber composites: Compounding, properties, and applications

Cited by 20 publications

References 149 publications

A Comprehensive Study on the Styrene–GTR Radical Graft Polymerization: Combination of an Experimental Approach, on Different Scales, with Machine Learning Modeling

A Comprehensive Study on the Styrene–GTR Radical Graft Polymerization: Combination of an Experimental Approach, on Different Scales, with Machine Learning Modeling

Mechanical Properties, Crystallization Behaviors and Phase Morphologies of PLA/GTR Blends by Reactive Compatibilization

Production of a nanostructured bitumen modifier in the reprocessing of automobile tires

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