title: Effect of high energy electron beam (10MeV) on specific heat capacity of low-density polyethylene/hydroxyapatite nano-composite.
abstract: In the present work, thermal properties of low density polyethylene (LDPE) and its nano composites are investigated. For this purpose LDPE reinforced with different weight percents of hydroxyapatite (HAP) powder which was synthesized via hydrolysis method are produced. The samples were irradiated with 10MeV electron beam at doses of 75 to 250kGy. Specific heat capacity measurement have been carried out at different temperatures, i.e. 25, 50, 75 and 100°C using modulated temperature differential scanning calorimetry (MTDSC) apparatus and the effect of three parameters include of temperature, irradiation dose and the amount of HAP nano particles as additives on the specific heat capacity of PE/HAP have been investigated precisely. The MTDSC results indicate that the specific heat capacity have decreased by addition of nano sized HAP as reinforcement for LDPE. On the other hand, the effect of radiation dose is reduction in the specific heat capacity in all materials including LDPE and its nano composites. The HAP nano particles along with cross-link junctions due to radiation restrain the movement of the polymer chains in the vicinity of each particle and improve the immobility of polymer chains and consequently lead to reduction in specific heat capacity. Also, the obtained results confirm that the radiation effect on the specific heat capacity is more efficient than the reinforcing effect of nano-sized hydroxyapatite.
authors.affiliation: Health Physics and Radiation Dosimetry Research Laboratory, Department of Energy Engineering and Physics, Amirkabir University of Technology, Tehran, Iran. Electronic address: zhr_soltani@yahoo.com.
authors.forename: Z
authors.initials: Z
authors.lastname: Soltani
authors.affiliation: Radiation Application Research School, Nuclear Science & Technology Research Institute, Tehran, Iran.
authors.forename: F
authors.initials: F
authors.lastname: Ziaie
authors.affiliation: Polymer Group, Golestan University, Golestan, Iran.
authors.forename: M
authors.initials: M
authors.lastname: Ghaffari
authors.affiliation: Radiation Application Research School, Nuclear Science & Technology Research Institute, Tehran, Iran.
authors.forename: A M
authors.initials: AM
authors.lastname: Beigzadeh
mesh_terms: D003432:Cross-Linking Reagents / Q000737:chemistry; D017886:Durapatite / Q000737:chemistry*; D004583:Electrons; D006358:Hot Temperature; D008970:Molecular Weight; D053761:Nanocomposites / Q000737:chemistry*; D020959:Polyethylene / Q000737:chemistry*
chemical_list: D003432:Cross-Linking Reagents; D020959:Polyethylene; D017886:Durapatite
keywords: Cross-link junctions; Electron beam; Hydroxyapatite; LDPE; Nano composite; Specific heat capacity