Polydimethylsiloxane (PDMS)

Overview

Polydimethylsiloxane (PDMS), globally recognized by its INCI name Dimethicone and CAS number 63148-62-9, stands as the most widely utilized silicon-based organic polymer and a cornerstone of modern industrial chemistry. At CanCastor, we understand its pivotal role across diverse sectors. This synthetic polymer, often referred to as silicone oil, is characterized by a flexible backbone of repeating silicon-oxygen units adorned with stable methyl groups. This unique structure imparts exceptional thermal stability, chemical inertness, low surface tension, and hydrophobicity, making PDMS an indispensable additive in countless formulations.

Our comprehensive range of PDMS products is meticulously sourced and manufactured to meet stringent international quality benchmarks, including USP (United States Pharmacopeia), EP (European Pharmacopoeia), JP (Japanese Pharmacopoeia), and BP (British Pharmacopoeia) for pharmaceutical grades, and FDA 21 CFR compliance for food contact applications. CanCastor’s commitment to quality ensures our PDMS products conform to REACH (Registration, Evaluation, Authorisation and Restriction of Chemicals) regulations and are produced under ISO 9001:2015 certified quality management systems. From pharmaceutical compounding to high-performance industrial defoaming, our PDMS delivers consistent, reliable performance demanded by our discerning clientele worldwide.

Key Physical & Chemical Properties

The versatility of Polydimethylsiloxane stems from its remarkable set of properties, which can be tailored by varying molecular weight and viscosity.

• CAS Number: 63148-62-9
• INCI Name: Dimethicone
• Chemical Formula: (CH₃)₃SiO[SiO(CH₃)₂]nSi(CH₃)₃
• Appearance: Clear, colorless, odorless liquid
• Specific Gravity (25°C): 0.963 - 0.970 (e.g., 0.965 g/cm³ for 350 cSt)
• Viscosity (25°C): Available in a wide range, typically 10 cSt to 1,000,000 cSt (Common grades: 100 cSt, 350 cSt, 1000 cSt, 12,500 cSt)
• Refractive Index (25°C): 1.395 - 1.405 (e.g., 1.403 for 350 cSt)
• Flash Point (Closed Cup): >280°C (>536°F) for higher viscosity grades (ASTM D92)
• Pour Point: Typically < -50°C (ASTM D97)
• Surface Tension (25°C): ~20-21 mN/m (dynes/cm), contributing to its excellent defoaming action.
• Solubility: Insoluble in water, methanol, ethanol; soluble in aromatic and aliphatic hydrocarbons, halogenated solvents.
• Thermal Stability: Excellent over a broad temperature range, resisting oxidative degradation.