Poloxamer EO/PO Block Copolymer(CAS#9003-11-6)–Nonionic Surfactant & Demulsifier

1. Properties:

• Appearance and Physical Form: EO/PO block copolymers (poloxamers) are supplied as colourless to pale yellow clear viscous liquids at low EO content, as white to off-white waxy pastes or solids at higher EO content, and as free‑flowing granular powders or beads at the highest EO content. The product is odourless or has a faint characteristic odour and is non‑toxic.
• Solubility: The solubility of EO/PO block copolymers depends on the EO content. Low‑EO grades (HLB 1–8) are oil‑soluble and water‑insoluble, making them ideal for W/O emulsification and defoaming applications. High‑EO grades (HLB 14–29) are water‑soluble and function as excellent O/W emulsifiers, solubilisers, and thickeners. All grades are soluble in alcohols and various organic solvents. The “reverse solubility” property—decreasing water solubility with increasing temperature (cloud point)—is a key feature exploited in defoaming and foam control.
• Chemical Properties: EO/PO block copolymers are nonionic triblock or diblock synthetic polymers composed of hydrophilic polyethylene oxide (PEO) blocks and hydrophobic polypropylene oxide (PPO) blocks. This unique amphiphilic structure allows the polymer chains to self‑assemble in aqueous solution into micelles, contributing to their surface‑active properties. Key parameters include:
  • Adjustable EO/PO Ratio: By varying the relative lengths of EO and PO blocks, the HLB can be precisely tuned from 1 (lipophilic) to 29 (hydrophilic), enabling customisation for specific surfactant roles. The cloud point typically increases with EO content.
  • Surface Activity: EO/PO copolymers exhibit excellent surface tension reduction, wetting, spreading, and emulsifying properties comparable to conventional nonionic surfactants, but with significantly lower foaming and higher chemical stability.
  • Demulsification: For oilfield crude oil dehydration, EO/PO copolymers function by displacing natural emulsifiers from the oil‑water interface, causing water droplets to coalesce and separate from the oil phase. Reverse EO/PO block copolymers are particularly effective for breaking water‑in‑oil (W/O) emulsions and promoting rapid separation.
  • Defoaming: The unique “reverse solubility” (cloud point) behaviour causes the copolymer to become insoluble above a certain temperature, spontaneously adsorbing at air‑liquid interfaces to destabilise foam bubbles, providing exceptional foam control in high‑temperature processes without leaving residues.
  • Chemical Stability: EO/PO copolymers are resistant to hydrolysis over a wide pH range (2–12) and remain stable at elevated temperatures (up to 150–200°C depending on grade), significantly outperforming conventional ester‑based surfactants under harsh conditions.
  • Low Toxicity & GRAS Status: Many EO/PO copolymer grades have low acute oral toxicity (LD₅₀ > 5,000 mg/kg), are non‑irritating to skin and eyes, and are approved for use in pharmaceutical, food, and personal care applications under GRAS (Generally Recognized as Safe) and USP/NF monographs.
  • Thermoreversible Gelation: Certain high molecular weight poloxamers (e.g., Poloxamer 407) form thermoreversible hydrogels that are liquid at low temperatures and gel at body temperature, a property exploited in drug delivery, topical formulations, and tissue engineering.

2. Applications:

Oil & Gas Industry – Crude Oil Demulsification (Primary):

• Crude Oil Demulsifier: As the primary application, EO/PO block copolymers are widely used as crude oil demulsifiers (dehydrating agents) to break water‑in‑oil (W/O) emulsions that form during oil production. The copolymer displaces natural emulsifiers (asphaltenes, resins, naphthenic acids) from the oil‑water interface, allowing water droplets to coalesce and separate from the crude oil phase. This provides efficient water removal, lower BS&W (basic sediment & water) content, reduced demulsification time, enhanced oil recovery, prevention of pipeline hard‑scale formation, and reduced operating costs.
• Oilfield Drilling and Production Fluids: EO/PO copolymers serve as defoamers, wetting agents, lubricity enhancers, and emulsion stabilisers in drilling fluids and production chemicals. Their low‑foaming and high‑temperature stability make them ideal for deep‑hole, high‑temperature wells where conventional surfactants degrade.
• Oilfield Friction Modifier: Certain grades function as friction modifiers in drilling and fracturing fluids, reducing torque and drag in directional drilling operations.
• Secondary Oil Recovery (EOR): EO/PO copolymers are used as mobility control agents in enhanced oil recovery (EOR) operations, improving sweep efficiency and oil displacement.

Water Treatment & Industrial Defoaming:

• Water Treatment Defoamer / Antifoaming Agent: The unique reverse solubility of EO/PO copolymers makes them highly effective defoamers in water treatment applications, including cooling towers, boiler feed water, aeration basins, clarifiers, and industrial effluent treatment. They instantly knock down foam without forming oily films or leaving residues.
• Wastewater Treatment Flocculant: EO/PO copolymers function as flocculants and coagulant aids in municipal and industrial wastewater treatment plants, improving solids capture, enhancing sludge dewatering, and clarifying final effluent.
• Reverse Osmosis (RO) Pretreatment: Used as a defoamer and antifoam in RO feed water to prevent membrane fouling from foam‑entrained particulates.

Industrial & Institutional Cleaning (I&I):

• Rinse Aids for Automatic Dishwashing: The low surface tension and low‑foaming properties of EO/PO copolymers make them particularly efficient rinse aids in automatic dishwashing detergents, providing sheeting action to eliminate spotting and filming on glassware, dishes, and cutlery.
• Clean‑In‑Place (CIP) Formulations: Widely used in CIP cleaning for food, dairy, beverage, and brewery applications, providing effective wetting and defoaming without leaving harmful residues.
• Industrial Degreasers & Hard Surface Cleaners: Improve wetting, penetration, and soil removal in industrial degreasers, floor cleaners, and all‑purpose hard surface cleaners.
• Dairy & Brewery Bottle Washers: EO/PO copolymers perform exceptionally in high‑temperature bottle washing applications, where their thermal stability and defoaming properties eliminate caustic foam carryover.

Metalworking & Metal Treatment:

• Metalworking Fluids (MWF): EO/PO copolymers are ideal additives for soluble oils, semi‑synthetic fluids, and synthetic metalworking fluids, serving as emulsifiers, lubricity enhancers, corrosion inhibitors, and defoamers. They improve cooling, chip transport, tool life, and surface finish quality.
• Metal Cleaners: Used in alkaline and neutral metal cleaning formulations to remove oils, greases, and shop soils prior to electroplating, phosphating, or painting.
• Industrial Lubricants: EO/PO copolymers function as synthetic lubricants and lubricant base stocks for compressors, gears, hydraulic systems, and bearings, offering low pour points, high viscosity indices, and excellent compatibility with various industrial fluids.

Agrochemicals (Pesticides & Adjuvants):

• Pesticide Emulsifier: EO/PO block copolymers serve as registered inert ingredients in pesticide emulsifiable concentrate (EC) formulations, providing stable O/W emulsions for herbicides, fungicides, insecticides, and plant growth regulators.
• Agricultural Adjuvants: As spray adjuvants, EO/PO copolymers improve active ingredient dispersion, reduce spray drift, enhance droplet wetting and spreading, increase leaf penetration, improve rainfastness, and boost overall biological efficacy.
• Fertiliser Additives: Used as suspending agents, wetting agents, and defoamers in liquid fertiliser formulations and suspension concentrates (SC).

Paper & Pulp Industry:

• Paper Mill Defoamer / Antifoam: EO/PO copolymers control foam in paper machine white water systems, pulp washing, screening, and effluent treatment operations, preventing defects and improving machine efficiency.
• Coating Binder & Dispersant: Used as coating binder and pigment dispersant in paper coating formulations for higher paper smoothness, improved gloss, and better print quality.
• Pulp Processing: Functions as a wetting agent and defoamer in various pulping and bleaching stages.

Textile Industry:

• Textile Lubricant / Fiber Finish: EO/PO copolymers are effective textile lubricants (fiber finishes) for spinning, weaving, and knitting operations, reducing yarn‑to‑metal friction, minimising fibre breakage, and providing antistatic properties without leaving tacky residues.
• Warp Sizing Additive: Improves sizing agent penetration and film flexibility, enhancing weaving efficiency.
• Dyeing & Printing Auxiliary: Functions as a wetting agent, dispersant, and defoamer in dye baths and textile printing pastes.

Pharmaceutical Industry:

• Tablet Binder & Excipient: Poloxamer 188 and other poloxamer grades are widely used as tablet binders, fillers, and wet granulation excipients in solid dosage forms, improving tablet hardness, cohesion, and disintegration profiles.
• Drug Solubiliser & Emulsifier: EO/PO copolymers are one of the few synthetic emulsifiers approved for intravenous emulsions, serving as solubilisers for poorly water‑soluble drugs, emulsifiers for parenteral fat emulsions, and stabilisers for liposomal and nanoparticle drug delivery systems.
• Gel Formers (Thermoreversible Hydrogels): High molecular weight poloxamers (e.g., Poloxamer 407) form thermoreversible hydrogels that are liquid at refrigerated temperatures and gel at body temperature, used in topical formulations, ophthalmic solutions, injectable depot formulations, tissue engineering scaffolds, and wound dressings.

Cosmetics & Personal Care:

• Thickener & Gel Binder: Poloxamers are widely used as thickening agents and gel binders in lotions, creams, gels, shampoos, conditioners, and antiperspirants, providing smooth texture, shear‑thinning behaviour for easy application, and improved formulation stability.
• Emulsion Stabiliser: Prevents oil‑water separation in cosmetic emulsions, improving product appearance and shelf life.
• Solubiliser for Oily Ingredients: Enhances the solubilisation of water‑insoluble ingredients (fragrances, essential oils, preservatives, vitamins) in aqueous personal care formulations, increasing clarity and bioavailability.
• Film Former: Forms transparent, flexible films on skin and hair, providing hold, protection, and conditioning benefits.
• Skin Conditioning Agent / Surfactant: Acts as a mild, non‑irritating surfactant and conditioning agent in cleansers, makeup removers, and shaving products.

Paints, Coatings & Inks:

• Coating Defoamer: EO/PO copolymers are effective defoamers in water‑based paints, latex coatings, printing inks, and pigment dispersions, preventing foam defects (cratering, pinholes) and improving surface finish.
• Pigment Dispersant: Functions as a dispersant for pigments and fillers, preventing flocculation, reducing viscosity, and improving colour development.
• Wetting Agent: Enhances substrate wetting of coatings on low‑energy surfaces (plastics, polyolefins, contaminated surfaces), reducing crawling and improving adhesion.

Other Industrial Applications:

• Polyurethane Foam Production: Used as a foam stabiliser and cell‑opening agent in flexible and rigid polyurethane foam formulations.
• Construction Chemicals: Employed as air‑entraining agents in concrete, water‑reducing admixtures, and dispersion agents for cementitious grouts.
• Leather Processing: Used as a wetting agent, degreaser, and fatliquoring emulsifier in leather tanning and finishing.
• Adhesives & Sealants: Functions as a wetting agent, defoamer, and rheology modifier in water‑based adhesives, pressure‑sensitive adhesives, and sealants.
• Ceramics: Used as a binder and plasticiser in ceramic body formulations and glaze suspensions.
• Fermentation & Bioprocessing: EO/PO copolymers are used as defoamers in fermentation processes (monosodium glutamate, lactic acid, citric acid production, antibiotics, enzymes), eliminating destructive foam without inhibiting microbial growth.
• Food Processing: Certain EO/PO copolymers are approved as food additives (E1520 in some jurisdictions), used as defoamers, processing aids, and anti‑dusting agents in food production, beverage processing, and food washing operations.

3. Preparation Method:

• Laboratory Method: EO/PO block copolymers are synthesised in a high‑pressure stainless steel stirred autoclave via sequential anionic ring‑opening polymerisation. A monofunctional or difunctional initiator (propylene glycol, ethylene glycol, glycerol, pentaerythritol, or butanol) is reacted with propylene oxide (PO) in the presence of a basic catalyst (KOH, NaOH) at 120–150°C under pressure to build the hydrophobic PPO block. After the PO polymerisation is complete, ethylene oxide (EO) is added to the same reactor, where it polymerises onto both ends of the PPO chain in the presence of the same catalyst, producing the hydrophilic PEO blocks, forming a PEO‑PPO‑PEO triblock copolymer.
• Industrial Process: Industrial production of high‑quality EO/PO copolymers follows a continuous or batch polymerisation process:
  1. Initiation: An initiator alcohol or polyol (e.g., propylene glycol, butanol, or glycerol) is charged to a high‑pressure stirred autoclave with an alkaline catalyst (typically KOH or NaOH).
  2. Propoxylation: Propylene oxide monomer is fed into the reactor under controlled temperature (120–150°C) and pressure (3–5 bar), polymerising to form the hydrophobic polypropylene oxide (PPO) block. The PO feed amount determines the molecular weight of the PPO block.
  3. Ethoxylation: After the desired PPO block length is achieved, ethylene oxide monomer is introduced under similar conditions (140–160°C, 2–4 bar) to polymerise onto the free hydroxyl ends of the PPO chain, forming the hydrophilic polyethylene oxide (PEO) blocks. The EO:PO molar ratio (typically 10:90 to 90:10) determines the final HLB value and surfactant properties.
  4. Neutralisation & Purification: The crude copolymer is neutralised with an acid (e.g., phosphoric acid) to remove residual catalyst, filtered, and vacuum stripped to remove unreacted monomers, water, and volatile byproducts.
  5. Product Finishing: The purified copolymer is cooled, optionally flaked or milled to the desired physical form (liquid, paste, flakes, powder, beads), and packaged. Key quality parameters include molecular weight (by GPC or hydroxyl number), EO/PO ratio (by NMR or titration), cloud point (1% aqueous solution), HLB value, viscosity, colour (APHA), residual catalyst content, and residual ethylene oxide/propylene oxide monomers (<1 ppm for pharmaceutical and food grades).

4. Safety Information:

• Hazard Classification: According to GHS/CLP Regulation (EC) No 1272/2008, EO/PO block copolymers (poloxamers) are generally classified as non‑hazardous or of very low hazard. Most industrial, pharmaceutical, and food grades require no hazard label under CLP. However, high‑dust solid grades may carry hazard statement H335 (May cause respiratory irritation). EINECS: 225‑208‑0. Hazard symbol: None (for most grades) or GHS07 (for dusty powder grades). Signal word: None (most grades) or Warning (dusty grades). UN Number: Not assigned (non‑hazardous for transport). The product is not classified as flammable, explosive, or environmentally hazardous under standard criteria. Regulatory bodies such as NICNAS (Australia) consider EO/PO copolymers to be “polymers of low concern.”
• Health Hazards:
  • Inhalation: Inhalation of airborne dust (solid grades) may cause mild respiratory tract irritation, coughing, or sneezing in sensitive individuals. Prolonged or repeated exposure to high dust concentrations may cause respiratory discomfort. Liquid/viscous grades present minimal inhalation hazard.
  • Skin Contact: Generally non‑irritating to intact skin. Due to low dermal absorption, no serious health issues are expected. Prolonged or repeated contact may cause mild mechanical irritation due to powder abrasion in solid grades.
  • Eye Contact: May cause mild transient mechanical irritation due to dust particles (solid grades). Direct contact with liquid grades may cause mild transient irritation.
  • Ingestion: Low acute oral toxicity (LD₅₀ > 5,000 mg/kg in rats). Ingestion of large amounts may cause mild gastrointestinal discomfort (diarrhoea, bloating) due to osmotic effects. EO/PO copolymers are not absorbed systemically from the gastrointestinal tract.
• First Aid Measures:
  • Eye Contact: Rinse cautiously with plenty of water for several minutes, removing contact lenses if present and easy to do. If eye irritation persists, seek medical attention.
  • Skin Contact: Wash skin with plenty of soap and water. Remove contaminated clothing. If skin irritation develops, seek medical advice.
  • Inhalation: Move person to fresh air. Keep at rest in a position comfortable for breathing. If symptoms (coughing, throat irritation) persist, seek medical advice.
  • Ingestion: Rinse mouth immediately. Do NOT induce vomiting unless directed by medical personnel. Drink water to dilute if conscious. Seek immediate medical attention if large amount is ingested or if symptoms develop.
• Fire & Explosion Hazards: EO/PO copolymers are not classified as flammable or combustible under normal conditions. However, solid grades may burn if involved in a fire. Accumulated settled dust may form explosive concentrations in air when disturbed and dispersed, as with any organic dust. In case of fire, use water spray, foam, dry powder, or CO₂ as extinguishing media appropriate for the surrounding fire. Thermal decomposition may produce irritating and toxic fumes including carbon monoxide (CO), carbon dioxide (CO₂), and low molecular weight organic compounds.
• Personal Protective Equipment (PPE):
  • Respiratory protection: Use a dust mask (N95 or P2 respirator) if airborne dust concentrations are present or when handling solid powder grades in poorly ventilated areas.
  • Eye protection: Safety goggles or dust‑resistant safety glasses to prevent mechanical eye irritation from dust particles.
  • Skin protection: Chemical‑resistant gloves (nitrile, neoprene) for liquid handling; protective clothing for dust grades to minimise skin contact.
  • General hygiene: Wash hands thoroughly after handling. Do not eat, drink, or smoke in work areas. Minimise dust generation and avoid breathing dust (solid grades).
• Environmental Precautions: EO/PO copolymers are not classified as hazardous to the aquatic environment under most regulatory schemes. Biodegradability varies by EO/PO block length and molecular weight; some grades are readily biodegradable, while higher molecular weight grades may degrade more slowly. Avoid direct release into natural water bodies, drains, or soil in large quantities. Comply with local environmental regulations for disposal.
• Storage & Stability: Store in tightly closed, moisture‑proof containers in a cool, dry, well‑ventilated area away from direct sunlight, heat sources, strong oxidising agents, and strong acids. EO/PO copolymers are hygroscopic (especially high EO grades); protect from atmospheric moisture to prevent caking and lump formation. Solid grades should be stored below 40°C to prevent clumping. Liquid grades should be protected from freezing; if frozen, warm to 25–40°C with gentle agitation to restore flow properties. Under recommended storage conditions (room temperature, low humidity), EO/PO copolymers have a shelf life of 12–24 months (typically 24 months) from date of manufacture in tightly closed original containers.
• Regulatory Compliance: EO/PO block copolymers (Poloxamer, CAS#9003-11-6, EC#225‑208‑0) are listed on EINECS, TSCA, DSL, AICS, NZIoC, ENCS, KECI, PICCS, and other regional chemical inventories. Pharmaceutical grades conform to USP/NF poloxamer monographs (Poloxamer 124, 181, 182, 183, 184, 185, 188, 212, 215, 217, 231, 234, 235, 237, 238, 282, 284, 288, 331, 333, 334, 335, 338, 401, 402, 403, 407) and Ph. Eur. (Poloxamer 188, 407). Food grades are approved as food additives (E1520 in some jurisdictions) and as indirect food additives under FDA 21 CFR for food contact substances. Agricultural grades are approved as inert ingredients under EPA 40 CFR 180.960 for pesticide formulations. The product is regulated as non‑hazardous for transport (UN number not assigned). Always consult the Safety Data Sheet (SDS) and local regulations for complete safety, environmental, and regulatory information specific to each product grade and application jurisdiction.