Study On Aging Induced Properties Evolution Of PE Drip Irrigation Tape And Its Modification Recycling

Drip irrigation tape is an important part in drip irrigation system, which accounts a large proportion of investment in drip irrigation system because it’s heavy usage. Regeneration drip tape made up of recycled waste drip tape is usually marked by poor performance. This may prevent the recycling of drip tape and the promotion of drip irrigation system. The research of modified recycling to waste PE is favorable to resources utilization, and also to lower the cost of the product and improve the performance of regeneration drip tape.In this paper, mechanical properties evolution of as-received drip tape before and after aging during farm irrigation and artificial accelerated aging by xenon lamp aging chamber were studied. The correlation between the two different aging methods was investigated. Then the microstructure and composition changes of PE drip tape before and after aging were researched. After that, experiment was conducted to study the effect of modifiers on the injection moldability of waste PE material and the mechanical performance of recycled material. In the end, mechanical performance and aging-resistance of the modified recycled drip tape were verified. The main contents and results are as follows:(1)The maximum axial tensile strength and elongation of the as-received drip tape were increased slowly with the early passing of irrigation time, reaching maximum at the time of 7 months of irrigation. After that, the maximum axial tensile strength and elongation decreased. The maximum axial tensile strength went back to the same level of as-received drip tape when as-received drip tape was irrigating for almost one year. Nature rebound resilience maintained a downward trend with a decreasing drop speed.(2) With the increase of radiation intensity and accumulation of radiation, the maximum axial tensile strength and elongation of the as-received drip tape first increased, and then decreased in the artificial accelerated ageing test, while nature rebound resilience has been declining. When the radiation intensity was constant, the maximum axial tensile strength and elongation of as-received drip tape first decreased, and then increased with the rise of aging temperature; nature rebound resilience occurred repeated fluctuations.(3)The main components of PE drip tape have not changed after 7 months of irrigation, but the content of small molecules and the degree of crystallinity have increased. Crosslinks and crosslinked structures were not found on the surface of aged drip tape; the accumulation of irradiation could eliminate the wrinkles to some extent which occurred on drip tape’s surface during the production process.(4) Dicumyl Peroxide(DCP) has adverse impact on the injection moldability of waste PE material while Ethylene-vinyl Acetate Copolymer(EVA) has positive effects on it. EVA could promote the elastic property of recycled waste PE material and DCP could promote the maximum axial tensile strength of recycled waste PE material but has adverse impact on the elastic property. With the 6%EVA+0.4%DCP modifier formulation, the maximum axial tensile strength, elongation and nature rebound resilience of recycled waste PE material could be improved at the same time.(5) The mechanical performance of the modified recycled drip tape was close to that of the as-received drip tape, and the aging-resistance of modified recycled drip tape was better than unmodified recycled drip tape which validated by artificial accelerated ageing test.