Thermomechanical and Structural Analysis of Biocomposites and Gamma Irradiation and Photoaging on Mechanical and Viscoelastic Properties
Babacar Niang,
Abdoulaye Bouya Diop,
Abdou Karim Farota,
Nicola Schiavone,
Haroutioun Askanian,
Vincent Verney,
Abdoul Karim Mbodji,
Malick Wade,
Diène Ndiaye,
Bouya Diop
Issue:
Volume 11, Issue 3, September 2022
Pages:
50-59
Received:
26 February 2022
Accepted:
25 April 2022
Published:
26 July 2022
DOI:
10.11648/j.am.20221103.11
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Abstract: The replacement of petrochemical fibres with natural fibres for reinforcing polyvinyl chloride matrix biomaterials is currently being researched and applied in the technical and technological fields. Natural fibres offer environmental advantages combined with economic advantages related to comparatively lower cost and lower energy consumption. it is in this context that typha stem fibres extracted from the typha plant found in south-saharan Africa are used in this study for the manufacture of biocomposites. The objective is to evaluate the thermogravimetric (TG/DTG) and viscoelastic behaviour of polyolefin matrix biocomposites reinforced with relatively high volume fractions, 25, 35 and 45%, of typha stem powder. The incorporation of typha stem powder slightly reduces the thermal stability of the biomaterials by decreasing the thermal degradation onset temperature and the DTG peak temperature compared to pure matrices. The limit for the practical application of these composites could be set at 270°C, before the onset of major weight loss. Monitoring of the different materials by rheological measurements during photoaging allowed to understand the mechanisms of photodegradation. The shear thinnig behaviour observed on the complex viscosity points to possible small changes at the molecular level. Photochemical degradation over the photo-aging cycles resulted in cut-off and recombination phenomena. Dynamic storage moduli (G') and loss moduli (G'') tend to increase with the proportion of typha powder. The dynamic storage modulus (G') and loss modulus (G'') tend to increase with the proportion of typha powder. We observed a rheofluidic behaviour by shearing of the melt. The dynamic storage (G') and loss (G'') moduli tend to increase with the proportion of typha powder. From a thermal and rheological point of view, HDPE-based biocomposites show interesting properties for use in applications. The influence of gamma irradiation leads to a competition between two mechanisms (chain breaks and recombination) of photooxidation that take place together within the material. Mechanical properties such as tensile and flexural strength are improved with increasing gamma radiation dose up to 75 kGy.
Abstract: The replacement of petrochemical fibres with natural fibres for reinforcing polyvinyl chloride matrix biomaterials is currently being researched and applied in the technical and technological fields. Natural fibres offer environmental advantages combined with economic advantages related to comparatively lower cost and lower energy consumption. it i...
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Physico-Chemical Characteristics and Study Valorization Ways of the Cotton Sector Waste in Benin to Biobased Building Materials
Abdou Raimi Alakouko,
Guy Clarence Semassou,
Roger Houechene Ahouansou,
Clotide Guidi
Issue:
Volume 11, Issue 3, September 2022
Pages:
60-68
Received:
5 July 2022
Accepted:
22 July 2022
Published:
29 July 2022
DOI:
10.11648/j.am.20221103.12
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Abstract: The economic importance of the cotton sector in West African countries has led to the development of this sector, which now generates a large quantity of waste. The objective of the present study is to investigate the possibilities of valorization of the by-products of the cotton sector into construction materials. The investigations near the actors of the cotton sector have made it possible to trace the itinerary of the cotton and to bring out fifteen (15) by-products from industries of which five (5) in the ginning mills, six (6) in the crushing mills and four (4) in the textile mills. The most important ones are cotton seed hulls, ginning clods and glue wastes which represent respectively 16%, 1.45% and 0.84% of the annual cotton production. Some physico-chemical characteristics allowed to evaluate the use of these by-products in construction materials. The higher calorific value and the protein content, which are respectively 19,536 J/g and 1.6%, make the hulls an alternative fuel and a feed for livestock. This by-product is fully utilized. As for the ginning clods, they are in the form of fibers. Due to their low apparent density of 25 kg/m3, it is possible to use these clods in the manufacture of light construction materials. The glue wastes also contain 18% of starch, which makes it possible to consider its use in the production of thermal insulation panels inside the building. Although this study allows us to identify possible ways to valorize the by-products of the cotton sector, it remains to find the appropriate methods of their implementation.
Abstract: The economic importance of the cotton sector in West African countries has led to the development of this sector, which now generates a large quantity of waste. The objective of the present study is to investigate the possibilities of valorization of the by-products of the cotton sector into construction materials. The investigations near the actor...
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Effect of Secondary Graphitization Expansion on Micro-shrinkage Porosity of Ductile Iron
Shuying Chen,
Qingchun Li,
Jiajian Song,
Ming Sun,
Haiqing Sun,
Guowei Chang
Issue:
Volume 11, Issue 3, September 2022
Pages:
69-76
Received:
28 June 2022
Accepted:
18 July 2022
Published:
9 August 2022
DOI:
10.11648/j.am.20221103.13
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Abstract: Secondary graphitization annealing is often used to obtain 100% ferrite matrix in the production of ductile iron. The volume expansion of pearlite will occur during secondary graphitization annealing. So far, whether this expansion can affect the micro-shrinkage porosity between the austenite rings surrounding the graphite nodule during solidification has not attracted people's attention, while micro-shrinkage porosity is one of the primary factors affecting the impact toughness of ductile iron at ultra-low temperature. Aiming at the problem of whether the secondary graphitization of ductile iron affects the micro-shrinkage porosity, the secondary graphitization annealing of pearlitic ductile iron is carried out, and the effect of secondary graphitization expansion on micro-shrinkage porosity was studied. The metallographic microstructures and micro-shrinkage porosity are observed by Axiovert200MAT metallographic microscope and MLA250 (FEIQuanta) scanning electron microscope. The maximum length of micro-shrinkage porosity is measured by Nano Measurer 1.2 and the maximum area is measured by Photoshop software. The results show that the volume expansion rates of ductile iron and gray cast iron after secondary graphitization annealing are about 1.2% and 1.4%, respectively. After secondary graphitization annealing, the size and quantity of micro-shrinkage porosity of ductile iron decrease. It indicates that the expansion after secondary graphitization of cast iron will help to repaire micro-shrinkage porosity.
Abstract: Secondary graphitization annealing is often used to obtain 100% ferrite matrix in the production of ductile iron. The volume expansion of pearlite will occur during secondary graphitization annealing. So far, whether this expansion can affect the micro-shrinkage porosity between the austenite rings surrounding the graphite nodule during solidificat...
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