What Are the Differences Between Virgin and Recycled Raw Material?
Among the numerous geosynthetics on the market, many are made from high molecular polymer materials, which have a significant advantage in terms of cost-performance. However, if the raw materials used are of poor quality, the products after molding are also difficult to be used for a long time. For geomembranes, there are significant differences in physical and chemical properties between new HDPE granules and recycled HDPE granules.
HDPE (high-density polyethylene) is processed into granular form and becomes one of the main raw materials of geomembranes. New polyethylene granules have pure composition, uniform texture and appear as white semi-transparent elliptical granules.
Permeability Resistance:
The permeability coefficient is one of the most important performance indicators of geomembrane. The new high-density polyethylene raw material has a consistent internal density and is further processed to form HDPE geomembrane, which retains the basic characteristics of the former and also has excellent density consistency—the internal molecular arrangement is uniform and the gaps are small. Therefore, the permeability coefficient is extremely low.
The permeability coefficient of HDPE geomembrane produced with new material should be ≤1.0x10-13 cm/s, which can be much lower than the national standard (GB/T 17643-2025) and should also meet the GRI-gm13 2016 test standard. Recycled HDPE raw material, due to the presence of impurities and uneven density, cannot meet the design life of any large-scale project, such as landfill sites, tailings ponds, biogas pools, water conservancy projects...
Mechanical Properties:
Since geomembranes are mostly installed on the ground, the tensile strength, puncture strength, tear strength and maximum elongation at break of the membrane body must meet the actual engineering requirements. New high-density polyethylene itself has excellent extensibility and excellent resistance to tensile force, capable of withstanding the pressure of different substrates, backfill soil and gas & liquid.
The new raw material HDPE geomembrane can meet all the mechanical indicators under all standards, with the maximum elongation rate easily reaching 700%. The high-density polyethylene content in recycled raw materials cannot reach the specified 97% or above, so recycled geomembrane cannot pass most test standards. The possible structural failure in high-pressure environments will lead to engineering accidents.
Physical Properties:
In the GRI-gm13 and GB/T 17643 standards, there are clear ranges for the thickness and density tolerances of the geomembrane. New HDPE raw materials can achieve stable tolerance control during the process, ensuring product quality and pass rate. Recycled HDPE raw materials, due to their complex composition, complex thermal melting treatment and significant damage to production equipment, have a far less smooth and clean surface than new HDPE geomembranes after molding. Besides, the thickness is also unable to be consistent.
Chemical Properties:
The anti-aging, antioxidant and anti-ultraviolet indicators of the new HDPE raw material are fully capable of meeting the requirements of hazardous waste treatment projects and satisfying the design for the permanent service life of major environmental protection projects. However, the recycled raw material cannot completely resist the chemical reactions with various leachates for its addition of various other plastic waste materials. Once a hazardous waste leakage occurs, it will cause significant environmental pollution.
Zhonglong's HDPE geomembrane are manufactured from virgin HDPE raw material to meet the demand of high-standards engineering projects.
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Sichuan Zhonglong Environmental Protection Co., Ltd.
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