WO2016014024A1

WO2016014024A1 - High strength resin system formulated with nanodiamonds and method of making same

Info

Publication number: WO2016014024A1
Application number: PCT/US2014/047509
Authority: WO
Inventors: Andrey Factor; Marshall Weingarden; Wladimir BORODIN; Volodymyr IVASHCHENKO
Original assignee: Nano Mpi Holdings, Inc.
Priority date: 2014-07-22
Filing date: 2014-07-22
Publication date: 2016-01-28

Abstract

A cured polymer and nanodiamond mixture is formed that has nanodiamonds dispersed throughout the cured polymer. The nanodiamonds are substantially ungraphenated and are between 0.1% and 3% by weight to the resin. The nanodiamonds primary crystals are less than 10 nm in size.

Description

HIGH STRENGTH RESIN SYSTEM FORMULATED WITH

NANODIAMONDS AND METHOD OF MAKING SAME

TECHNICAL FIELD

The field of this invention relates to polymers, for example a high strength resin composition incorporating nanodiamonds and a method of making the same.

BACKGROUND OF THE DISCLOSURE

Polymers often referred to as resin systems have seen wide application. Often these resin systems are thermoset materials that are formed from a chemical reaction where the resin and hardener or infuser are mixed and undergo a permanent hardening or curing which cannot be reversed.

Many structural parts are made from different types of resin systems used in the composite industry for example polyester, vinyl ester, and epoxy.

For example, a two component endothermic system has a resin which forms a greater portion of the component and a catalyst sometimes referred to as a hardener or actuator. A two component system may also be exothermic when there is similarly a resin and catalyst plus an external energy source applied to the mixture. Single component systems have a resin and an energy source which may vary from heat, UV light, laser or infrared light to cure the resin.

It is known to blend fillers for example, clay particles, calcium carbonate, graphite or copper among others, are added to improve non-mechanical characteristics to increase volume and reduce cost. Fibers such as glass fibers or carbon fibers are added into the resin system to improve mechanical strength, facilitate the molding process and add specific characteristics that cannot be created with filler. The strength of the same cured resin varies from cure-to-cure creating a measurable and potentially significant standard deviation.

There is significant development in nanodiamond materials technology. One process for producing nanodiamonds is through detonation synthesis although other methods may become available. Extreme conditions of temperature and pressure are created in a hermetically sealed chamber from an intense explosion of carbon based raw materials. The raw material is converted into three types of materials; graphenated nanodiamond, forms of grapheme or other soot and a small amount of ungraphenated nanodiamonds. The nanodiamonds tend to agglomerate after production.

What is needed is a polymer system that is blended with and reinforced with a nanodiamond mixture that is substantially ungraphenated and that is dispersed throughout the cured polymer to make a more consistently strong polymer composite and a method for making the same.

SUMMARY OF THE DISCLOSURE

In accordance with one embodiment of the invention a cured polymer and nanodiamond mixture is formed that has nanodiamonds dispersed throughout the cured polymer. The nanodiamonds are substantially ungraphenated. The nanodiamonds are between 0.1% and 3% by weight to the polymer. The nanodiamonds primary crystals are lOnm in size or less. Preferably, the nanodiamonds are between 2-10 nm in size and are approximately 0.1% to 0.5% by weight to the resin.

In one embodiment, the polymer is a resin, for example, of marine or aviation or other grade epoxy and the nanodiamonds are detonation synthesis nanodiamonds or by any other method which allows the nanodiamonds to obtain a particle size of 2-10 nm with a nanodiamond dispersion in liquid media to reduce their agglomeration. In one embodiment, reinforcing fibers are also added to the polymer composite.

In accordance with another aspect of the invention, a method of making a cured polymer and nanodiamond composite includes the steps of producing nanodiamonds via a detonation synthesis technology; separating the nanodiamonds from soot; maintaining the nanodiamonds in a moist state to reduce agglomeration; introducing the nanodiamonds into the polymer before curing and curing the polymer and nanodiamond mixture. Preferably, a refinement technique after the detonation synthesis changes the ratio of substantially graphenated nanodiamonds to a blend that is substantially ungraphenated nanodiamonds. Preferably, the blend is over 99% of ungraphenated nanodiamsonds. In one embodiment the ungraphenated nanodiamonds are then created and/or separated from graphenated nanodiamonds and ungraphenated nanodiamonds are thoroughly mixed into one of the resin or catalyst to assure even distribution of the ungraphenated nanodiamonds. In one embodiment, reinforcing fibers are also mixed into a resin and catalyst mixture to create an even mixture for a complete reaction that creates the resin, nanodiamond and fiber composite.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

In accordance with one embodiment of the invention, a resin infused with substantially ungraphenated nanodiamonds is formed.

It is known that nanodiamonds are created through high pressure and temperatures resulting from a explosive occurrence in a hermetically sealed chamber. Although other methods may become available, the known explosive process is commonly referred to as detonation synthesis. The carbon of the explosive fuel creates a mixture that is 40-50% nanodiamonds and the rest being grapheme or other soot. The nanodiamonds are prevalently graphenated with small amounts of ungraphenated nanodiamonds being formed during the detonation synthesis. In general, nanodiamonds with a primary crystal of 10 nm or less are formed. Preferably, the nanodiamond primary crystal sizes are between 2-10 nm.

Ungraphenated nanodiamonds are not electrically conductive and are generally desirable to be introduced into resin composites to maintain the general non-conductivity of the resin composite. As such, refinement of the nanodiamonds is needed to remove the graphene shell from most of the graphenated diamonds to convert the blend of nanodiamonds to substantially ungraphenated diamonds. For example, the graphene shell may be chemically removed in an acid bath.

Through refinement, the nanodiamond blend is then separated from the soot. Preferably, the ungraphenated nanodiamonds are separated from both the graphenated nanodiamonds and soot. In either case, a refined nanodiamond blend of substantially ungraphenated nanodiamonds is obtained. The refined nanodiamond blend is maintained in the refinement output moist state, i.e. it contains some amount of liquid to reduce agglomeration and produce a stable additive product with minimal nanodiamond settling in the finished product and resulting in extended shelf life. For example, the liquid may be water, acid or urea. Reduction of agglomeration is important to maintain the size in the less than 10 nanometer range.

The refined blend of nanodiamonds in the moist state can then added to the resin system component. For example, polyester, vinyl ester, or epoxy resin can be used. Alternatively, the moist nanodiamond blend can be added to the catalyst, i.e., hardener. As the catalyst is mixed with the resin, there is a permanent change in the characteristics of the molecular bonding and surface tension of the cured resin. Prior to mixing or curing the resin system components, the nanodiamonds are thoroughly blended with the chosen resin system component to assure uniform disbursement. The resin with nanodiamonds or the hardener or catalyst with nanodiamonds is thoroughly blended to uniformly disperse the nanodiamonds throughout that component and then the combined resin, hardener/catalyst and nanodiamonds are thoroughly mixed to completely disperse the nanodiamonds throughout the resin composite. The resin is then allowed to cure.

The ungraphenated nanodiamonds create additional surfaces for molecular bonding between the resin composite components which increases the surface tension effect. The refinement process that produces ungraphenated nanodiamonds results in a material where the grapheme shell has been removed and the surface prepared for the carrying medium (i.e., resin or hardener).

Testing of a cured Adtech Probuild polymer epoxy without and with varying amounts of nanodiamonds at 0.5% and 1% by weight have been pull tested for peak force and stress. The results are in the following Table 1 :

Strength improvements are seen from the battery of tests to be up 46% using a concentration of 0.5% by weight of nanodiamonds. The lesser amount of nanodiamonds used gave better performance characteristics. Lower percentages are foreseen as low as 0.1% by weight depending on the size of the nanodiamonds and the percentage of ungraphenated nanodiamonds in the refined blend of nanodiamonds. It is seen that a preferred percentage will be approximately 0.3% by weight of ungraphenated nanodiamond. It should be noted that the standard deviation (SD) for the pull test dropped considerably for the two tested nanodiamond blends. In other words, a more consistent cured composite product is made by curing the resin with a nanodiamond enhanced component.

A second battery of tests was conducted to test both breaking strengths and rotational breaking points in Newtons (N) comparing several epoxy samples of epoxy without nanodiamonds are samples with 0.3% by weight of nanodiamonds that average results are as follows:

The 0.3% blend of nanodiamonds provides over a 40% improvement in breaking strength and over 12% increase in rotational strength.

In this fashion, less resin needs to be used because pull strength are both increased and are more consistent.

It is foreseen to add fibers and other filler to the resin composite before curing such as carbon or glass fibers depending on the desired characteristics and applications.

Variations and modifications are possible without departing from the scope and spirit of the present invention as defined by the appended claims.

Claims

CLAIMS The embodiments in which an exclusive property or privilege is claimed are defined as follows:

1. A cured polymer and nanodiamond mixture comprising:

nanodiamonds dispersed throughout a cured polymer;

said nanodiamonds being substantially ungraphenated:

said nanodiamonds being between 0.1% and 3% by weight to the polymer; and

said nanodiamonds being 10 nm in size or less.

2. A cured polymer and nanodiamond mixture as defined in claim 1 further comprising:

said nanodiamonds primary crystal being between 2-10 nm in size.

3. A cured polymer and nanodiamond mixture as defined in claim 2 further comprising:

said nanodiamonds being approximately 0.1% to 0.5% by weight to the resin.

4. A cured polymer and nanodiamond mixture as defined in claim 3 further comprising:

said resin being one of an epoxy, or polyester, and vinyl ester.

5. A cured polymer and nanodiamond mixture as defined in claim 1 further comprising: said nanodiamonds being detonation synthesis nanodiamonds of a particle size of 2-10 nm.

6. A cured polymer and nanodiamond mixture as defined in claim 1 further comprising:

said mixture including a reinforcing fiber.

7. A method of making a cured polymer and nanodiamond composite comprising:

producing nanodiamonds via a method which allows the nanodiamonds to obtain a particle size of 2-10 nm and to disperse in a liquid media to reduce their agglomeration;

refining said nanodiamonds produced from the detonation synthesis technology for changing the blend of nanodiamonds from substantially graphenated to a substantially ungraphenated blend of nanodiamonds;

separating said nanodiamonds from soot;

maintaining said nanodiamonds in a moist state to reduce possibility of agglomeration;

introducing said nanodiamonds into an uncured polymer;

mixing the polymer for dispersing the nanodiamonds throughout the resin composite; and

curing the polymer and nanodiamond mixture.

8. A method as defined in claim 7 further comprising:

said nanodiamonds being between 0.1% and .3% by weight relative to said cured resin.

9. A method as defined in claim 7 further comprising:

separating ungraphenated nanodiamonds from graphenated nanodiamonds and introducing said ungraphenated nanodiamonds into said uncured polymer.

10. A method as defined in claim 7 further comprising:

introducing said nanodiamonds into one of a resin or catalyst of said polymer; and

mixing the catalyst with said resin for dispersing said nanodiamonds throughout the uncured polymer.

1 1. A method as defined in claim 10 further comprising:

adding a reinforcing fiber to the mixing of the catalyst with the resin before curing the polymer and nanodiamond mixture.