Trelleborg - An Introduction to Syntactic Foam

Summary

Ben O'Sullivan, Materials Technology Team Manager at Trellborg Offshore, provides an in-depth introduction to syntactic foams. He explains the composition, types (pure and composite), and the materials used in creating syntactic foam, highlighting its role in subsea operations. Syntactic foam is primarily used to provide buoyancy for heavy subsea structures, such as pipelines and drill risers. The video also covers the key properties of syntactic foam, including hydrostatic strength, ball modulus, water absorption, and hydrostatic creep. Finally, O'Sullivan outlines the rigorous testing methods employed at Trellborg Offshore to ensure long-term performance and reliability.

Takeaways

• 😀 Syntactic foam is a lightweight, high-strength material created by mixing hollow spheres with a resin matrix to form a composite with voids.
• 😀 The term 'syntactic' refers to the combination of hollow spheres within the resin matrix, while 'foam' highlights the cellular nature of the composite.
• 😀 There are two types of syntactic foam: pure syntactic foam, made from hollow spheres and polymer binders, and composite syntactic foam, which includes larger macrospheres to further reduce density.
• 😀 Hollow glass microspheres (HGMs) are commonly used in syntactic foam, providing low density (120 to 600 kg/m³) and high strength, which is critical for subsea applications.
• 😀 The polymer binder used in syntactic foam can be either thermoset (e.g., epoxy, polyurethanes) or thermoplastic, depending on the specific application.
• 😀 Composite syntactic foam uses macrospheres, which can be thermoplastic or thermoset, to decrease density and provide additional buoyancy, ideal for subsea structures.
• 😀 Syntactic foam’s primary application at Trellborg Offshore is for buoyancy, especially for subsea structures like pipelines and drilling risers, to provide upthrust and maintain proper configuration.
• 😀 The material’s key properties for subsea applications include hydrostatic strength, ball modulus (stiffness), hydrostatic creep (long-term deformation), and low water absorption.
• 😀 Testing methods for syntactic foam include the Hydrostatic Crush Pressure (HCP) test, which measures short-term strength, and the Instrumented Buoyancy Loss (IBL) test, which assesses long-term performance and buoyancy loss.
• 😀 The strength-to-weight ratio of syntactic foam is crucial for reducing the weight of subsea structures, with the ultimate goal being the highest possible ratio for improved buoyancy and performance.

Q & A

What is syntactic foam, and what is it made from?

Syntactic foam is a lightweight, high-strength material created by combining hollow glass microspheres with a resin matrix. This composite material contains voids, and the hollow spheres give it its unique properties, such as low density and high strength.

What does the word 'syntactic' mean in the context of syntactic foam?

The word 'syntactic' comes from the Greek word 'syntax,' which means 'the combination of order.' This refers to the organized arrangement of hollow spheres within the resin matrix of the foam.

What is the difference between pure syntactic foam and composite syntactic foam?

Pure syntactic foam is made by combining hollow glass microspheres with a polymer binder, while composite syntactic foam includes larger hollow spheres called macrospheres, which further reduce the density of the material.

What materials are used to create hollow glass microspheres (HGMs) in syntactic foam?

Hollow glass microspheres (HGMs) are typically made from borosilicate glass. These microspheres vary in size and density depending on their application, with typical diameters under 120 microns.

Why are glass microspheres commonly used in syntactic foam?

Glass microspheres are used because they are lightweight, strong, and provide the necessary buoyancy for subsea applications. Their properties make them ideal for creating syntactic foam with a high strength-to-weight ratio.

What is the role of the polymer binder in syntactic foam?

The polymer binder, or resin matrix, holds the hollow glass microspheres together and provides structural integrity to the foam. Depending on the application, different types of polymers, such as thermoset or thermoplastic polymers, are used.

What are macrospheres, and how do they differ from microspheres?

Macrospheres are larger hollow spheres used in composite syntactic foam to further reduce the material's density. Unlike microspheres, which are very small, macrospheres are designed to add more buoyancy and are available in diameters from 5 mm to 40 mm.

What types of polymer systems are used for syntactic foam?

Syntactic foam can use either thermoset or thermoplastic polymers. Thermoset polymers, such as epoxy resins, create permanent bonds and a cross-linked matrix, while thermoplastic polymers can be remelted and molded multiple times.

Why is syntactic foam crucial for offshore applications?

Syntactic foam is essential for providing buoyancy to heavy subsea structures, such as pipelines and drilling risers, helping them maintain their position underwater. It ensures that these structures remain stable and provide support at various depths.

What are the key properties of syntactic foam that are monitored for quality control?

The key properties include hydrostatic strength (pressure resistance), bull modulus (material stiffness), water absorption (effect on buoyancy), and hydrostatic creep (long-term contraction under load). These properties are critical to ensuring syntactic foam performs well in deep-sea conditions.