PIR foam — physical and processing properties
Biocongruent additives were incorporated into a rigid PIR foam based on a polyester polyol and compared against the unmodified control. Yield stress, yield load, density and the full reaction profile stayed within the control’s range.
| System | Yield stress @ 10% (psi) | Yield load (lb) | Density (lb/ft³) | Gel | Rise | Tack free |
|---|---|---|---|---|---|---|
| 100% fossil-based polyester polyol | 39.0 (±1.7) | 155.9 (±6.0) | 2.30 (±0.02) | 1m | 2m | 4m |
| + 5 part TCPP | 38.7 (±1.2) | 152.6 (±4.3) | 2.29 (±0.02) | 1m | 2m | 4m |
| 15 part soy-additive (B) | — | 145.1 (±5.1) | 2.28 (±0.03) | 55s | 2m | 3m 50s |
| 15 part lignin-additive (C) | 35.5 (±2.8) | 140.7 (±6.1) | 2.29 (±0.03) | 1m 5s | 2m 5s | 3m 15s |
Values as reported at CPI 2026. Actual performance depends on your formulation.
PIR foam — flame performance against TCPP
The phosphorylated soy-additive outperformed a conventional halogenated flame-retardant additive on mass loss and flame spread rate at the levels tested.
| System | Mass loss (g) | Mass loss (%) | Flame spread rate (cm/s) |
|---|---|---|---|
| 100% fossil-based polyester polyol | 0.85 (±0.12) | 8.4 (±1.1) | — |
| + 5 part TCPP | — | 5.0 (±0.2) | 0.31 (±0.03) |
| 15 part soy-additive (B) | 0.30 (±0.05) | 3.0 (±0.1) | 0.23 (±0.03) |
Elastomer carpet backing — Class I flame rating matched
A blend of soy-additive with a phosphate flame retardant replaced 20 parts of polyol and filler in a non-cellular PU carpet backing. The result matched a commercial Class I rated carpet.
| Sample | Flame distance (cm) | Flame out time | Flame spread rate (cm/s) |
|---|---|---|---|
| Control (100% fossil-based polyol) | 9.27 (±0.8) | 5m 36s (±25s) | — |
| 20 part replaced (soy-additive + phosphate FR) | — | 3m 4s (±20s) | 0.015 |
| Commercial Class I carpet | 2.54 (±0.1) | 2m 32s (±23s) | 0.017 |
Soil burial — rigid PIR foam
Mass loss under soil burial, in percent, over 28 days. Both biocongruent additives increased degradation rate against the fossil-based control.
| Day | Control | 100% soy-additive | 40% soy-additive | 40% lignin-additive |
|---|---|---|---|---|
| 0 | 0 | 0 | 0 | 0 |
| 7 | 1.8 | 8.5 | 3.3 | 6.7 |
| 14 | 3.4 | 13.2 | 6.7 | 8.4 |
| 21 | 4.9 | 14.9 | 10.0 | 10.0 |
| 28 | 6.8 | 18.1 | 12.9 | 11.4 |
Mass loss (%) under soil burial.
Soil burial — viscoelastic foam
| Day | Control | 30% soy-additive | 50% soy-additive |
|---|---|---|---|
| 7 | 2.8 | 4.8 | 5.4 |
| 14 | 6.1 | 8.8 | 10.0 |
| 21 | 7.7 | 10.5 | 14.1 |
| 28 | 11.3 | 14.7 | 17.3 |
| 35 | 12.7 | 18.0 | 21.3 |
| 42 | 14.8 | 20.0 | 22.6 |
| 49 | 15.3 | 21.3 | 26.0 |
Mass loss (%) under soil burial.
Wastewater exposure — non-cellular elastomer
Samples were held under LA Green Book sewer conditions of roughly 800 mg/L biological oxygen demand — common wastewaters run around 300 mg/L — as an example of anaerobic biodegradation. Mass loss progressed steadily while tensile strength was retained.
| Time (days) | Mass loss (mg) | Tensile (psi) |
|---|---|---|
| 0 | 0.5 | 900 |
| 28 | 26.7 | 1000 |
| 112 | 50.3 | 900 |
Cradle-to-grave LCA — silicone versus EPDM heater hose
A comparative attributional ISO 14040/14044 assessment focused on carbon footprint and cumulative energy demand, with primary manufacturing data supplemented by secondary life cycle inventory datasets and landfill disposal assumed for both hoses.
- Product carbon footprint of the EPDM and silicone hoses is about the same per unit.
- Silicone heater hose delivers roughly three times the service durability in vehicles, so the adjusted carbon footprint of EPDM is larger per functional unit.
- A chemical hydrolysis pathway exists for breakdown of silicone when landfilled; no equivalent pathway exists for EPDM.
Attribution
“Biocongruent Chemistry” — Saeed Fosshat, Katie Soulliere, Enoch K. Acquah, Xian Xian Du, Andrew H. Garrett and Thomas M. Garrett. MCPU Polymer Engineering LLC (Pittsburg, KS), LCA Design Corporation (Windsor, ON) and Purosil LLC (Corona, CA). Presented at the CPI 2026 Polyurethanes Technical Conference, Orlando, FL.