Avoid Failure, Improve Performance, and Reduce Cost : Surface Modify Your Geosynthetics with Fluoro-Seal Reactive Gas Treatments
Fluoro-Seal treatments with elemental reactive gas create chemical change in the exposed surface molecules of thermoplastics, including geosynthetics. Reactive gas molecules bond to and chemically modify all exposed surfaces. The treatment has been used for many years to increase hydrocarbon barrier properties and enhance adhesive bonding to coatings, sealants, and epoxies.
Bond Geosynthetics to Almost Anything And Increase Permeation Resistance As Well As • Increase Chemical Resistance • Increase Resistance to Surface Oxidation • Increase Resistance to Stress Crack Initiation • Reduce Depletion of Stabilizers
Surface Modification Improves Performance and Long Term Durability of Containment Systems Fluoro-Seal Treatments • Reduce potential for future failure • Lower life-cycle costs • Permit new applications of lower cost materials • Reduce liability by reducing failure frequencies • Reduce liability by using “best-available-technology”
For example, polyethylene liners have traditionally been joined with heat seaming and mechanical attachment. Use of adhesives and coatings have been out of the question due to poor adhesion. But good quality “structural” adhesion is now possible by chemically changing the surface of geomembranes through Fluoro-Seal reactive gas initiated surface modification. The process provides a surface treatment similar to corona, plasma, or flame treatments, while going deeper into the material with a much more effective and long term change of surface chemistry. Surface Modified Geosynthetics Permit High Strength Adhesive Assembly
Reliable “structural” adhesive assembly through Fluoro-Seal surface modification means 1) Better installation and repair opportunities in field applications, 2) More reliable methods for bonding dissimilar materials such as concrete, steel, and different polymers 3) New opportunities for improved efficiencies in pre-fabrication assemblies, 4) The option to bond over 100% of contact surface areas (as opposed to edge or spot connections only), 5) Secondary supplemental seaming for liability protection in leak-prone locations as desired, and 6) The bonding and application of beneficial paints and coatings 7) New opportunities for the assembly of geosynthetic composites
Results =Film Tear Bond Adhesive connection is stronger than tear strength of the geomembrane Meets most rigorous requirement even for heat seaming Tensile Peel Test of 60 mil (1.5 mm) White Surfaced Geomembrane Adhesively Bonded after Fluoro-Seal Surface Modification
Adhesive bond strength exceeds tear strength of 100 mil (2.5mm) thick HDPE – a remarkable performance for adhesive bonding Film Tear Bond in Tensile Peel Test of 100 mil (2.5mm) Polyethylene Adhesively Bonded After Fluoro-Seal Surface Modification
With Surface Modification Many Different Geosynthetics Can be Reliably Bonded to Similar and Dissimilar Materials Including Concrete and Steel as Shown Here with Geonet
Film Tear Bonds in Tensile Tests of Surface Modified Polyethylene Geomembrane Adhesively Bonded to Steel using Two Different Epoxies
Concrete and Other Dissimilar Surface Connections Can Now be Fully Sealed • Heretofore geomembranes have been limited to batten strips and neoprene gaskets, and expensive embedded strips, Fluoro-Seal surface modified HDPE geomembrane can now be adhesively joined with structural bonding to nearly all surfaces, hard or soft, smooth or rough.
Battening leaks around bolt holes and bolt threads Once saturated, neoprene gaskets will leak Silicone seals of battening do not last Batten Strips and Gasketing Can Also Be Expensive The Batten Strip/Gasket Connections to Concrete in Surface Impoundments Should Not be Expected to Remain Leak Free
Better Concrete Connections can be Made Using Adhesives and Sealants with Surface Modified Geomembranes
In Concrete Block Pullout Tests with Surface Modified HDPE the Adhesive Bond is Stronger than the Concrete
Fluoro-Seal Surface Modified HDPE Adhesively Bonded to Concrete was Subjected to Pullout Tests using Large Flathead Bolts Glued to the Bonded Membrane. When Cut Around the Bolt Head with a Circle Saw and Pulled out with a Tensometer, the Specimens Broke in the Concrete not the Adhesive Connection
Pullout strengths for the adhesively bonded surface modified HDPE were 2 – 8 times as great as the pullout strengths of concrete embedment liners molded into bricks. The fact that adhesive bonding covers a larger area, versus being limited to the locations of embedded studs, means that corresponding pullout resistance per unit area is much higher for the adhesive bonded SMHDPE than for the CEL’s. The Same Tests were Run on Concrete Embedment Liner (CEL) Set into Molded Bricks
Samples at 90 F Samples at 180 F Excellent Bonding to Concrete Held up through Repeated Thermal Cycling Tests as Well. Expansion/ Contraction Forces are too Low to Relax Bonding.
Structural Adhesive Assembly of Dissimilar Materials Applies to Thermoplastics of all Shapes and Configurations When Surface Modified
Polyethylene Pipe and Fittings for Example Can be Joined with the Help of Adhesives and are no Longer Restricted to Sometimes Cumbersome and Expensive Heat Seaming
Surface modifying penetrations and adjacent skirting allows supplementing the construction with properly bonded sealants to provide insurance against leakage Penetrations are Historically the Locations Prone to Leak in Geomembrane Containments
Penetrations are Often Prefabricated from Separate Pieces, and Lend Themselves Well to Surface Modification and Adhesive Assembly
Both Standard and Specialty Penetrations Can Benefit from the Use of Adhesive Connection
Exposed Hazardous Waste Surface Impoundments Require Routine Inspections for Damage Fluoro-Seal surface modification enables do-it-yourself routine repairs, and supplemental sealing for liability protection, in addition to hydrocarbon diffusion resistant containment.
Traditional Repair Options for Such Cases Require Hiring Trained and Specialized Technicians with the Right Equipment- Expensive Over the Impoundment Life
Hardware Store Available Dual Tube Applicators for Two Part Epoxies Can be Employed, using Tape to Hold Epoxy in Place for Cure
Here we see Use of a Dual Tube Epoxy Applicator to Bond Geomembrane to a Concrete Surface, Prior to Connecting with a Second Panel
Trowel-able Sealants and Adhesives Can be Spread to Bond Entire Surfaces of Geomembrane to Concrete and Other Materials for Longterm Durability and Leakage Interception
Sections Bonded to Concrete Offer Built – In Leak Protection and Wrinkle Free Construction Sealed to Concrete, the Membrane Lays Flat without Wrinkles – Note Wrinkles in Unbonded Adjacent Overlapped Panel and Walls
Not Only Does Fluoro-Seal Treatment Make Geosynthetics Bond with Epoxy Adhesives, but the Surface Modification Makes Longterm Application of Paints and other Coatings Possible for Decorative or Performance Related Purposes
Adhesive Bonding and Coating Applications are Essentially Unlimited. Any Assembly which Benefits from Structural Adhesion of Thermoplastics - Bonding to Themselves or Other Substrates Should be Considered. Just Let Your Imagination Soar.
But Adhesion Applications are not the Only Improvements Resulting From Fluoro-Seal Surface Modification…. Fluoro-Seal Treatment Will also… Increase Permeation Resistance And Can • Increase Chemical Resistance • Increase Resistance to Surface Oxidation • Increase Resistance to Stress Crack Initiation • Reduce Depletion of Stabilizers
Geomembranes are in Actuality Quite Permeable to Hydrocarbons • Hydrocarbons permeate geomembranes at much higher rates than water, salts, and heavy metals • In rare situations the vapor phase permeation is even visible, as in the case of this freshly drained geomembrane lined trench, which had leaked kerosene to the underlying concrete, wetting the saturated wall from the backside. • Engineers should be concerned about hydrocarbon permeation, not about moisture permeation, even in dilute situations* *Rowe, K.R. “Geosynthetics and the Minimization of Contaminant Migration through Barrier Systems Beneath Solid Waste”, Keynote Lecture, Proceedings of 6th International Conference on Geosynthetics, Atlanta Georgia, March 1998, pg 27 - 102.
VOC’s Can Permeate This Geomembrane Cover as Can Hydrocarbons the Geomembrane Liner Underneath • Hydrocarbons in dilute solution permeate even faster than in concentrate • This is because lower solubilities in water increase the affinity for and solubility in the geomembrane • For example, toluene permeabilities through HDPE are three orders of magnitude higher for the average of reported aqueous solution permeabilities, versus the average for pure solvent
In Addition to Landfills Many Surface Impoundments Also Contain Hydrocarbon Wastes Which Permeate the Liners For a typically well-inspected installation, permeation is the governing rate for aquifer contamination. It has been calculated that for different reasonable scenarios of clay adsorption and biodegradability, and typical Municipal Solid Waste landfill source concentrations, toluene (which has a drinking water limit of 24 ppb) would range from approximately 5 to 500 ppb in an aquifer 3 m underneath a 60 mil HDPE geomembrane and 2 ft compacted clay composite liner system (Rowe, pg 64). Clearly, the risk of contaminated groundwater is present in this typical case ! The solution to eliminate such risk is to specify very thick clay layers, or to specify better hydrocarbon barriers. Rowe, K.R. “Geosynthetics and the Minimization of Contaminant Migration through Barrier Systems Beneath Solid Waste”, Keynote Lecture, Proceedings of 6th International Conference on Geosynthetics, Atlanta Georgia, March 1998, pg 27 - 102.
Surface Modification Helps Resist Hydrocarbon Absorption and thus the Damaging Effects of Solvent Swell • Peel stress and failure has been known to result from solvent absorption and swell • Hydrocarbon absorption interferes with seam quality, and can cause welds to come open
Fluoro-Seal Treatment can also Provide a Surface More Resistant to Acid Oxidation • For this immersion of unpigmented HDPE sample plaques the upper two sets of specimens were Fluoro-Seal treated. The lower set was not, and shows signs of acid etching.
Acid Runoff in this Trench at a South American Mine, Together with High Altitude Sunlight, has Oxidized and Degraded with Brittle Fracture this HDPE Drainage Ditch Liner . The Geomembrane could have benefited from the extra protection of Surface Modification.
Surface Degradation can Lead to Other Forms of Premature Failure, Including Stress Cracking
Fluoro-Seal Treatments have been Shown to Resist Stress Crack Initiation As tested in constant load stress crack testing, ASTM D 5397, Fluoro-Seal surface modification has enabled otherwise poor stress crack resistant resins to perform well.
By Significantly Reducing Hydrocarbon Diffusion, Fluoro-Seal Treatment Can Extend the Time of Migration and Depletion of Geomembrane Antioxidants and Thus Extend the Lifetime of Geomembranes • Antioxidants are hydrocarbons of varied mobility in thermoplastics • Antioxidant depletion time is a function of extraction rate, a permeation/diffusion phenomenon • Their mobility out of a geomembrane (depletion) is thus restricted by Fluoro-Seal treatment of the surface
Fluoro-Seal Reactive Gas Initiated Surface Modification of Geosynthetics Improves Key Properties Related to : Improved Assembly, Improved Installation, and More Secure Containment Best Available Technology has Improved!