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Chemical property and characteristics of polymer
Published in S. Thirumalai Kumaran, Tae Jo Ko, S. Suresh Kumar, Temel Varol, Materials for Lightweight Constructions, 2023
A. Sofi, Joshua Jeffrey, Abhimanyu Singh Rathor
Nanoparticles are often defined as having at least one dimension in the range of 1–100 nm and all other dimensions more than 100 nm. Nanoparticles are described as those with three nano dimensions, nanofibers have two, and nanoplates have one. The stiffest known natural substance is graphite, which has a Young’s modulus of about 1,000 MPa. It’s a layered mineral made up of graphene layers piled on top of one other. The graphene layers are very strong and rigid, making them perfect for use as nanoplates. Expandable graphite is most commonly used in polymers nowadays as an intumescent fire-retardant ingredient [49]. These graphite compounds are designed to stay chemically stable during the polymer manufacturing process and only exfoliate if they catch fire.
Intumescent FRs (IFRs)
Published in Asim Kumar Roy Choudhury, Flame Retardants for Textile Materials, 2020
Expandable graphite (EG) represents another class of inorganic intumescent systems. EG swells during combustion to form a char layer, which prevents the access of oxygen to the combustion zone. Expandable graphite is one of the intumescent flame retardant additives that is produced by intercalation of sulfuric acid into graphite in the presence of a strong oxidizing agent. At elevated temperatures, expandable graphite decomposes with an emission of volatile products. This causes the formation of a foamed char layer, which is a physical barrier that reduces heat and mass transfer between burning materials and the environment. EG has been used advantageously in PU coatings to develop fire protective coating for polymeric substrates.
Bitumen and flat roofing materials
Published in Arthur Lyons, Materials for Architects and Builders, 2019
Reinforced bitumen membrane (RBM) roofs consist of two or more layers of bitumen sheets bonded together with self-adhesive or hot bitumen. The individual bitumen sheets are manufactured from a base carrier of either glass or fibre matting that is impregnated and coated with bitumen. Some products also have an applied adhesive backing and/or a surface protective finish. An enhanced fire performance can be gained by the incorporation of expandable graphite crystals within the base layer.
Experimental Study on Feasibility of EG Gel Optimizing Mine Fire Control Technology
Published in Combustion Science and Technology, 2023
Yingxin Zhang, Rijun Li, Yifei Wang, Xuan Wu, Jiawei Wang, Lu Tang, Kang Yang
Expandable graphite is expanded by heat, forming a high rate, and light quality “worm” solid graphite. In the air leakage environment of goaf, expanded graphite is easy to drift with the wind, which is not conducive to sealing the cracks in the fire area. To ensure the smooth injection of expandable graphite into the fire zone and accurate filling of the fire zone fissures. So, liquid materials with a certain consistency are required to carry expandable graphite. At the same time, the expanded graphite worm should be cemented effectively to form a block collection sufficient to resist the strength of mine air leakage. Therefore, the experiment uses different amounts of polyvinyl alcohol colloid. In order to study its ability to bond expand graphite. The results of the analysis are shown in Figures 3 and 4.
Experimental study on thermal management and performance improvement of solar PV panel cooling using form stable phase change material
Published in Energy Sources, Part A: Recovery, Utilization, and Environmental Effects, 2023
Senthil Kumar Marudaipillai, Balasubramanian Karuppudayar Ramaraj, Ravi Kumar Kottala, Maheswari Lakshmanan
The cost involved in the PV-composite PCM systems are (i) PCM material cost; (ii) cost of the expandable graphite material; (iii) cost of aluminum heat sink; and (iv) fabrication cost of the container. Typically, the cost of the material majorly depends on the purity of the material and bulk quantity of material to be purchased (Hasan et al. 2014). These material costs are further divided into the cost of materials purchased in kilograms for the experimental setup and cost of the materials when purchased in larger quantities. The cost of PCM (PEG1000-99.99% high purity) and expanded graphite (EG) for the experimentation is Rs. 3652 per kilogram (procured from Alfa Aesar) and Rs. 600 per kilogram respectively, when procured in smaller quantities. However, this cost may reduce to Rs. 115 per kilogram and Rs. 51 per kilogram of PCM and EG, respectively, when purchased in large quantities with a minimum 1 tonne which is supplied from local suppliers. Due to the variable price of the material, it is necessary to study the economic feasibility of both the passive techniques for single system and mass-produced PV/composite PCM system. Total 850 g of composite PCM is used for experimentation, out of all, 85%, i.e. 723 g of PEG1000 and 127 g of EG is used for the preparation of composite PCM.
Thermal and morphological study of paraffin/SEBS/expanded graphite composite phase change material for thermal energy storage
Published in Energy Sources, Part A: Recovery, Utilization, and Environmental Effects, 2022
Jaspreet Singh Aulakh, Deepika P. Joshi
Expandable graphite has been prepared at room temperature by mixing 16 ml of H2SO4 (used as an intercalant) (98%) and 1.5 ml H2O2 (30%) (as an oxidant) with 6 gm graphite flakes. The mixture has been stirred for 90 min over a magnetic stirrer. Then the prepared mixture has been left for around 24 hours to complete the intercalation process. The resulting mixture has been filtered and washed repeatedly with distilled water to maintain the pH in the range between 6 and 7. Finally, the prepared mixture was dried at 60°C for 48 hours to obtain the intercalated graphite or expandable graphite. Since graphite is a good absorber of microwave, therefore intercalated graphite has been expanded in a microwave oven. The intercalated graphite has been placed directly into a microwave oven operated at 100 W for 60 s to obtain EG. This technique is simple, safe, and requires less energy than heat treatment by a muffle furnace.