Tham khảo tài liệu 'recycling of plastic materials part 10', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | 148 The Use of Recyclable Plastics in Motor Vehicles Ballistic test All test samples showed a ductile fracture. It is however difficult to compare the values determined for injection-moulded test specimens with those exhibited by the original tank material and those specified by the quality order since the test specimens were only 3 mm thick compared with the average thickness of a tank which is between 5 and 8 mm. Degree of crystallinity The degree of crystallinity of both the fluorinated and unfluorinated materials both after one regrinding and one remoulding lay within the provisions of the quality order. Melting temperature The remelting temperature of fluorinated and unfluorinated materials both after regrinding and after remoulding lay below the temperature range stipulated by the quality order. Flow index No difference could be detected between fluorinated and unfluorinated samples evaluated by a spiral flow mould test. The recycling of material from used fuel tanks Parallel investigations were carried out to establish how much fuel the tank material absorbs and the time involved for the fuel to migrate from the material when no longer exposed to fuel. At a room temperature samples punched from the original fluorinated tank achieved constant weight with weight increases in the range . Since material recycling cannot take place without elimination of the fuel drying tests were carried out under a range of conditions. It was established that temperatures exceeding 100oC were necessary to eliminate all fuel. The material used for the investigation was obtained from Volkswagen Golf and Passat vehicles which have employed plastic fuel tanks for some 10 years. The time required for tank removal cleaning and elimination of tank components made either of metal or a plastic other than HDPE averaged some 5 min 30 sec. At a labour cost of DM 45 h this implies some DM for recovery of a fuel tank yielding kg of HDPE with at a price of about DM kg for
