Polydimethylsiloxane (PDMS)

🛢️ 1. Lubricant & Industrial Oil Antifoam Additive

Foam in lubricating oils - caused by mechanical agitation, air entrainment, or surfactant contamination - leads to reduced film thickness, increased wear, cavitation damage, and oxidative degradation. PDMS is the standard antifoam additive in engine oils, gear oils, hydraulic fluids, compressor oils, and turbine oils, typically used at treat rates of 10–100 ppm. Its extremely low surface tension (∼21 mN/m) allows it to rapidly spread at the oil-air interface and collapse foam bubbles before they cause damage. PDMS is compatible with all common lubricant additive packages - anti-wear agents, antioxidants, detergents, and dispersants - without adverse interaction. China suppliers offer PDMS grades optimized for both mineral oil and synthetic (PAO, ester) base oil systems.

🏗️ 2. Industrial & Chemical Process Defoamer

Foam control is a critical process parameter in fermentation, wastewater treatment, paints and coatings, adhesives, textile dyeing, pulp and paper, and petrochemical refining. PDMS-based defoamers are the industry's first choice for these applications due to their effectiveness across a wide pH range (2–13), long-lasting performance, and thermal stability up to 200°C. In oil and gas production, PDMS is used in separation vessels, gas scrubbers, and amine sweetening units to control process foam and protect downstream equipment. Emulsified PDMS formulations (PDMS in water or solvent) are available for water-based systems where direct addition of neat silicone oil is not practical.

🍽️ 3. Food Processing Antifoam (Food Grade, E900)

Food-grade PDMS (listed as E900 in Europe; regulated under 21 CFR §173.340 in the USA) is widely used to prevent foam formation in cooking oils, beverages, dairy processing, fermentation (beer, wine), sauces and condiments, and baking. It is approved by FDA, EFSA, and JECFA for direct food contact applications with an ADI of 0–1.5 mg/kg body weight. Typical use levels are 1–10 ppm in food systems. Sinolook supplies NSF/food-grade certified PDMS for buyers in the food and beverage industry requiring full regulatory documentation.

💄 4. Personal Care, Cosmetics & Pharmaceutical

Low-viscosity PDMS (50–350 cSt) is a key ingredient in shampoos, conditioners, skin creams, sunscreens, and medical device coatings. Its biocompatibility, physiological inertness, and non-comedogenic properties make it an ideal skin-conditioning and anti-foaming agent in cosmetic formulations. In pharmaceuticals, it is used as a gastrointestinal antifoam in anti-bloating medications (simethicone). In the automotive and electronics industries, PDMS serves as a mold release agent, sealant, damping fluid, and dielectric coating - one of the most versatile industrial chemicals available.

PDMS is typically supplied in 200 L drums or IBC totes (1,000 L). High-viscosity grades (≥ 60,000 cSt) may require heated storage and transfer equipment - confirm your handling capability before ordering. For lubricant antifoam applications, always dose PDMS at the lowest effective treat rate (start at 10 ppm and increase as needed) - over-dosing can cause air entrainment in some base oil systems. Request a free sample for bench-top treat-rate optimization before committing to bulk quantities.

Q1: What is the CAS number for Polydimethylsiloxane (PDMS)?

The primary CAS number is 9006-65-9 for the linear polydimethylsiloxane polymer. Related CAS numbers include 63148-62-9 (dimethicone) and 107-46-0 (hexamethyldisiloxane, a very short-chain variant). Please specify the required viscosity grade and intended application (lubricant, food, personal care, industrial) when requesting a quotation.

Q2: What is the difference between PDMS antifoam and hydrocarbon-based defoamers?

PDMS offers three key advantages over hydrocarbon defoamers: (1) significantly lower treat rates - effective at 10–100 ppm vs. 500–2,000 ppm for hydrocarbons; (2) wider temperature stability - effective from -50°C to +200°C vs. narrower range for hydrocarbons; and (3) broader chemical compatibility - effective across pH 2–13 and compatible with most chemical systems. The trade-off is higher unit cost, but this is typically offset by the much lower treat rate required.

Q3: Is food-grade PDMS (E900) safe? What are the regulatory approvals?

Yes. Food-grade PDMS (E900) is approved by FDA (21 CFR §173.340), EFSA (E900), and JECFA (ADI 0–1.5 mg/kg bw) for use as an antifoaming agent in food processing. It is not absorbed through the gastrointestinal tract and is excreted unchanged. No carcinogenic, teratogenic, or genotoxic effects have been identified in regulatory studies. Sinolook can supply food-grade PDMS with full regulatory compliance documentation including CoA, SDS, and certificate of food-grade conformity.

Q4: Which PDMS viscosity grade should I use as a lubricant antifoam additive?

For lubricant antifoam applications, 350–1,000 cSt grades are most commonly used in engine oils, gear oils, and hydraulic fluids. Higher viscosity grades (5,000–12,500 cSt) provide more persistent foam suppression in heavily loaded industrial gear oils and oil-and-gas systems. For synthetic (PAO/ester) base oil lubricants, lower viscosity grades (50–200 cSt) are preferred for better dispersion. Our technical team can provide treat-rate recommendations for your specific formulation.

Q5: What documentation is available for import and quality verification?

Sinolook provides a complete documentation package: Certificate of Analysis (CoA), Safety Data Sheet (SDS/MSDS), commercial invoice, packing list, Bill of Lading, and Certificate of Origin. For food-grade orders: FDA/E900 compliance letters and NSF documentation. Third-party inspection reports (SGS, Intertek, BV) and REACH registration documentation are available upon request.