ZG-STMOS Mono-End Trimethoxy-Functional Polydimethylsiloxane
ZG-STMOS contains a hydrolyzable trimethoxysilane group at one end of the molecule, with the other end being a non-reactive capping group. The terminal -Si(OCH₃)₃ can hydrolyze in the presence of moisture to form silanol and further self-condense; under suitable conditions, it can also undergo condensation bonding with hydroxyl groups on the surface of glass, silica, metal oxides and inorganic fillers. After reactive anchoring, PDMS segments can impart a certain degree of hydrophobicity, low surface energy, flexibility and lubricity to the surface, and help improve the wetting, dispersion and filling flowability of inorganic powders in resins. This mono-end structure is better suited to surface/interface modification and reactive anchoring; for network crosslinking, it is recommended to use it together with a base moisture-curing resin or multifunctional crosslinking components.
Product positioning: mono-end moisture-reactive silicone interface modifier for introducing PDMS flexible hydrophobic segments in inorganic powder/filler surface treatment, interfacial anchoring, moisture curing and highly filled thermally conductive systems
Chemical Type
Mono-end trimethoxysilane-terminated PDMS
Functional Structure
Mono-end -Si(OCH₃)₃; the other end non-reactive capping
Reaction Type
Hydrolysis-condensation; surface hydroxyl condensation/moisture reaction
Product Form
Colorless transparent liquid
Product Features
Moisture-Reactive End Group
The terminal trimethoxysilane group can hydrolyze under controlled conditions to form silanol, and through condensation achieve surface anchoring, interface modification or participation in moisture reactions
Powder and Interface Modification
Helps reduce the surface energy of inorganic particles and improve the wetting, dispersion and high-fill processing flowability of powders in polymer resins
PDMS Surface Effect
After reactive incorporation, provides a certain degree of hydrophobicity, low surface energy, flexibility, slip and moisture resistance, and helps reduce free siloxane migration
Selectable Molecular Weight
1500/2000 emphasize higher methoxy density, low viscosity and interfacial reaction efficiency; 2500 is a balanced type; 6000 emphasizes longer PDMS segments and surface effects, requiring focused verification of spreading and compatibility
Typical Technical Specifications
| Model | Nominal Mn (g/mol) | Appearance | Viscosity (25°C, mPa·s) | Methoxy Equivalent (g/eq) | Methoxy Content (mmol/g) |
|---|---|---|---|---|---|
| ZG-STMOS-1500 | 1500 | Colorless transparent | 14.5 | 500 | 2.00 |
| ZG-STMOS-2000 | 2000 | Colorless transparent | 27 | 704 | 1.42 |
| ZG-STMOS-2500 | 2500 | Colorless transparent | 33 | 840 | 1.19 |
| ZG-STMOS-3000 | 3000 | Colorless transparent | 15-30 | 1000 | 1.00 |
| ZG-STMOS-6000 | 6000 | Colorless transparent | 76 | 1961 | 0.51 |
*Nominal Mn is a grade reference; the actual batch is subject to the COA.
Applications
| Application System | Recommended Dosage (Engineering Starting Range) |
|---|---|
| Inorganic Powder/Thermally Conductive Filler Surface Treatment | 0.3%-2.0% of powder mass |
| Glass, Silica and Metal Oxide Surface Modification | 0.5%-3.0% in the treatment liquid |
| Moisture-Curing Sealants/Modified Silicones | 1.0%-10.0% of the base rubber or resin solids |
| Interface Modification of Coatings, Adhesives and Composites | 0.5%-3.0% of resin solids |
Compatibility and Solubility
| Category | Notes |
|---|---|
| Generally easy to mix | Low-polarity media such as toluene, xylene and low-viscosity siloxanes; actual dissolution and compatibility vary with PDMS molecular weight and medium composition |
| Requires lab-trial confirmation | Mineral spirits, acetates, PMA, MEK/MIBK, alcohols and various resin systems; alcohol/water content affects the hydrolysis and stability of the trimethoxy end group |
| Not recommended for direct addition | Aqueous phases or high-water-content systems. If hydrolysis treatment is used, water should be added in a controlled manner per the established process and used immediately upon preparation to avoid pre-condensation during storage |
| Selection principle | 1500/2000 are preferred for low-viscosity operation, powder wetting and higher end-group density; 2500 is a comprehensive balanced type; 6000 is better suited to formulations requiring longer PDMS segments, flexibility and hydrophobic surface effects |
Reaction and Formulation Notes
Mono-end trimethoxy structure:One chain end carries -Si(OCH₃)₃, which after hydrolysis can form multiple silanol reactive sites and undergo surface condensation or self-condensation; its main advantage lies in interfacial anchoring and surface functionalization, and it should not be simply equated with a double-end or multifunctional polymer crosslinker
Powder treatment dosage:The optimal dosage is closely related to specific surface area, surface hydroxyl density, particle size and target coverage. Too low a dosage may result in insufficient coverage; too high a dosage may cause free siloxane, powder agglomeration or reduced resin compatibility
Hydrolysis safety note:Hydrolysis of the trimethoxysilane end group generates methanol. Good ventilation should be maintained during use and personal protection taken per the MSDS; catalytic systems such as acids, bases and tin/titanium can significantly change the hydrolysis-condensation rate and must be determined through lab trials
Packaging, Storage and Safety
Packaging:25 kg, 50 kg, 200 kg plastic drums
Storage:Keep containers sealed and store in a cool, dry, ventilated place at 5-35°C, strictly moisture-proof and away from direct sunlight, acids, bases and catalysts that can promote hydrolysis-condensation
Shelf Life:Recommended shelf life of 12 months in unopened conditions
Safety Notes:For transport, handling and personal protection requirements, refer to the corresponding MSDS and local regulations