Scientists have developed a biodegradable water-soluble 3D printing support material

- Nov 14, 2019-

A team of researchers has developed a new material that could be used as a universal water-soluble carrier for additive manufacturing (3D printing).

Its thermal stability and firm adhesion make it an ideal support system for a variety of building materials.


Most manufacturers understand how 3D printing enables them to produce stronger, lighter parts and systems.

Although many different materials can be used to create 3D printed models, the most commonly used are thermoplastics, such as acrylonitrile butadiene styrene (ABS), polylactic acid (PLA) and polycarbonate (PC).

Complex thermoplastic components and structures with Bridges or overhangs require support during printing.

Because these support structures are not part of the model, they need to be removed after printing.

The subsequent processing step is important because it affects the final surface finish, strength and color of the printed part.

And sometimes harmful chemicals are needed to damage the surface of the model and reduce productivity.

Therefore, choosing the right materials for 3D printing support structures is crucial.


BREAKVS soluble support structure


There are two basic types of materials available for supporting structures: separable and soluble.

Separation support structures are usually constructed from materials similar to printed objects.

After printing, support can be removed by trimming, mechanical fracture or wear.

All of these steps add effort, and therefore time and cost.

In addition, removing the 3D printed support structure may leave defects on the model's surface or destroy the model with the structure.

In addition, separation support is often more difficult to remove when using high-temperature materials.


Soluble support development challenges


Developing water-soluble carriers is challenging.

First, a limited number of commercially available resins that are truly water soluble.

Many water-soluble polymers are brittle, which prevents them from turning into filaments.

In addition, plasticizing with traditional additives typically inhibits thermal stability and adhesion, severely limiting their use in 3D printing.


The first generation of soluble carriers had many problems.

Some use harmful chemicals or strong acidic or alkaline solutions.

Although some of these are still widely used, resin technology has developed and there are now a large number of soluble support materials on the commercial market, including:


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• highly proprietary resins (Stratasys SR30, SR35, SR100, etc.)


• resin based on commonly used PVA or polyvinylpyrrolidone (PVP)


• cellulose, such as hydroxypropyl methyl cellulose (HPMC)


• foreign polybutanediol vinyl alcohol (BVOH)


However, none of these products are ideal for filaments as they are not thermally stable.

Now there is a better choice of materials.


Water soluble resin sufficient to dissolve filaments


Infinite Material Solutions has recently developed a composite Material that is both water soluble and thermally stable.

The "out of the box" resin is made by mixing natural carbohydrates with a soft, tough and water-soluble polymer.

The new material (branded AquaSys™120) is unique because it is strong enough to be used as a support wire.

This recipe is surprising because many pure carbohydrates and water-soluble polymers are too brittle to form usable filaments.

Over the years, formula designers have made numerous attempts to plasticize water-soluble resins in order to convert them into filament.

However, the addition of plasticizers usually significantly reduces the thermal stability of the base resin.

In addition, plasticizers inhibit adhesion between materials, severely limiting their use in 3D printing.

AquaSys 120 USES a highly complex process to produce filaments in 1.75mm and 2.85mm diameters that can be successfully used on a variety of 3D printing platforms and materials.


Benefits and compatibility of materials


The components of the new material have been used in a wide range of industrial applications, from packaging and drug delivery to cosmetics and personal care products.

According to information available for all individual components, the material is hydrophilic, biocompatible, biodegradable, non-toxic and carcinogenic.


The new filament material can be used in the most common 3D printing technologies, including molten filament manufacturing and direct material extrusion.

It is also compatible with a variety of materials, including polypropylene and hydrophilic and hydrophobic polymers.

It has excellent thermal stability and other advantages over traditional PVA, which makes it a versatile, durable and environmentally friendly material for supporting silk.


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These advantages include:


• water dissolves faster than pure PVA


• multiple materials can be used for printing


• enhanced adhesion


• biodegrades faster than PVA


Thermal stability at many high temperatures


The leading PVA filament brand can be printed at 215-225oc with a maximum substrate temperature of 60oC.

In addition, the AquaSys 120 filament can be printed at 240-245oc with a maximum base plate temperature of 130oC.


Adhesive properties


Being able to build materials that adhere to soluble supports, and vice versa, is critical to successful 3D printing.

Poor bonding between the support and adjacent layers of building materials can lead to peeling and printing failures.

The new material has been designed with enhanced adhesion, which can solve this problem.

It is compatible with various hydrophobic and hydrophilic materials used in filament driven 3D printing platforms and continues to be used with new construction materials.


To date, AquaSys 120 has successfully tested polyamide (nylon), copolyester (CPE), acrylonitrile butadiene styrene (ABS), thermoplastic polyurethane (TPU), polycarbonate (PC) and polyolefin (such as polypropylene (PP)).

It has significant advantages over traditional PVA fibers, which have limited adhesion to CPE, ABS, TPU, PC and PP.


solubility


In head-to-head dissolution tests of the same printed parts, the new filament material dissolved twice as fast as the leading brand PVA at room temperature (22 ° c) and six times faster at high temperatures (80 ° c).

Unlike PVA, which may form a gel before dissolving, especially at high temperatures, the new material can be dissolved cleanly at > 35oC without gelling.


Disposal and biodegradability


The new composites are based on naturally occurring carbohydrates that quickly mineralize in the environment.

The mineralization of this carbohydrate component may take hours or days.

The rest of the material biodegrades more slowly, but like PVA, they are eventually considered biodegradable using adaptive sludge from wastewater treatment facilities based on mineralization tests of respiratory treatment.