Polydimethylsiloxane (Low Molecular Weight)
Low molecular weight polydimethylsiloxane (PDMS) oligomers with defined chain lengths are classified as organo-silicon compounds. Under HTS 2931.90.90.10 when chemically defined and not meeting polymer exclusions, distinguished from Chapter 39 silicones.
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Alternative Classifications
This product could be classified differently depending on its characteristics or intended use.
If average molecular weight exceeds polymer threshold
Silicones meeting Chapter 39 polymer definitions (high MW, repetitive units) classify there instead of Chapter 29 compounds.
If lubricating preparations containing silicones
Blends for specific lubrication use shift to Chapter 34 rather than pure compounds.
Not sure which classification is right?
The Tariff Assistant works through the GRI rules on your specific product to reach the right HTS code — and can price the duty on it in the same conversation.
Import Tips & Compliance
• Provide molecular weight distribution and degree of polymerization data to prove chemical definition vs polymer status
• Reference Chapter 29 note (a) for impurities tolerance; >90% purity typically qualifies
Related Products under HTS 2931.90.90.10
Dimethyldichlorosilane
Dimethyldichlorosilane is a chemically defined organo-silicon compound with the formula (CH3)2SiCl2, used primarily as a precursor in silicone polymer production. It falls under HTS 2931.90.90.10 as an organo-inorganic compound where silicon is directly linked to carbon atoms, fitting Chapter 29's scope for separate organic compounds containing nonmetals like silicon.
Trimethylchlorosilane
Trimethylchlorosilane ((CH3)3SiCl) is a volatile organo-silicon reagent used in silylation reactions and silicone synthesis. Classified under HTS 2931.90.90.10 as it meets the definition of organo-inorganic compounds with silicon directly bonded to carbon, excluded from sulfonated/halogenated derivatives.
Vinyltrimethoxysilane
Vinyltrimethoxysilane (CH2=CHSi(OCH3)3) is a coupling agent used in composite materials and adhesives. As a chemically defined organo-silicon compound, it belongs to HTS 2931.90.90.10.
Diphenyldichlorosilane
Diphenyldichlorosilane ((C6H5)2SiCl2) is used in high-temperature silicone resin production. This aryl organo-silicon compound fits HTS 2931.90.90.10 criteria.
Methyltrichlorosilane
Methyltrichlorosilane (CH3SiCl3) is a basic silicone monomer. Classified under HTS 2931.90.90.10 as organo-silicon.
Triethoxysilane
Triethoxysilane (HSi(OC2H5)3) used in silane chemistry. HTS 2931.90.90.10 organo-silicon compound.