Full Answer
Why to use polyurethane foam?
- Critical Environment Buildings/structures
- Museums and Art Storage
- Historic Restoration and Renovation
- Clean Rooms
- Hospitals
- Food Processing
- Cold Storage
- Extreme Indoor-Air-Quality Environments
- High-Moisture Environment Buildings/structures
- Indoor Pools and High-Moisture Environments
Is great stuff polyurethane foam?
Great Stuff is simply polyurethane foam. It's quite flammable when released from the can due to the use of a potentially explosive gas propellant. And, even after it hardens, the foam remains flammable when subjected to temperatures above 240 F (116 C).
Does polyurethane foam absorb water?
Rigid Polyurethane foam shows very little propensity to absorb water due to its closed-cell structure and hydrophobic nature. The water absorption in small scale test in laboratory is usually below 2 %. For this reason, rigid polyurethane foam outperforms other insulation materials regarding water resistance e.g. in wall or roof applications.
What are the medical uses of polyurethane foam?
Polyurethane foam (PU) Polyurethane foam (PU) is characterized by its light weight, resiliency, low odor and high resistance to mildew. It provides excellent cushioning and is used extensively in applications such as bedding. This open-celled foam is used regularly in medical packaging where abrasion resistance is required.
Is polyurethane foam hydrophilic?
The hydrophilic polyurethane foam is prepared by the materials in parts by weight: 50-75 parts of hydrophilic polyether A, 25-50 parts of polyether polyol B, 36.5-42 parts of TDI (toluene diisocynate), 0.5-1.5 parts of diethanol amine, 0.12-0.3 part of polyurethane catalyst A-33, 0.5-1.5 parts of silicon oil and 3 ...
What is hydrophobic polyurethane?
Hydrophobic polyurethanes naturally repel water (similar to the way oil would repel water and stay separate if you were trying to mix them in a glass). These products push water out of the area in question as they expand. Hydrophobics are used with catalysts which allow you to adjust the set time.
What is Polyurethane foam injection?
Polyurethane foam injection is a slab jacking procedure that is uses much lighter material compared to traditional cement grout that weighs a whopping 140 pounds per cubic foot. The lighter material allows for a greater chance of long term success.
What is hydrophobic grout?
Simply translated as a “water fearing” material, hydrophobic grouts have little to no affinity for water. These grouts need very little, if any, water to react and cure.
How do you increase hydrophobicity?
The amount of hydrophobicity can be increased or decreased by changing the contact angle. Increasing the contact angle by more than 150 degrees increases the hydrophobicity. Nanoparticles such as silicon oxide, titanium oxide, aluminum oxide, iron oxide, and silver have been used for making hydrophobic surfaces.
What is foam grout?
Chemical Grout Foam is a hydrophilic liquid similar in viscosity to medium weight motor oil. The grout can be injected directly into a leaking crack, fracture, hole or joint. After injection, grout will foam to expand and fill the void forming a tight, impermeable, elastomeric gasket or seal.
How much does PolyLevel cost?
How Much Does PolyLevel Cost? PolyLevel costs about $15 per square foot or around 30% to 40% more than standard mudjacking. PolyLevel is a patented, high-density polyurethane foam used for heavy-duty concrete stabilization projects like home foundation and driveway work. This polyfoam cures in as few as 30 minutes.
How long does PU injection last?
Furthermore, PU injection is a very effective method to repair water leakages and it has a very good lifespan. Because of the strong adhesiveness property of polyurethane, it can form a very strong bond with the concrete or cement surfaces and can last many years.
How long does poly foam last?
The polyurethane foam Liftech uses to complete repairs will last indefinitely – through your lifetime and well beyond. It cures within minutes as a solid, impermeable structure that adheres directly to the concrete. It is not susceptible to fracture or failure.
What is polyurethane grout?
Polyurethane grouting involves the injection of expanding polyurethane to fill and seal cracks and voids and re-level slabs.
What is hydrophilic waterstop?
Hydrophilic waterstops are elements of a concrete structure, intended to prevent moisture infiltration. Hydrophilic means "water-loving", so these hydrophilic waterstops swell in the presence of moisture. They can be used to seal concrete joints, but also to seal formwork spacers or tie rods.
What is hydrophilic resin?
Hydrophilic (hydro meaning 'water', philic meaning 'has an affinity for') resins seek out water in a crack. They chase the water and absorb into the tight micro-cracks and pores of the concrete. Hydrophobic (hydro - water, phobic - fearing) resins repel water in a crack.
How is polyurethane foam formed?
Most of the Polyurethane PU Foam resins are formed through a chemical reaction between an isocyanate (R–NCO) and a polyol (R–OH) components [134]. Those two components are mixed in specific volumetric proportions according to targeted product specifications. A large amount of carbon dioxide is produced during the chemical reaction, which causes the volumetric expansion of the mixture and the formation of a spongy structure where the gas bubbles are trapped, and relatively rigid walls surround gas bubbles (cells) are formed [48]. Carbon dioxide production requires the presence of water, which reacts with the isocyanate group. In the absence of water, a low boiling point chemically inert swelling agent is used, which is vaporized and absorbs most of the polymerization heat [22].
What are the two types of polyethylene foam?
Sidek et al. [113] reported that there are two types of Polyethylene PU foam, namely, hydrophobic and hydrophilic PU foams. Hydrophobic PU is water-resistant, whereby the liquid form reacts and expels water from the voids in the soil. On the other side, Hydrophil ic PU reacts with the presence of water to form a gel and hardens to form flexible PU. If being exposed to water after solidification, the diffusion of the highly insulating blowing agents and the infusion of water vapor into the cells are the mechanisms that govern the foam-water interface [20]. A direct effect of these two mechanisms is the suction of the water and the release of the CO 2 into the soil (see Section ‘Physico-chemical interaction with the soil’), which affects the behavior of the injected expansive soil. This phenomenon still needs investigations to be developed.
What is polyethylene foam used for?
Polyethylene foam is often used as a conditioning and stabilizing agent for the pavement subbase layer and foundation systems concerned with relative movement problems [125]. However, few studies showed that using PU foam might improve the soil bearing capacity due to the expected reduction in void ratio, and the limitation of the soil volume change [113]. A practical study [103] showed that stabilizing the marine clay with the polyurethane improved the shear strength of the marine clay from 75 kPa to 250 kPa, which means 230% increase in the shear strength.
What is the primary reaction between the injected polymeric stabilizing agents and the clay soil?
The primary reaction between the injected polymeric stabilizing agents and the clay soil is caused by the isocyanate component (R–NCO) of the polyurethane. Those active groups of polyurethane can react with water and produce CO 2. As a side reaction, the additional isocyanate reacts with the formed urea and intertwine with polyurethane linkages already present in the prepolymer as it cures as described in Equations D and E.
What is PU foam used for?
It is commonly used in many applications, such as packaging, cushioning, space-filling, and insulation [31]. Open cells are usually suitable for use in sound insulation, whereas closed-cell foams are suitable for use in thermal isolation [45] as it has excellent thermal insulation properties in the −196 °C to 130 °C temperature range [34]. The mechanical strength and fast processing also make it an appealing option for many industries, including refrigerators and sandwich panels, where closed-cell PU foams dominate the market [69].
What is soil reinforcement?
Soil reinforcement is a mechanical means of stabilizing weak soils that involves the use of fibrous materials as geosynthetics (geogrid, geocomposite, geotextile, geocell, and geonet) natural or synthetic randomly distributed fibers [54]. The main objective of the soil reinforcement is to increase the bearing capacity and strength of the soil. It can also be described as a soil stabilizer. Some manufacturers have promoted many geogrids as an alternative to lime stabilization for heavy clays that contain sulfates [123]. However, Hardcastle [53] concluded that it is difficult to see how it could be used to prevent swelling of the high expansive clay mineral soils.
What happens when water molecules are oriented on the clay surface?
After negative charges attract the water molecules to the clay particles, a gap between the clay surface is expressed, causing expansion or swelling of the soil.
Low-Density U-19 (105) Energy Absorbing Foam
Properties include a low-density energy absorbing foam ideal for combat and athletic impact protection padding. The properties of our U-19 (105) energy absorbing foam are as follows:
Poly Labs: Hydrophobic EA Foam Experts
The team at Poly Labs works with leading OEM’s of the world’s most critical protection and safety products: military communications gear, audio components, footwear parts, industrial safety tools, medical equipment, and protective padded helmet lining materials for athletes, production workers and firefighters.
Product
Sika #453579 SikaFix HH+ Hydrophobic, Expanding, Polyurethane, Chemical Grout, 100% Solids, Easy to Apply, One Component with Accelerator, Amber/Transparent Liquid Color. 5 Gallon Pail. Price/Pail.
Description
Sika #453579 SikaFix HH+ is a hydrophobic polyurethane foam grout that, when used with accelerator, is designed to stop water infiltration and fill voids outside a structure or joint and cracks in concrete structures. This product may also be used in applications with high pressure flowing water.
USES
Use to fill joints or cracks in concrete structures that exhibit some movement.
How does hydrophobic foam work?
Two component hydrophobic systems can be formulated where one side contains the catalyst and the other side contains the reacting ingredients. These systems require very little water to initiate the foaming reaction. There is typically enough water present in a crack to initiate the reaction. Thus unlike hydrophilic systems, where water is typically first mixed with the hydrophilic, these hydrophobic systems do not react until already present in the crack and have time to fully permeate all parts of the crack before beginning to foam. A hydrophilic system will usually be foaming before entering the crack, and can clog up the mixing unit before entering the crack. A hydrophobic system has time to not only permeate the crack but to fill any void behind the crack. A void is a separation of the foundation wall and the back-fill which can allow collection of water behind the crack and cause it to leak. A hydrophobic will react with the water, filling the void as it forms a rubber membrane behind the foundation which blocks water from reaching the crack to cause leaking. These systems work very well in residential basement concrete crack repair, especially when packaged in dual cartridges.
What is hydrophobic polyurethane used for?
Use of Hydrophobic and Hydrophilic Polyurethanes for Crack Injection. Polyurethane foams used in concrete repair to prevent water penetration through concrete cracks are said to be either hydrophobic or hydrophilic in behavior.
What happens when water is again present in a concrete crack?
When water is again present, the foam can absorb the water and return to its original size, as would a sponge (at least theoretically). A typical hydrophilic system is very flexible and has good adhesion to concrete, and thus bonds well to the sides of a concrete crack.
What is hydrophilic foaming?
A hydrophilic system acts like a sponge and will absorb as much water as is available in its surroundings during the foaming process. It reacts with the amount of water needed for reaction and subsequently contains the excess water within its structure, as would a sponge.
What is hydrophobic system?
A hydrophobic system has time to not only permeate the crack but to fill any void behind the crack. A void is a separation of the foundation wall and the back-fill which can allow collection of water behind the crack and cause it to leak.
How much water does a hydrophobic system absorb?
A typical hydrophobic system will expand up to 30 times its initial volume.
Can hydrophobic concrete be used for crack repair?
Today, there are hydrophobic formulations available which are flexible and stable, and are suitable for concrete crack repair. They bond well to concrete, do not shrink even in the absence of water, and can expand enough to fill voids economically.