Hydrophilic Polyurethanes
Polyurethane
Polyurethane is a polymer composed of organic units joined by carbamate links. While most polyurethanes are thermosetting polymers that do not melt when heated, thermoplastic polyurethanes are also available.
Polyurethane
Polyurethane is a polymer composed of organic units joined by carbamate links. While most polyurethanes are thermosetting polymers that do not melt when heated, thermoplastic polyurethanes are also available.
Why polyurethane is oleophilic?
When the thin film is subjected to oxygen plasma treatment, the hydrophobic property of the thin film is changed, and the thin film is converted into the hydrophobic underwater oleophobic thin film...
Why is polypropylene hydrophobic?
Polypropylene is hydrophobic and will not absorb water in the fibre. Water “wicks” away from the skin and through the fabric to the face for quick evaporation. Colour Properties Fade-resistant. Polypropylene is dope-dyed (melt-dyed), which is the most “colourfast” of any colouring methods, and produces fibres and yarns that are ...
What are some examples of hydrophilic substances?
There are many hydrophilic molecules examples, such as:
- Glucose (sugar)
- Starch
- Cellulose
- Amino acids (some)
- Ethanol
- Methanol
- Sodium chloride
- Sodium hydroxide
Are polypeptides hydrophilic or hydrophobic?
sensitivity of elastin-like polypeptides is reported. To this end, a rectangular sheet made using the DNA origami technique is functionalized with these peptides and by applying changes in salt concentration the hydrophilic– hydrophobic phase transition of these peptides actuate the folding of the structure.
What is hydrophilic foam made of?
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 ...
Is hydrophilic polyurethane safe?
According to ISOPA (the European Isocyanate Producers Association), polyurethane foam is safe, sustainable, and altogether a bit of a miracle product.02-Mar-2017
Is polyurethane foam hydrophobic?
Polyurethane foams used in concrete repair to prevent water penetration through concrete cracks are said to be either hydrophobic or hydrophilic in behavior.
What is hydrophilic resin?
Hydrophilic 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. They resist movement towards wet areas and will not absorb into tight micro cracks and pores in the concrete.
How good is water based polyurethane?
A well-engineered, water based polyurethane will be equal in clarity to oil-based polyurethane. The main difference is usually color: water based polyurethanes are completely clear and (again, if well engineered) will not yellow over time. This is ideal if you want the natural color of your wood to remain constant.05-Aug-2020
Is water based polyurethane toxic?
Yes, water-based polyurethane is toxic. But it's slightly less toxic than oil-based polyurethane. This is because the chemical used to make water-based polyurethane contains fewer quantities of compounds containing VOCs (volatile organic compounds). So water-based polyurethane side effects aren't as harsh as oil.
What is PU plastic?
Polyurethane is a polymer joined by urethane links. These links are formed by reacting a di- or poly-isocyanate with a polyol. Polyurethane is unique in that it is not manufactured like many other plastics. Most polymers, such as polyethylene, are produced in the form of a powder and then molded into a desired form.
Why do hydrophobic molecules repel water?
Water does not tend to wet hydrophobic surfaces; rather, the droplets stay beaded up with high values of contact angle. Hydrophobic molecules called hydrophobes repel bodies of water and, owing to the fact that hydrophobes are non-polar, they attract other neutral molecules and non-polar solvents.19-Dec-2019
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. Once cured, hydrophobic grouts resemble a rigid foam, containing an open cell structure (see photo).
Is resin hydrophobic or hydrophilic?
Epoxy polymers are generally hydrophilic due to the presence of polar epoxy groups.25-Jun-2017
Are sugars hydrophobic or hydrophilic?
Each of the carbon atoms is also joined to at least one hydrogen atom and to one oxygen atom. The presence of all this oxygen in the structure of the glucose molecule ensures that it is strongly hydrophilic ('loves' water).
Is dental composite hydrophilic?
In order to make the adhesive system compatible with the silorane-based composite resin, the bonding agents for such composite resins contain hydrophobic dimethacrylate monomers (70–80 wt%) and are devoid of hydrophilic HEMA monomer; therefore they are hydrophobic [22].
What is the difference between hydrophobic and hydrophilic?
But, to a contractor, these terms can mean a world of a difference. Hydro means water while phobic means “to fear” and philic means “to love”.
Does AP seal 500 absorb water?
Some hydrophilic materials will keep absorbing water (10-15 times their original volume). Others (such as our AP Seal 500) only absorb as much water as is necessary for their reaction and then they reject the rest. Yes, hydrophilic gels will shrink like crazy in the absence of water, but the AP Seal 500 won't.
Is Alchemy Spetec hydrophobic or hydrophilic?
Alchemy-Spetec offers both hydrophobic and hydrophilic polyurethanes, so it is important to be aware of the differences between the two types.
Do hydrophilic polyurethanes need a catalyst?
This characteristic allows for a very strong chemical and mechanical bond, as water helps pull the material into the pores of the concrete. These products do not require a catalyst.
Injection Foams, Resins and Gels
Polyurethane chemical injection grouts are separated into two distinct categories – hydrophobic and hydrophilic
Hydrophobic Polyurethanes
Hydrophobic can be translated as (hydro = ‘water’, phobic = ‘aversion/fear’) a “water fearing” material – meaning that hydrophobic grouts have little affinity to absorb water into their structure. However, water-blown polyurethane foams do need some water to react, polymerize, and expand.
Hydrophilic Polyurethanes and Acrylics (Acrylates)
Hydrophilic can be translated as (hydro = ‘water’, philic = ‘loving’) a “water loving” material – meaning that hydrophilic grouts have greater affinity to absorb water into their structure and can form gels. During reaction and polymerization, hydrophilic grouts absorb and retain water molecules, resulting in a very flexible product.
Wisconsin Foam Products
Distributor of closed cell polyurethane foam for the medical, healthcare, electronics, furniture, upholstery, bedding, aerospace, defense, agricultural, construction, cosmetics and marine industries. Comes in sheet, roll and insert forms.
Comcast Urethane
Custom manufacturer of micro-cellular hydrophilic urethane foam with flame resistant properties. Flexible and Integral skin urethane foams are available. Offered in densities ranging from 6 lbs. to 16 lbs. in different colors.
Unique Fabricating
ISO 9001:2008 certified custom manufacturer of hydrophilic polyurethane foam for automotive, medical grade & marine applications. Various products include cushions, armrests, office furnishings, restraints, wheels, bumpers, mattresses, pillows, medical supports, pet beds, inserts, sub straights, housings, backing, dampeners, gaskets & dunnage.
Bauer Cases
Manufacturer & distributor of a complete line of packaging, shipping & carrying cases & accessories. Accessories include custom foam cushioning systems, foam insulation & molded foam cases. Included are rotationally-molded, injection-molded, blow-molded, aluminum, thermoformed & soft-side cases.
Lafayette Supply
Distributor of foam including expanded polystyrene (EPS), polystyrene, polyurethane, urethane and hydrophilic polyurethane foam. Available in roll, pouch and dispenser pack form. Foam rolls such as anti-static and cohesive foam rolls are available in perforated and non-perforated types.
Custom Pack, Inc
Custom fabricator of hydrophilic polyurethane foam available in various densities & colors. Capabilities include assembly, custom designing & prototyping. Polyurethane foam is suitable for electronics, appliance, cosmetic & instrumentation applications. IATA & 95 kPa certified.
Califoam Products
Manufacturer of standard and custom recyclable foam made from urethane, hydrophilic polyurethane, polyurethane and polystyrene. Foam is CFC/HCFC free. Fabrication processes include die cutting, hot wire and hot plate lamination.
What is Sikafix HH?
SikaFix® HH Hydrophilic is a nonflammable hydrophilic polyurethane resin designed to form a flexible gasket or plug joints and cracks in concrete from water infiltration. In its uncured form, SikaFix® HH Hydrophilic is a pale yellow liquid. When it comes in contact with water, the grout expands quickly and cures to a tough, flexible, adhesive, closed cell foam that is essentially unaffected by mildly corrosive environments.
Is grout flammable?
Contains no volatile solvents. Non-flammable. Free Foam expands to 6 times its liquid volume.
What is hydrophilic grout?
Hydrophilic polymer injection gel grouts achieve a mechanical bond in rough areas of the concrete as they absorb deep into the pores and micro cracks of the concrete. Hydrophilic resins can achieve a strong bond to the wet concrete which can be superior to hydrophobic resins, which rely more on high injection pressures to penetrate into fine pores and rely more on a compression seal created by the reactive expansion.
Which resin is stronger, hydrophobic or hydrophilic?
Hydrophilic resins can achieve a strong bond to the wet concrete which can be superior to hydrophobic resins, which rely more on high injection pressures to penetrate into fine pores and rely more on a compression seal created by the reactive expansion.
Does water need to be in the substrate to form gel?
The presence of sufficient water in the substrate is necessary for the product to form a gel. It may be advisable to introduce water prior to injection. In areas of very little water content and little counter pressure the product may expand to a foam.
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 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.
Is hydrophobic foam brittle?
Historically, most hydrophobic foams were rigid and could be brittle if not carefully formulated to be more stable. As a consequence, concrete crack repair contractors initially used hydrophilic systems to stop water. Today, there are hydrophobic formulations available which are flexible and stable, and are suitable for concrete crack repair.
Can hydrophobic foam be used to repair cracks in concrete?
It is also effective in situations where water is always present. It cannot be helpful in dealing with a void behind a crack, where the hydrophobic foams really shine. In summary, hydrophobic systems, which have been modified for flexibility and good adhesion, are excellent choices for most basement concrete crack repair.
Why is polyurethane used in soil stabilization?
Polyurethanes are usually used to fill voids and stabilize soil because of their low viscosity, high expansion rates, and ability to set up under wet conditions without diluting. Hydrophobic resins repel water. When injected into loose soil or voids, they expand and displace any water that is present. The rigid hydrophobic soil stabilization materials that are on the market expand up to 1 ,000% in the soil and form a strong, impermeable mass.
How effective is hydrophobic resin?
There is no doubt that hydrophobic resins can be very effective at stopping water leaks. They will expand and fill up a wet crack as well as most hydrophilic resins . The failure will usually occur a few months after the job is finished. If it happens during the warranty period, the contractor will have to return to the job and fix it again. All of the profit made on the job goes out the window. The only one who benefits is the hydrophobic material supplier.
How much water does hydrophilic soil stabilization absorb?
The rigid hydrophobic soil stabilization materials that are on the market expand up to 1 ,000% in the soil and form a strong, impermeable mass. Hydrophilic resins absorb water. The hydrophilic soil stabilization materials that are on the market absorb as much water as they come into contact with during initial cure.
What resins seek out water?
Hydrophilic resins seek out water in a crack. Learn why that matters when sealing hairline cracks. 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.
How long does it take for polyurethane to cure?
The initial cure is the time when the polyurethane resin foams up. The final cure may take up to 24 hours. It is during this time that hydrophilic resins bite into the pores and micro cracks of the concrete.
Does hydrophobic resin repel water?
Since hydrophobic resins repel water, they will not penetrate these areas. They may be forced in using high pressure, but the water will act as a bond breaker between the polyurethane foam and the concrete resulting in extremely low bond strengths.
Can hydrophilic resin be used for crack injection?
hydrophilic resins should always be used for crack injection. Prime Resins. News. Why crack injection should always be performed with a hydrophilic polyurethane.