Soy-Based PU Foam Characterization

Abstract

Understanding the magnitude and mechanisms of the soy based polyurethane (PU) foams and properties of materials has implications on the application of this foams. Insulators protect devices from aggressive heat. However, due to the highly porous nature of the foams and the increase in interfaces due to fillers such as kenaf core, helps increase mechanical properties, while maintaining the light density of the foam. The effect of fillers on is a critical parameter in investigating the thermal properties and its effect on biodegradability. In this paper, we use thermal conductivity, compression values, and scanning electron microscopy (SEM) to understand the phenomena behind these results. Additionally a compostability test was performed to determine degradation under standard composting conditions.

Keywords: thermal conductivity, MTS, Soy based PU, compostability, SEM

Introduction

The need for alternative foam products has become a priority in several fronts; foams are present in two main areas, food packing and insulations, with outstanding performance, low density and high thermal insulation makes them perfect, but both applications have a very short life cycle and then an undesirable recyclability or biodegradability.

Polyurethane (PU) is one of the most versatile and intensively used industrial materials. By the proper selection of reactants and changing percentage of the component in the formula, the resulting polyurethane can be elastomer, thermoplastic, thermosetting, rigid and flexible foams. Rigid polyurethane foams can be used as construction materials, such as polymeric concrete components, insulating materials, sealants and signboard. One of the major components to make polyurethane, polyol, is largely relying on petroleum crude oils and coals as feedstock. However, bio-based polyols have been developed from vegetable oils such as soybean oil, canola oil, palm oil and castor oil, due to the environmental and sustainable issues in recent years ((Bergeret 2011), (Calmon 2000), (Dřímal 2007), (Faruk 2012)) [1-5]. Developing bio-renewable feedstock for industry is crucial now for both the economic and environmental reasons.

Soybean oil is an annually renewable natural resource for the polyols and is available in large quantities. For each pound of soybean oil produced, 2.67 pounds of carbon dioxide are removed from the air [1]. Soy-based polyols can be used in various polyurethane applications by selecting proper functional groups and side chains. Polyurethanes produced from soy-based polyols normally exhibit equivalent or improved physical and chemical properties due to the hydrophobic nature of triglycerides.

The selection of the Kenaf core is due to the great availability, representing more than 60% of the Kenaf plant, and not being as desired as the fiber portion of the plant that has a higher demand, the core also has a particular property that make it more desirable on foams, it is hydrophobic, composites has increased the global demand for natural fiber crops. Kenaf is an annual species of fiber crop which can grow to around 9 feet in 9 months.

When Composting PU together with other biomass waste, the biodegradation process can happen within two weeks and the materials will be fully decomposed, having disappeared within three to four weeks. Since the introduction of the Soy base PU, we decided to verify the industrial compost ability of the foams and its rate. A final verification was needed to determine the degree of toxicity in the remaining compost, Phytotoxicity, a detrimental deviation from the normal pattern of appearance and growth of plants in response to a given substance, is designed to assess potential effects of substances on seedling emergence and growth. As such it does not cover chronic effects or effects on reproduction. Passing this test is without doubts a major indicator of the compost suitability of final our product at the end of the life cycle (Test No. 208: Terrest...).

The main objective of this research was to develop soy-based polyurethane foam reinforced with Kenaf core and to investigate thermal properties, furthermore, the effect of Kenaf core addiction when foaming the composite, the standardized compostability capacity of the foam in the whole spectrum of samples and a final phytotoxicity test to proof a safe waste at the end of the life cycle.

The main objective of this research was to develop soy-based polyurethane foam reinforced with multi-walled carbon nanotubes to enhance the compressive and mechanical properties. Soy-based polyurethane / carbon nanotubes composites with loadings of 0.5 and 1.0 wt% were synthesized. The effects of kenaf content on the properties of soy-based polyurethane foam composites were investigated.