Styrene Monomer (Crosslinking Grade, 99.5%)
CAS 100-42-5Styrene Monomer (vinylbenzene, CAS 100-42-5) crosslinking grade at 99.
Key Features
- ✓Reactive diluent AND crosslinker — becomes part of cured UPR/VER network (not a true solvent)
- ✓Standard viscosity reducer for UPR: 30–45% styrene is typical in commercial resin
- ✓Supplied with TBC inhibitor for storage stability — monitor inhibitor level during storage
- ✓IARC Group 2A suspected carcinogen — requires workplace air monitoring and PPE
- ✓Regulated VOC: driving force behind low-styrene and styrene-free UPR development
Specifications
| Parameter | Value |
|---|---|
| Purity | ≥99.5% by GC |
| Appearance | Clear, colorless liquid |
| CAS Number | 100-42-5 |
| Flash point | 31°C (ASTM D93) |
| Boiling point | 145°C |
| Water content | < 0.05% |
| Density (20°C) | 0.906 g/cm³ |
| Inhibitor (TBC) | 10–15 ppm |
FAQ
Yes, this is a common and accepted practice. Adding 3–8% styrene monomer by weight to a standard gelcoat resin reduces viscosity by 100–300 mPa·s, bringing a thick, brush-grade gelcoat into the spray viscosity range (800–1500 mPa·s for airless spray; 500–900 mPa·s for conventional air spray). Styrene addition at this level does not significantly affect gel time, color, or cured gelcoat properties — the added styrene participates in the cure normally. However, adding excessive styrene (>10%) can reduce crosslink density and Barcol hardness of the cured gelcoat, and increases VOC emissions. Always measure gelcoat viscosity with a Zahn cup or rotational viscometer at working temperature before adjustment, and verify gel time after styrene addition to compensate with peroxide and accelerator if needed.