mz grade microsphere syntactic foam


ISO 9001:2015 cert

March 8, 2017, Attleboro, MA

Engineered Syntactic Systems (ESS), a global supplier of high-performance syntactic solutions for buoyancy, insulation and composites markets, is pleased to announce the achievement of the ISO 9001:2015 Quality Management Systems Standard Certification. Meeting the rigorous criteria established in the standard, ESS demonstrates and affirms its commitment to consistently deliver quality products and to drive continuous improvement throughout the organization to meet market demands. The certification was authorized by TÜVRheinland®, a premier global provider of independent testing and certification services with 15 locations throughout North America.

Terrence Woldorf, Managing Director, notes, “I am proud to see the validation that comes from having an independent body certify that our controls, processes, communication and commitment are consistent with the ISO 9001:2015 standards. Our management team, employees, processes and business management techniques were scrutinized along with our entire value chain, from initial product design to suppliers through to delivery and customer satisfaction. We passed with flying colors.”

ISO 9001:2015 provides a set of requirements that must be in place to have a quality management system, regardless of the organization’s size, product or service line, or public or private status.

Certification to the standard is voluntary, and organizations must complete a rigorous auditing process by a third-party registrar.

engineered syntactic products

Acoustic Properties of Syntactic Foam – Part 3

Enhanced Density Products

The following measurements were made on our low density syntactic foams:

Depth Rating (meters) Average      Density (Kg/m3) Average

Speed of Sound (m/s)



1000 385 2,186 0.84
2000 400 2,461 0.99
3000 432 2,698 1.17
4000 457 2,767 1.26
4000 515 2,675 1.38
4500 490 2,922 1.43
5000 496 2,968 1.47
6000 552 2,952 1.63
7000 545 3,100 1.69

As noted, even though the hollow glass spheres and resin systems were different, the speed of sound and impedance measurements tracked well with depth rating.

It should be noted that these measurements were made on what we consider to be some of our standard buoyancy products, not materials tailored specifically to provide specific or targeted acoustic properties.  For example, formulations made to Navy specifications have the following properties:

Formulation 1

Density: 690 kg/m3 ± 16

Speed of Sound: 2,850 m/s ± 100

Acoustic Impedance: not specified

Formulation 2

Density: 380 kg/m3 ± 32

Speed of Sound: 2,595 m/s

Acoustic Impedance: 0.940 MRayls

In these instances, specific combinations of resins and microspheres were used to attain the desired properties.  This approach is always an option, though it does require some development and input from the end user.

Properties of CMT Materials Standard Tooling Products

The following measurements were made on our standard plug-assist tooling material (HYTAC®)

Product Name Avg Density (Kg/m3) Avg Speed of Sound (m/s) Impedance


HYTAC-W 690 2,151 1.48
HYTAC-B1X 708 2,568 1.82
HYTAC-C1R 747 2,579 1.93
HYTAC-XTL 755 2,697 2.04
HYTAC-FLX 838 2,749 2.30
HYTAC-WF 838 2,788 2.34
HYTAC-FLXT 897 2,647 2.38
HYTAC-WFT 968 2,700 2.61


While HYTAC materials are not optimized in any way around acoustic properties, the information is interesting nonetheless.  HYTAC-W, for example, is very close to a match for seawater with minimal inconsistencies in terms of density stratification.  As with all of the plug assist tooling products, HYTAC-W is available in a wide range of sizes and shapes.  For example, 2” diameter rods are maintained as a stock item.  This would yield an immediate ~22% savings on material for a given diameter compared to the same amount of material taken from cut blocks if the application required cylindrical shapes.  Sheet sizes starting at one-inch thick up to six-inch thick are also standard, at 0.5-inch increments.  Again, this could mean a significant material savings.

There are several additional observations of note from these test results.  Two sets of the products have derivatives that include polytetrafluoroethylene (PTFE) in syntactic.  (HYTAC-FLX => HYTAC-FLXT and HYTAC-WF => HYTAC-WFT). The PTFE is added to improve the slip at the surface of the material during the thermoforming process and to prevent sticking and material build-up (for more information on thermoforming, visit  The addition of PTFE increases the density but results in a decrease in the speed of sound.  Correspondingly, each material also shows a slight decrease in modulus.  It is also interesting to note the difference we see when making a dramatic change in the matrix material.  There is only a very subtle difference in density between HYTAC-W and HYTAC-B1X, yet the average speed of sound is significantly different due to the change from an epoxy matrix (W) to a thermoplastic matrix (B1X).

In summary, these simple observations illustrate the flexibility available to us as formulators.  The wide range of end-products allows the user to select an off-the-shelf product that may just as easily meet their needs as a complex, unique formulation.

AI-24 syntactic foam

Acoustic Properties of Syntactic Foam – Part 1

One of the great things about syntactic foam is that one can make an almost infinite amount of changes to the types and levels of the constituent materials in order to impart particular properties to the final part.  The types of matrix materials, hollow spheres, additives, and combinations thereof offer materials engineers a wide range of tools to determine end-properties.  Unfortunately, because the possibilities are nearly endless, it is difficult to stop making changes in order to perfect a particular property.  This holds especially true in the area of acoustic properties.  As part of our investigation into the development of products for industries interested in the acoustic properties of syntactic foams, we have discovered a number of interesting areas for exploration.

Acoustic Properties

When we think about acoustic properties, we generally think about whether a material absorbs or reflects sound.  For this discussion, we are thinking about syntactic foam as more of a window that sound waves can pass through.  In very general terms, the degree to which sound is reflected or absorbed by a material is dependent upon the acoustic impedance of the material and the media through which the sound is traveling (in the case of buoyancy materials, this is mainly water).  Other factors, such as wave frequency and incident angle can also play a role, but these are not within our control.  In most cases we are simply trying to match the acoustic impedance of water.  The acoustic impedance of seawater is ~1.50 MRayls[i] and is defined as the speed that sound can travel through the media (~1,450 m/sec) times the density (~1025 kg/m3).  These values will vary depending on things like temperature, water salinity and depth.  Variations can be as great as 10% or more.

Using 1.50 as an initial target, we set out to understand how close we could come with our standard syntactic products.  Measurements were performed on the different types of syntactic foams with a 1 MHz transducer.  Sample densities were also recorded.  Speed of sound and the calculated acoustic impedance in MRayls were reported for each material.  Overall speed of sound was found to be mainly dependent on density but was not independent of the modulus of the matrix material used.  Also, the variation in density through the thickness of the material was found to be very important.

In the next installment, we discuss comparative testing and data for multiple syntactic materials.

[i] MRayl, or Rayleigh, is a unit of measure used to describe characteristic acoustic impedance.

Subway ventilation panels

Engineered Syntactic Foam as Structural Material

Syntactic foams have long been used as buoyancy materials in subsea applications due to their extremely high hydrostatic strength and stiffness at relatively low densities.  This unique combination provides designers a source of lift for vehicles and structures operating in the deepest ocean environments.  Manned submarines, AUVs (Autonomous Underwater Vehicles) and ROVs (Remotely Operated Vehicles) all rely on syntactic foam in performance of their missions.

There are many other applications where the distinct properties of syntactic foam have also been employed.   Syntactics are excellent as low-to-moderate weight core materials for composite structures. The cellular structure of the material also makes them excellent thermal insulators, especially in situations where high strength may be required. Syntactic materials are utilized in transducers because the dielectric properties remain constant at depth.    As with most highly filled substances, the material is also dimensionally stable over a wide temperature range making it an ideal candidate as tooling for polymer or composite processing.

Challenging environments in the building and construction sectors are also areas where syntactic foam is now being used.  For example, syntactics are well-suited to the specific requirements of subway emergency ventilation panels.  Such panels must perform structurally but also be lightweight for ease of installation.  With the same strength as concrete at 20% of the weight, syntactic panels are cost-effective and highly efficient. The panel material must also be non-corrosive and resistant to water absorption over its lifetime.   Two additional properties are critical in this environment.  First, because the panels are used in an enclosed environment with direct human access, the material must pass stringent fire standards, most unusual for a product typically found hundreds or thousands of meters below the ocean surface.   Second, the need for clear radio communication in emergency tunnels is paramount for safety.  RF communication signal loss has been specified at less than 1.5 db over a wide frequency range. Syntactic panels are radio frequency wave transparent, thus meeting signal loss criteria.

We have been working on Low Flame, Smoke and Toxicity (LFST) products for use in civil infrastructure applications with new materials that have been tested and approved using ASTM methodology. Click here to see our time-elapsed video or get in touch with us to discuss your specific application.