# Bio-Based Viscoelastic Polyurethane Foams: Functional Behavior Across Application Temperatures

## TL;DR

Bio-based polyurethane foams made from natural oils show good viscoelastic properties at room and higher temperatures but become stiffer in colder conditions.

## Contribution

The study evaluates the functional behavior of bio-based polyurethane foams across application temperatures using different bio-polyol sources.

## Key findings

- Foams with coconut oil and duck fat polyols showed enhanced energy absorption.
- Bio-based foams maintained suitable viscoelastic properties at 20 and 40 °C for furniture use.
- Low-temperature performance was limited by increased stiffness below 10 °C.

## Abstract

Viscoelastic polyurethane foams were prepared using four different bio-based polyols derived from coconut oil (CO), palm oil (PO), duck fat (DF), and pork fat (PF), employing up to 20 wt.% of the polyol component in a conventional formulation. The introduction of bio-polyols into the polyurethane formulation gave rise to an early minor decomposition of modified foams at low temperatures; however, the overall thermal stability improved slightly by the elimination of some intermediate decomposition stages. The glass transition temperature of foams was only moderately influenced and remained in the typical temperature range (around 10 °C). The effect of biopolyol type and content (5–20 wt.%) on the mechanical properties of the foams was investigated over the temperature range −20 to 40 °C. At 20 and 40 °C, all foams exhibited comfortable viscoelastic properties suitable for furniture applications. Hysteresis and the damping behavior of foams were also influenced by biopolyol type and concentration, with CO and DF providing enhanced energy absorption. Overall, these bio-based foams demonstrate potential for eco-friendly, high-performance applications, although their use at temperatures below 10 °C may be limited by increased stiffness.