scholarly journals Investigation of Different Types of Biochar on the Thermal Stability and Fire Retardance of Ethylene-Vinyl Acetate Copolymers

Polymers ◽  
2021 ◽  
Vol 13 (8) ◽  
pp. 1256
Author(s):  
Samuele Matta ◽  
Mattia Bartoli ◽  
Alberto Frache ◽  
Giulio Malucelli

In this work, three biochars, deriving from soft wood, oil seed rape, and rice husk and differing as far as the ash content is considered (2.3, 23.4, and 47.8 wt.%, respectively), were compounded in an ethylene vinyl acetate copolymer (vinyl acetate content: 19 wt.%), using a co-rotating twin-screw extruder; three loadings for each biochar were selected, namely 15, 20, and 40 wt.%. The thermal and mechanical properties were thoroughly investigated, as well as the flame retardance of the resulting compounds. In particular, biochar, irrespective of the type, slowed down the crystallization of the copolymer: this effect increased with increasing the filler loading. Besides, despite a very limited effect in flammability tests, the incorporation of biochar at increasing loadings turned out to enhance the forced-combustion behavior of the compounds, as revealed by the remarkable decrease of peak of heat release rate and of total heat release, notwithstanding a significant increase of the residues at the end of the tests. Finally, increasing the biochar loadings promoted an increase of the stiffness of the resulting compounds, as well as a decrease of their ductility with respect to unfilled ethylene vinyl acetate (EVA), without impacting too much on the overall mechanical behavior of the copolymer. The obtained results seem to indicate that biochar may represent a possible low environmental impact alternative to the already used flame retardants for EVA, providing a good compromise between enhanced fire resistance and acceptable mechanical properties.

10.6036/10031 ◽  
2021 ◽  
Vol 96 (3) ◽  
pp. 302-308
Author(s):  
XIAN WANG ◽  
JUNYI DAI ◽  
TIANQING XING ◽  
JINLONG ZHUO

Ethylene-vinyl acetate copolymer (EVA) is widely used due to its good processability, low density, and low temperature resistance. However, it burns easily and has several disadvantages, such as a high heat release rate and melt dripping, and it emits large amounts of smog and toxic harmful gases. These disadvantages greatly limit the application of EVA in the wire and cable field. In this study, a series of carbon fiber (CF)/9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO)/EVA composites are prepared through melt compounding to improve the flame retardancy and mechanical properties of EVA. The flame retardancy, thermal stability, and mechanical properties of the composites are studied through microscale combustion calorimeter experiments, cone calorimeter tests, thermogravimetric analysis, digital camera, and tensile measurements. Results indicate that among the six samples, the EVA-5 composite with 4.0 wt% CF, 16.0 wt% DOPO, and 80 wt% EVA has the highest limiting oxygen index value (25.1%) and reaches the V-1 level of the Underwriters Laboratory-94 test. Compare with that of pure EVA, the peak heat release rate of the EVA-5 composite has reduced by 30.2% and 47.7%. In addition, the total heat release of EVA-5 reduces by 17.0% and 34.8% relative to that of pure EVA. Data of thermogravimetric analysis show that the thermal stability of CF/DOPO/EVA improves with the increase in CF loading. Moreover, the tensile strength and elongation-at-break values of EVA-5 are 14.30 MPa and 1142.87%, respectively, indicating that this material can maintain good mechanical properties. CF not only enhances the tensile properties of EVA but also acts as a skeleton during burning. This action could increase the strength of the carbon layer and enhance the flame-retardant effect of DOPO. CF and DOPO have an enhanced synergistic effect that could improve the flame retardancy, thermal stability, and mechanical properties of EVA composites. This work provides a theoretical basis for the preparation and production of CF/DOPO/EVA composites with good comprehensive performance. Keywords: thylene-vinyl acetate copolymer; 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide; carbon fiber; flame retardant; synergistic effects


2014 ◽  
Vol 936 ◽  
pp. 17-22
Author(s):  
Xin Li ◽  
Yu Xiang Ou

Polypropylene (PP) and ethylene vinyl acetate copolymer (EVA) were treated with intumescent flame retardants containing caged bicyclic phosphates. The behavior of thermal degradation of the flame-retarded PP and EVA were studied by TG, DSC, and the FTIR spectra of PP’s residues at different temperature were recorded. In addition, the possible thermal degradation and char formation mechanisms were analyzed and discussed.


Materials ◽  
2020 ◽  
Vol 13 (20) ◽  
pp. 4669
Author(s):  
Łukasz Zedler ◽  
Paulina Burger ◽  
Shifeng Wang ◽  
Krzysztof Formela

Ground tire rubber (GTR) was reclaimed and modified with 10 phr of ethylene-vinyl acetate copolymer via low-temperature extrusion process. Processing, physico-mechanical properties, volatile organic compounds emission, and recycling possibility were investigated. In order to better understand the impact of used modifiers, their efficiency was compared with trans-polyoctenamer, which is an additive that is commercially dedicated to waste rubber recycling. The results showed that a relatively small amount of ethylene-vinyl acetate copolymer improves the mechanical properties of modified reclaimed GTR and also allows further recycling by multiple processing without the deterioration of performance after three cycles.


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