Polysuccinimide
CAS 31586-29-5 (C4H3NO2)n
- CAS number
- 31586-29-5
- Formula
- (C4H3NO2)n
- Molar mass
- 97.07 g/mol repeat unit · polymer MW ~1,000–10,000 (up to ~50,000)
Supply of Polysuccinimide
- Grades
- Water-treatment and cosmetic grades are defined by molecular weight and appearance rather than a single assay figure.
- Packaging
- 25 kg fiber drums/bags · 500–1000 kg bulk bags
- Documents
- CoA, SDS and TDS on request; certificate of origin where the destination requires it.
- Delivery
- Worldwide, including the United States, Canada, the United Kingdom, Germany and the rest of the EU, the United Arab Emirates, India, Singapore, Malaysia and Australia. Quoted EXW, FOB, CIF or DAP.
Polysuccinimide is a light brown powder used to make water-treatment chemicals. Mixed with an alkali, it turns into polyaspartate, a biodegradable ingredient that stops limescale from building up in boilers, cooling towers and pipes, and that is also used in some detergents. It is shipped as a dry powder because that is cheaper than shipping the finished liquid.
Technical details
Polysuccinimide is the anhydrous polyimide that sits one step upstream of polyaspartate. On its own it is a beige, water-insoluble powder with little direct application; hydrolyse it with alkali and it opens into sodium polyaspartate, a biodegradable polycarboxylate that sequesters calcium and disperses scale. PSI is traded because of that two-stage route: it ships and stores as a dry solid rather than as a dilute polymer solution. Ehlinar supplies water-treatment and cosmetic grades, defined by molecular weight; the polymer carries more than one registered CAS number.
Appearance: Beige to light-brown powder; virtually water-insoluble; slowly hydrolyses to polyaspartate.
Applications
How we supply
- Certificate of Analysis (CoA), lot-specific where available
- Safety Data Sheet (SDS / MSDS)
- Technical Data Sheet (TDS)
- Certificate of Origin / Certificate of Conformity
Independent third-party inspection can be arranged on request, with the agency and scope agreed per trade. Representative samples can be requested for qualification, subject to supplier availability. We recommend incoming quality control against the agreed CoA.
Quoted on standard Incoterms (e.g. EXW, FOB, CIF, DAP) as agreed per trade. Delivery region, packaging and grade are confirmed per quote.
Documents and services above are subject to supplier availability and confirmed per quote; nothing here is an offer.
Typical / indicative values — not a binding specification
| Property | Typical |
|---|---|
| Molecular weight | ~1,000–10,000 (up to ~50,000) |
| Repeat-unit mass | 97.07 g/mol |
| Water solubility | Virtually insoluble — hydrolyses to polyaspartate |
Also known as
PSI · Anhydropolyaspartic acid · Poly[imino(1-oxo-1,2-ethanediyl)] · Polyaspartic-acid (PASP) precursor
Frequently asked questions
- Is polysuccinimide water-soluble?
- No — it is essentially water-insoluble. For aqueous use it is hydrolysed to sodium polyaspartate.
- Is it biodegradable?
- Yes, via its polyaspartate derivative, which is why it is used as a greener alternative to some phosphonates and polyacrylates.
- Why does PSI have several CAS numbers?
- It is registered variably by molecular weight and synthesis route, so the exact CAS and molecular weight depend on the grade.
- How is polysuccinimide converted to polyaspartate?
- By alkaline hydrolysis. Published routes add sodium hydroxide to a PSI slurry and hold it warm, typically somewhere between 65 and 90 °C at alkaline pH, until the imide rings open to the sodium polyaspartate salt. Conditions vary with the molecular weight and the colour specification being targeted.
- Why buy PSI rather than polyaspartate directly?
- Mostly logistics. PSI is a dry powder, so you are not shipping and storing water; polyaspartate is normally sold as an aqueous solution. Formulators who hydrolyse in-house can also set the degree of conversion and the counter-ion themselves.
Enquire about Polysuccinimide
Related products
Figures and identifiers here are compiled from public references and provided for general information; they are indicative, not a specification. See all products.