WO2019142188A1

WO2019142188A1 - Polymeric products comprising fluorescent carbon based materials and methods of preparation thereof

Info

Publication number: WO2019142188A1
Application number: PCT/IL2019/050065
Authority: WO
Inventors: Michael SHTEIN; Amit HAVIV; Yonit Boguslavsky; Shai GERTNER
Original assignee: Dotz Nano Ltd
Priority date: 2018-01-18
Filing date: 2019-01-16
Publication date: 2019-07-25
Also published as: IL275928A

Abstract

The present invention relates to thermoset and thermoplastic polymeric products comprising fluorescent carbon based materials and methods for manufacturing them. The thermoset and thermoplastic polymeric products are ornamental or identification items characterized by having uniform or patterned fluorescence.

Description

POLYMERIC PRODUCTS COMPRISING FLUORESCENT CARBON BASED MATERIALS AND

METHODS OF PREPARATION THEREOF

Field of the Invention

The present invention relates to polymeric products comprising fluorescent carbon based materials and methods of manufacture thereof. Specifically, the invention relates to thermoset and thermoplastic polymeric products characterized by having either uniform or patterned fluorescence and to their manufacture by incorporation or impregnation of fluorescent carbon based materials.

Background of the Invention

Articles of manufacture, markings, labels, and packaging that include a fluorescent characteristic can and have been used to provide a means to verify the authenticity of the source of products. Such fluorescent characteristics may take the form of a fluorescent response when the articles, markings, labels, or packaging are irradiated with or exposed to electromagnetic radiation (EMR) having certain characteristics. In addition, fluorescent characteristics may be used in currency to verify its authenticity. Some traditional organic dyes or pigments (e.g., organic optical brightening agents) have been used to provide labels and packaging with fluorescent characteristics. However, these may suffer from a number of possible drawbacks. For example, traditional optical brighteners are sold in the open market making them accessible and therefore, easily copied. In some cases (i.e. fluorescent organic dyes or special pigments) the optical brighteners tend to be relatively expensive, rely on inclusion of toxic components (e.g., water-soluble aromatics), suffer from photobleaching upon repeated irradiation (especially high intensity EMR), resulting in loss of effectiveness over time, are suspected of being allergens, teratogens, and/or endocrine disrupters, and may be easily produced allowing for counterfeits. In addition, optical brighteners have been shown to leach into the wastewater and are difficult to biodegrade.

Fluorescent carbon based materials, which encompass, among others, fluorescent carbon dots (CDs) and photoluminescent carbon nanostructures (PCNs), have attracted considerable interest because of their diverse optical properties, depending on their molecular structure, crystal structure, size, size dependency, morphology, and chemical functionalization. For example, Graphene quantum dots (GQDs), which are individual single-atom-thick or a-few-atom-thick nanometer-sized planar sheet of graphitic carbon have been used, for example, as optical brighteners owing in part to their tunable photoluminescence (PL) properties, originated from quantum confinement. Fluorescent carbon dots (CDs) are carbon nanomaterials used in biosensing and bioimaging applications as they are characterized as biocompatibile, inexpensive and easily synthesized.

The use of fluorescent carbon based materials in molded articles of manufacture has potentially some significant advantages over the use of the more conventional phosphorous dyes, such as the ability to tune the emission wavelength, high quantum yield, low toxicity, high temperature resistance, relatively longer photostability and low scattering. Such articles may be used in authentication techniques or in bioimaging in medical devices for achieving better resolution of, for example, the progression of a device within a body cavity or many other applications without having the drawbacks of toxicity and high cost associated with currently used markers, such as metal-based quantum dots.

Other articles may have a more aesthetic value, such as ornamental or decorative products. It is therefore a purpose of the present invention to provide polymeric products comprising a polymer substrate and fluorescent carbon based materials dispersed therein.

It is a further object of the invention to provide methods for manufacturing such polymeric products.

Further purposes and advantages of this invention will appear as the description proceeds.

Summary of the Invention

The present invention provides a polymeric product comprising a polymer substrate and fluorescent carbon based materials dispersed therein. According to some embodiments, the fluorescent based materials are selected from: fluorescent carbon dots (CDs), photoluminescent carbon nanostructures (PCNs) or graphene quantum dots (GQDs). According to some embodiments, the polymeric product is characterized by having uniform fluorescence or patterned fluorescence. According to some embodiments, the product comprises fluorescent carbon based materials having different emission wavelengths.

According to some embodiments, the polymer substrate is thermoset polymer selected from: poly(epoxide), an acrylic, poly(dimethylsiloxane) thermoset, poly(urethanes), a copolymer thereof or their combination.

According to some embodiments, the polymer substrate is thermoplastic polymer selected from: Acrylonitrile butadiene styrene (ABS), poly(vinylchloride) (PVC), High density poly(ethylene) (HDPE), Low density poly(ethylene) (LDPE), Poly(propylene) (PP), poly(styrene) (PS), poly(methylmethacrylate) (PMMA), Natural rubber (NR), poly(oxymethylene) (POM), Polycarbonate (PC), Poly(ethylene terephthalate) (PET), poly(etheretherketone) (PEEK), poly(caprolactam) (Nylon 6, PA6), a copolymer thereof, terpolymer thereof, or their combination.

According to some embodiments, the polymeric product is an identification item, and in other embodiments, the polymeric product is an ornamental item.

Another aspect of the invention relates to a method for manufacturing the polymeric product comprising the steps of: adsorbing fluorescent carbon based materials onto a carrier to form a carrier-fluorescent complex; mixing the carrier-fluorescent complex with a thermoset polymer resin, forming a master batch; optionally, diluting the master batch with thermoset polymer resin; and admixing the master batch with the thermoset hardener, thereby initiating curing. According to some embodiments, the master batch is diluted with said thermoset polymer to a concentration of between 0.1-5 %wt. According to some embodiments, the curing comprises crosslinking, photocuring, or a curing combination comprising the foregoing. According to some embodiments, the method comprises a step of molding the process batch prior to curing.

According to some embodiments, mixing the carrier-fluorescent complex with the thermoset polymer resin is performed at a maximum loading level of between 20-30 %wt of carrier to resin, depending on the carrier and the resin.

Another aspect of the invention relates to a method for manufacturing the polymeric product comprising the steps of: adsorbing fluorescent carbon based materials onto a carrier to form a carrier-fluorescent complex; mixing the carrier-fluorescent complex with a composition comprising a thermoplastic polymer, under extrusion conditions, forming a master batch; and diluting the master batch with a thermoplastic resin, thereby forming a process batch ready for injection molding. According to some embodiments, the extrusion conditions are at between 200-300 C° and at maximum loading level of 5-10 %wt of carrier to resin. According to some embodiments, the master batch is diluted with a thermoplastic resin to a concentration of between 0.005-1 %wt.

According to some embodiments, adsorbing fluorescent carbon based materials onto a carrier comprises the steps of: solubilizing the fluorescent carbon based materials in a solvent; adding the carrier to the fluorescent carbon based materials solution under continuous mixing; separating the -fluorescent complex from the solvent; drying the carrier-fluorescent complex; and grinding the carrier-fluorescent complex into a fine powder.

According to some other embodiments, adsorbing fluorescent carbon based materials onto a carrier comprises the steps of: solubilizing the carrier in a solvent, optionally, under heating conditions; adding the fluorescent carbon based materials to the carrier solution and mixing; drying the carrier-fluorescent complex; and grinding the carrier- fluorescent complex into a fine powder. According to some other embodiments, the solubilizing the carrier in a solvent is performed under heating conditions of between 60-80 C°.

According to some embodiments, drying the carrier-fluorescent complex is done in a vacuum oven at a temperature of between 60-120 C° and between 20-50 mBar.

According to some embodiments, the carrier in the above methods is selected from starch, Al₂0₃, Ti0₂, ZnO, Ce0₂, Si0₂, or a combination thereof. According to some embodiments, the ratio between the fluorescent carbon based materials and the carrier is between 1:850 and 1:50, or between 100 ppm and 20,000 ppm.

According to some embodiments, the solvent is selected from: ethanol (EtOH), isopropyl alcohol (IPA), water, or a solvent composition comprising one or more of the foregoing. According to some embodiments, the step of mixing the carrier-fluorescent complex is preceded by filtering the carrier-fluorescent complex.

According to some embodiments, the step of mixing the master batch with the thermoplastic resin is followed by a step of forming the process batch into pellets, rods, powder or a physical form comprising one or more of the foregoing.

Another aspect of the invention relates to a method for manufacturing the polymeric product by impregnating a thermoplastic polymer with fluorescent carbon based materials comprising the steps of: forming a powder comprising composite thermoplastic polymer and the fluorescent carbon based materials; using a first solvent which is thermodynamically compatible with both the thermoplastic polymer and the fluorescent carbon based materials, solubilizing the powder; and removing the first solvent forming a composite powder of thermoplastic polymer and fluorescent carbon based materials. According to some embodiments, the method further comprises washing the powder with a second solvent which may optionally be thermodynamically compatible with the fluorescent carbon based materials only. According to some embodiments, the second solvent is the same as the first solvent. According to some embodiments, the second solvent is acetone.

According to some embodiments, the step of forming the composite powder of thermoplastic polymer and fluorescent carbon based materials comprises the following steps: admixing the thermoplastic polymer into a reactor containing the first solvent, forming a polymer solution; while stirring, admixing the fluorescent carbon based materials into the polymer solution forming composite thermoplastic polymer- fluorescent solution; transferring the composite thermoplastic polymer-fluorescent solution to a dryer; removing the first solvent, forming a coarse cake; and milling the coarse cake, forming a fine powder of composite thermoplastic polymer and fluorescent carbon based materials. According to some embodiments, the mill is a hammer mill or a ball mill.

According to some embodiments, the first solvent is selected from: acetone, acetonitrile, tetrahydrofuran (THF), dimethylformamide (DMF), dichloromethane (DCM), or a solvent composition comprising the foregoing.

According to some embodiments, the above method further comprises flushing the reactor and/or the dryer. In some of these embodiments, flushing is done with an inert gas selected from: Helium, Argon, Nitrogen, or an inert gas composition comprising one or more of the foregoing

According to some embodiments, the step of admixing the fluorescent carbon based materials is preceded by a step of heating the reactor. The reactor may be heated to a temperature of between 50 °C to 100 °C depending on the solvent boiling point.

According to some embodiments, the step of transferring the composite thermoplastic polymer-fluorescent solution to the dryer, is preceded by a step of cooling the reactor to a temperature of between 20 °C and 27 °C.

According to some embodiments, the dryer is a paddle dryer and the step of removing the solvent occurs simultaneously with building a vacuum in the paddle dryer.

A further aspect of the invention relates to a method for manufacturing a polymeric product by impregnating a thermoset polymer with fluorescent carbon based materials, comprising the steps of: forming a thermoset resin to be impregnated with fluorescent carbon based materials; increasing the free volume of a thermoset resin to a point where the average free volume of the thermoset resin is equal to or larger than the average volume of each of the fluorescent carbon based materials; admixing a solution of fluorescent carbon based materials; and decreasing the free volume of the thermoset resin to the point where the average free volume of the thermoset resin is smaller than the average volume of each of the fluorescent carbon based materials. According to some embodiments the polymeric product is a rod, a pellet, or a powder.

According to some embodiments of the above method, the thermoset polymer is selected from: a poly(epoxide), an acrylic, poly(dimethylsiloxane) thermoset, poly(urethanes), a copolymer, terpolymer or a combination thereof.

According to some embodiments, the step of increasing the free volume comprises heating the thermoset resin, exposing the thermoset resin to a thermodynamically compatible plasticizer, decreasing atmospheric pressure, or a combination of the foregoing. According to some embodiments, the plasticizer is selected from: cycloaliphatic amine, aliphatic amine, toluene, glycol ether-ester, dibutylphthalate (DBP), benzyl benzoate (BnBzO), polyisobutylene (PIB), or a combination thereof.

According to some embodiments of the above method, the step of decreasing the free volume comprises cooling the thermoset resin, removing the thermodynamically compatible plasticizer, increasing atmospheric pressure, or a combination of the foregoing. According to some of these embodiments, the fluorescent carbon based materials are modified to be soluble in the plasticizer.

According to some embodiments of the above method, the step of decreasing the free volume of the resin is followed by washing the thermoset resin with a solvent specific for the fluorescent carbon based materials.

According to some embodiments of the above methods, the fluorescent carbon based materials are modified to be thermodynamically compatible with the thermoplastic or thermoset polymer. According to some embodiments, the polymeric product manufactured according to the above methods, is an identification item. According to some other embodiments, the polymeric product manufactured according to the above methods, is an ornamental item.

Brief Description of the Drawings

Fig. 1 shows Graphene quantum dot (GQD) adsorbed on silica particles under ambient light and UV irradiation;

Fig. 2 is a graph illustrating the spectra of silica samples activated by different amounts of quantum dots;

Fig. 3 shows the photoluminescence (PL) of GQDs at 1250 ppm w/w ratio to silica particles under UV irradiation;

Fig. 4 shows the effect of swelling time of polyamide on the PL intensity of GQDs;

Fig. 5 shows the effect of various solvents/plasticizers on the ability to incorporate GQDs into swollen polyamide under ambient light and under ultraviolet (UV) electromagnetic radiation (EMR);

Fig. 6 shows the effect of various solvents on the ability to incorporate GQDs into solubilized methacrylate under ambient light and under UV EMR;

Fig. 7A shows GQDs embedded in thermoplastic poly(urethane) (TPU) matrix by comingled dissolution under ambient light (left) and 365 nm UV light (right), with the GQD emission spectra following UV excitation at 350 nm shown in Fig. 7B; Fig. 8 shows the incorporation of GQDs with various emission colors in TPU by comingled dissolution under ambient light (Fig. 10A) and under UV EMR (Fig. 10B);

Fig. 9 shows GQDs embedded in elastomer cured silicone matrix under ambient light and under UV EMR;

Fig. 10 shows two types of GQDs embedded in silicone matrix by swelling/deswelling under ambient light and under UV EMR;

Fig. 11 shows heterogeneous mold which is impregnated with several types of fluorescent carbon dots having different emission wavelengths into epoxy under ambient light and 365 nm UV light;

Fig. 12 schematically shows one embodiment for adsorbing GQDs onto carriers;

Fig. 13 schematically shows one embodiment for solvent impregnation of GQDs in thermoplastic polymers; and

Fig. 14 schematically shows one embodiment for polymer dissolution in the presence of GQDs used to embed the GQDs.

Detailed Description of Embodiments of the Invention

In a first aspect, the invention is directed to a polymeric product comprising a polymer substrate and fluorescent based materials dispersed therein.

As used herein, the term "polymeric product" relates to an article of manufacture made of synthetic polymers and consisting mainly of carbon atoms. The synthetic polymer may be a thermoset polymer or a thermoplastic polymer. According to some embodiments, the polymer substrate is a thermoset polymer. In some of these embodiments, the thermoset polymer is selected from: poly(epoxide) (epoxy), an acrylic, poly(dimethylsiloxane) thermoset, poly(urethanes), Melamine formaldehyde, Polyester resins, Phenol formaldehyde (PF, Bakelite), a copolymer thereof, a terpolymer thereof, or their combination.

According to some embodiments, the polymer substrate is a thermoplastic polymer. In some of these embodiments, the thermoplastic polymer is selected from: Acrylonitrile butadiene styrene (ABS), poly(vinylchloride) (PVC), High density poly(ethylene) (HDPE), Low density poly(ethylene) (LDPE), Poly(propylene) (PP), poly(styrene) (PS), poly(methyl methacrylate) (PMMA), Natural rubber (NR), poly(oxymethylene) (POM), Polycarbonate (PC), Polyethylene terephthalate) (PET, cPET, aPET and/or PETg), poly(etheretherketone) (PEEK), poly(caprolactam) (Nylon 6, PA6), a copolymer thereof, terpolymer thereof, or their combination.

As used herein, the term "fluorescent carbon based materials" relates to carbon materials having fluorescence (or interchangeably, photoluminescence (PL)) properties, the term encompasses carbon molecules, carbon based oligomers and polymer/co-polymer structures, carbon dots (CDs), photoluminescent carbon nanostructures (PCNs) such as graphene quantum dots (GQDs), graphene oxide quantum dots, carbon nanotube quantum dots or a combination of one or more of the foregoing. Specifically, the fluorescent carbon based materials may originate from any organic carbon source which is non-toxic. The carbon nanotube quantum dots can be single wall nanotube (SWNT), or multi-wall nanotube (MWNT), or a combination thereof.

In some embodiments, the fluorescent carbon based materials can be nano-sized (of less than 10 nm in size) structures of carbon molecules (more than a single atom) having dimensionality that is anywhere from quasi-one dimension (e.g., quantum dot, nanoribbon, nanobelt), to three dimensional (e.g., multilayer graphene structures). Encompassed in these nano-sized structures, are graphene, graphdiyne, fullerene, nanocage, multilayer graphene dot, nanodiamond, nanotube, nanowire, nanohorn, or a carbon dots composition comprising one or more of the foregoing.

In some embodiments, the polymeric products are characterized as having uniform fluorescence. While in other embodiments, the polymeric products have a patterned fluorescence. The polymeric products may also comprise fluorescent carbon based materials having different emission wavelengths producing different colors under electromagnetic radiation (EMR). Polymeric products having unique patterning can be used in authentication and tagging of products. Thus, in some embodiments, the polymeric product is an identification item.

Other applications of the polymeric product of the invention may have a more aesthetic or decorative value. Thus in some embodiments, the polymeric product is an ornamental item.

Provided herein are methods for manufacturing polymeric products comprising fluorescent carbon based materials. The polymer substrate may be a thermoset or thermoplastic polymer.

In some embodiments of the method for manufacturing a polymeric product, where the polymer is a thermoset polymer, the method comprises: adsorbing fluorescent carbon based materials onto a carrier to form a carrier-fluorescent complex; mixing the carrier-fluorescent complex with a thermoset polymer resin (Part A), forming a master batch; optionally, diluting the master batch with the thermoset polymer resin; and adding a thermoset hardener (Part B) comprising a crosslinker and catalyst, thereby initiating curing. By mixing Part A with Part B the curing process is initiated, until the thermoset matrix is fully cured. In some embodiments, curing time may be reduced by elevating temperature. According to some embodiments, mixing the carrier-fluorescent complex with the thermoset polymer resin is performed at a maximum loading level of between 20-30 %wt of carrier to resin, depending on the carrier and the resin. In some embodiments, the master batch can be diluted with the resin (Part A) to the desired and optimal concentration, for example, of between 0.1-5 %wt.

In some embodiments of the method for manufacturing a polymeric product, where the polymer is a thermoplastic polymer, the method comprises: adsorbing fluorescent carbon based materials onto a carrier to form a carrier-fluorescent complex; mixing the carrier-fluorescent complex with a composition comprising a thermoplastic polymer under extrusion conditions, forming a master batch; diluting the master batch with a thermoplastic resin, thereby forming a process batch ready for injection molding.

According to some embodiments, mixing the carrier-fluorescent complex with the thermoset polymer resin is performed under extrusion conditions at between 200-300 C°, depending on the specific resin, and at maximum loading level of 5-10 %wt of carrier to resin, depending on the carrier and the resin.

In some embodiments, the master batch can be diluted with a thermoplastic resin to a concentration of between 0.005-1 %wt.

In some embodiments, the method for manufacturing a thermoset polymer further comprises a step of molding the process batch prior to curing. As used herein, the term "molding" relates to the casting of the polymeric process batch into molds (whether it be silicone, plastic or metal) followed by curing.

In some embodiments, curing the process batch comprises crosslinking, photocuring, or a curing combination comprising the foregoing. As used herein, the term "curing" refers to chemical crosslinking within the resin and between different layers of resin. Other chemical changes may occur at the same time of crosslinking.

As used herein, the term "crosslinking" refers to the formation of covalent bonds between thermoset resin monomers, oligomers or polymers and polymers formed therefrom. Such chemical changes are distinguished from a physical change such as melting. In thermoset polymers, unlike thermoplastic polymers, the curing is considered irreversible. As used herein, the term "partial cure", "partial curing" or "partially cured" refers to the amount of chemical crosslinking within the resin and between different layers of resin to form covalent bonds between the resin molecules and layers. The term "fully curing" or "fully cured" refers to an amount of chemical crosslinking within the resin and between different layers of resin to form covalent bonds between the resin molecules and layers such that subjecting the resin to additional curing conditions does not provide appreciably more of the same type of covalent bonding. Accordingly, the term "fully" does not imply that all of the crosslinking moieties must be covalently bonded.

As used herein, the term "master batch" relates to a mixture of ingredients which can be added to a polymer in order to impart a particular property to that polymer. The use of a master batch, rather than adding the fluorescent carbon based materials directly to the final polymer composition, can make subsequent processing easier as well as improving the homogeneity of the fluorescent carbon based materials in the final polymer.

Incorporation of fluorescent carbon based materials into a thermoset resin is shown in Fig. 12. As illustrated, fluorescent carbon based materials 100 (either bare and/or adsorbed onto a carrier) are mixed 401, 402 with a thermoset prepolymer resin 110 to form a master batch 120, at maximum loading level. Master batch 120 may then be diluted 403 with the resin (Part A) to the desired/optimal concentration 130. A thermoset hardener (Part B) (comprising a crosslinker and catalyst) is added and mixed 404 with Part A 130, for initiating curing.

In some embodiments, as illustrated in Fig. 12, an extruder 140 (or 3D printing, thermoforming, blow molding, etc.) may be applied for further processing. The resin thus can be formed separately into powders, rods, pellets 150 for later use, by additional diluting polymer and after mixing, can likewise be extruded, or thermoformed or blow molded and used in other applications.

According to some embodiments, the step of mixing the carrier-fluorescent complex is preceded by filtering the carrier-fluorescent complex.

In some embodiments, the thermoset resins, that can be used for incorporating (or doping, embedding, impregnating) the fluorescent carbon based materials, are phenolic resins; lignin resins; tannin resins; amino resins; polyimide resins; isocyanate resins; (meth)acrylate resins; vinylic resins; styrenic resins; polyester resins; melamine resins; vinyl ester resins; maleimide resins; epoxy resins; polyamidoatnine resins; or copolymers, terpolymers, and mixtures thereof.

In some embodiments, the method for manufacturing a thermoplastic polymer further comprises a step of forming the process batch into pellets, rods, powder or a physical form comprising one or more of the foregoing.

The step of adsorbing fluorescent carbon based materials onto a carrier to form a carrier-fluorescent complex comprises: solubilizing the fluorescent carbon based materials in a solvent; adding the carrier to the fluorescent carbon based materials solution and allowing the fluorescent carbon based materials to attach to the carrier surface under continuous mixing; separating the carrier-fluorescent complex from the solvent; drying the carrier-fluorescent complex; and grinding the carrier-fluorescent complex into a fine powder. Alternatively, according to some embodiments, the carrier (and not the fluorescent carbon based materials) is solubilized in a solvent, in which case, the step of adsorbing fluorescent carbon based materials onto a carrier comprises: solubilizing the carrier in a solvent, optionally, under heat; adding the fluorescent carbon based materials to the carrier solution and mixing to a homogenous solution; drying the carrier-fluorescent complex; and grinding the carrier-fluorescent complex is into a fine powder.

In some embodiments, solubilizing the carrier in a solvent is performed under heating conditions of between 60-80 C°, for accelerating the dissolution reaction.

According to some embodiments of the above methods, the step of drying the carrier- fluorescent complex is done in a vacuum oven at a temperature of between 60-120 C° and between 20-50 mBar, until brittle coprecipitation of the carrier resin is achieved.

In some embodiments, the solvent for adsorbing fluorescent carbon based materials, used in the methods described herein, is ethanol (EtOH), isopropyl alcohol (IPA), water, Tetrahydrofuran (THF), Dichleromethane (DCM) or a solvent composition comprising one or more of the foregoing.

In some embodiments, the carrier for adsorbing fluorescent carbon based materials used in the methods described herein, may be selected from starch, Al₂0₃, Ti0₂, ZnO, Ce0₂, Si0₂, or a composition comprising a combination thereof.

According to some embodiments, the carrier is modified Si0₂, which may be Si0₂(NH)₂. In these embodiments the solvent used for adsorbing fluorescent carbon based materials onto a carrier is a solvent composition comprising ethanol (EtOH), ethylene dichloride (EDC), and triethylamine (TEA). In some embodiments, the ratio between the fluorescent carbon based materials and the carrier can be betweenl:850 and 1:50, or between 100 ppm and 20,000 ppm.

In an embodiment, the concentration of fluorescent carbon based materials in the master batch can be between 0.005% (W fluorescent carbon based materials/W master batch) and 1% fluorescent carbon based materials (W/W), and can be adjusted based on the requirements of the polymeric product. For example, the concentration of fluorescent carbon based materials in the final product can be between 0.005% (W/W) and 1% (W/W) fluorescent carbon based materials.

In some embodiments, the dry milling/grinding used in the methods described herein can be performed on, for example, attritor mills, nutating mills, tower mills, pearl mills, planetary mills, vibratory mills, eccentric vibratory mills, gravity-dependent-type ball mills, rod mills, roller mills, crusher mills or a mill combination (in other words, a combination of mills leading in progression to the desired colloidal size), comprising one or more of the foregoing dry mills.

A further aspect of the invention relates to the incorporation (or doping, embedding, impregnating) of fluorescent carbon based materials into the substrate polymers directly, even without the use of carriers, by achieving relative parity in sizes between the polymer substrate and the fluorescent carbon based materials. The fluorescent carbon based materials are entrapped within the polymeric physical matrix itself, either with or without a carrier. This can be achieved, for example, by swelling the polymer substrate, whether thermoset (see Figs. 9A-10B) or thermoplastic (Figs. 4-7B).

Accordingly, in some embodiments, the invention provides methods for manufacturing polymeric products comprising fluorescent carbon based materials by impregnating thermoplastic or thermoset polymers with fluorescent carbon based materials. As used herein the term "impregnated" or "impregnation" refers to the act of incorporating (e.g., modified) fluorescent carbon based materials into a polymeric product wherein the resultant polymeric product is said to have fluorescent characteristics upon being irradiated with electromagnetic radiation (EMR). Any impregnation step disclosed herein may result in (i) uniform fluorescent appearance achieved by incorporation of the fluorescent carbon based materials and/or the carrier-fluorescent complex completely and wholly throughout the polymeric product or (ii) a patterned fluorescence achieved from scattering of the fluorescent carbon based materials and/or the carrier-fluorescent complex throughout the polymeric product.

In some embodiments, the method for manufacturing a polymeric product comprising fluorescent carbon based materials by impregnating thermoplastic polymers, comprises: forming a powder comprising composite thermoplastic polymer and the fluorescent carbon based materials; using a first solvent which is thermodynamically compatible with both the thermoplastic polymer and the fluorescent carbon based materials, solubilizing the powder; and removing the first solvent, thereby obtaining a composite powder of thermoplastic polymer and fluorescent carbon based materials.

According to some embodiments, the method further comprises, washing the powder with a second solvent.

One embodiment of the method of for manufacturing a polymeric product comprising fluorescent carbon based materials by impregnating thermoplastic polymers is schematically shown in Fig. IB. As illustrated, fluorescent carbon based materials 210 and a first solvent 211, are added 501, 502 and admixed 503 in a reactor 220, into which the thermoplastic polymer resin powder 221 (or thermoset "prepolymer" meaning a compound, monomer or oligomer used to prepare a polymer, and includes, without limitation, both homopolymer and copolymer oligomers) is added 504. The sample is allowed 505 to react 230 while being washed 506 with a second solvent and filtered 240 as long as 507, fluorescence is detected in the filtrate 250. Once it is determined 250 that there is no fluorescence in the filtrate, indicating that all free fluorescent carbon based materials are either removed or incorporated, the residue is transferred 509 to a dryer 260, or another vessel where the solvent(s) can be removed.

According to some embodiments, the step of forming the composite powder of thermoplastic polymer and fluorescent carbon based materials comprises: admixing the thermoplastic polymer into a reactor containing the first solvent, forming a polymer solution; while stirring, admixing the fluorescent carbon based materials into the polymer solution forming composite thermoplastic polymer-fluorescent materials solution; transferring the composite thermoplastic polymer-fluorescent materials solution to a dryer (i.e. rotary evaporator or vacuum oven); removing the first solvent, forming a coarse cake; and milling the coarse cake, forming a fine powder of composite thermoplastic polymer and fluorescent carbon based materials.

In some embodiments of the method, the first solvent is selected from: acetone, acetonitrile, tetrahydrofuran (THF), dimethylformamide (DMF), dichloromethane (DCM), or a solvent composition comprising the foregoing. The first and second solvent can be the same or different. For example, while the first solvent is configured to be thermodynamically compatible with both the fluorescent carbon based materials and polymer substrate, the second solvent can be thermodynamically incompatible with the polymer substrate, while having higher compatibility with the fluorescent carbon based materials (whether modified or not), thereby removing the non-impregnated fluorescent carbon based materials from the mixture. Thus, in some embodiments, the second solvent is the same as the first solvent. Alternatively, the second solvent may be thermodynamically compatible with the fluorescent carbon based materials only. In some embodiments, the second solvent is acetone.

According to some embodiments, the method further comprises flushing the reactor and/or the dryer. As used herein, the term "flushing" refers to the introduction of an inert (non-combustible) gas into a closed system (for example, herein, a reactor or dryer). In some embodiments, the inert gas used for flushing is Helium, Argon, Nitrogen, or an inert gas composition comprising one or more of the foregoing.

According to some embodiments, the step of admixing the fluorescent carbon based materials is preceded by a step of heating the reactor. For example, the reactor may be heated to a reflux temperature of between 40 °C to 100 °C, depending on the solvent boiling point.

According to some embodiments, the step of transferring the composite thermoplastic polymer-fluorescent based materials solution to the dryer is preceded by a step of cooling the reactor to a temperature of between 20 °C and 27 °C.

One embodiment of the method of forming the composite resin-fluorescent carbon powder is provided in Fig. 14. As shown, a first solvent B10 (e.g., acetone, acetonitrile, tetrahydrofuran (THF), dimethylformamide (DMF), dichloromethane (DCM), or a solvent composition comprising the foregoing) is added 601 to reactor 300. The thermoplastic polymer 320 is admixed 602 to the reactor 300 forming a polymer solution under stirring, the fluorescent carbon based materials 330 are admixed 603 into the polymer solution 300 forming a composite thermoplastic polymer-fluorescent carbon materials solution. The composite thermoplastic polymer solution is transferred 605 to dryer 350 for removing the first solvent, forming a coarse cake; the coarse cake is then milled 360 (using, for example, a ball mill, a hammer mill or similar crushers), forming a fine powder of composite thermoplastic polymer and fluorescent carbon based materials. As shown in Fig. 14, the method may further comprise flushing the reactor BOO via 604 and/or flushing the dryer 350 via 604', using, for example nitrogen, argon or helium gas. Reactor 300 can be preheated prior to inserting the components for example, to a reflux temperature. Likewise, prior to transfer 605 of the solution from reactor 300 to dryer 350, reactor 350 can be cooled to, for example, a temperature of 20 °C or 27 °C (room temperature (RT)). Dryer 350 can be, in some embodiments, a paddle dryer. Furthermore, the step of removing the solvent can be configured to take place simultaneously with building a vacuum in the paddle dryer, for example between 40 and 50 mBar.

In some embodiments, the method for manufacturing a polymeric product comprising fluorescent carbon based materials by impregnating thermoset polymers, comprises: forming a thermoset resin to be impregnated with fluorescent carbon based materials; increasing the free volume (in other words, the volume not occupied by the molecules and their bonds) of a thermoset resin to a point where the average free volume of the thermoset resin is equal to or larger than the average volume of each of the fluorescent carbon based materials; admixing a solution of fluorescent carbon based materials; and decreasing the free volume of the thermoset resin to the point where the average free volume of the thermoset resin is smaller than the average volume of each of the fluorescent carbon based materials. In an embodiment, increasing the free volume results in swelling of the thermoset resin.

According to some embodiments, the thermoset polymer used for impregnating fluorescent carbon based materials is selected from: a poly(epoxide), an acrylic, poly(dimethylsiloxane) thermoset, poly(urethanes), a copolymer, terpolymer or a combination thereof. In some embodiments, the thermoset product is a rod, a pellet, or a powder. Increasing the free volume of the thermoset resin, can be done, for example, by heating the thermoset resin, exposing the resin to a thermodynamically compatible plasticizer, decreasing atmospheric pressure, or a combination of the foregoing. Therefore, the step of increasing the free volume, in some embodiments, comprises heating the thermoset resin, exposing the thermoset resin to a thermodynamically compatible plasticizer, decreasing atmospheric pressure, or a combination of the foregoing. Suitable plasticizers may be selected from: cycloaliphatic amine, aliphatic amine, toluene, glycol ether-ester, dibutylphthalate (DBP), benzyl benzoate (BnBzO), polyisobutylene (PIB), or a combination thereof.

As used herein, the term "plasticizer" is used in the conventional sense of the term to refer to a relatively low molecular weight compound that is miscible with a polymer or polymer blend and decreases the glass transition temperature and elastic modulus thereof. Additionally, or alternatively, the term "plasticizer" refers to the conventional meaning of this term as an agent which softens a polymer, thus providing flexibility, durability, etc. Plasticizers may be advantageously used in amounts of, for example, from 0.01 to 45% by weight, e.g., from 3 to 15% by weight of the polymer, although other concentrations may be used to provide desired flexibility, durability, etc. Plasticizers which may be used in certain embodiments, include one or more of: aliphatic carboxylic acids; aliphatic carboxylic acid metal salts; aliphatic esters; aliphatic amides; alkyl phosphate esters; dialkylether diesters; dialkylether esters; tricarboxylic esters; epoxidized oils and esters; polyesters; polyglycol diesters; alkyl alkylether diesters; aliphatic diesters; alkylether monoesters; citrate ester, dicarboxylic esters; vegetable oils and their derivatives; esters of glycerine; ethers, etc. For example, with the polymers described herein, the plasticizers may include one or more aliphatic acids (e.g., oleic acid, linoleic acid, stearic acid, palmitic acid, adipic acid, lauric acid, myristic acid, linolenic acid, succinic acid, malic acid, cerotic acid, etc.), one or more low molecular weight aliphatic polyesters, one or more aliphatic amides (e.g., oleamide, stearamide, linoleamide, cycle-n-lactam, e-caprolactam, lauryl lactam, N,N-dibutyl stearamide, N,N-dimethyl oleamide, etc.), one or more aliphatic carboxylic acid esters (e.g., methoxyethyl oleate, diisooctyl sebacate, bis(2-butoxyethyl) adipate, dibenzyl sebacate, isooctyl- isodecyl adipate, butyl epoxy fatty acid ester, epoxidized butyl acetoricinoleate, and low molecule weight (300-1200) poly(l, 2-propylene glycol adipate, etc.), one or more aliphatic carboxylic acid metal salts (e.g., magnesium oleate, ferrous oleate, magnesium stearate, ferrous stearate, calcium stearate, zinc stearate, magnesium stearate, zinc stearate pyrrolidone, etc.). In particular, the plasticizer can be cycloaliphatic amine, aliphatic amine, toluene, glycol ether-ester, dibutylphthalate (DBP), benzyl benzoate (BnBzO), polyisobutylene (PIB), or a plasticizer combination comprising the foregoing. It is contemplated that increased free volume, and thus higher fluorescent carbon particle loading can be achieved by using branched polymers, for example, highly branched (meaning that the polymeric chains are connected to one another to a high degree thereby forming a three-dimensional framework) poly(ethylene) can also be used and plasticizers can be short molecular number oligomers of the polymer used to entrap the fluorescent carbon based materials.

Once the fluorescent carbon based materials have been impregnated into the thermoset polymer, there is need to remove the plasticizer. Thus, in some embodiments, the step of decreasing the free volume comprises cooling the thermoset resin, removing the thermodynamically compatible plasticizer, increasing atmospheric pressure, or a combination of the foregoing. In some of these embodiments, the fluorescent carbon based materials can be modified to be soluble in the plasticizer. In some further embodiments, the step of decreasing the free volume of the resin is followed by washing the thermoset resin with a solvent specific for the fluorescent carbon based materials.

When incorporating (or doping, embedding, impregnating) the thermoset resins, thermoplastic resins or resin complexes (in other words, a mixture of one or more thermoplastic resins and one or more thermoset resins, where at least some of the thermoplastic resin(s) and at least some of the thermoset resin(s) are chemically bonded to one another), with the fluorescent carbon based materials using the methods described herein, it may be necessary to further cure the resins to achieve the final physico-chemical characteristics of the final product.

In some embodiments, and to prevent substantial phase separation during and/or after processing, the carrier and/or the fluorescent carbon based materials are modified to make them thermodynamically and/or mechanically compatible with the polymer substrate. As used herein, the term "thermodynamic compatibility" refers to the miscibility of the fluorescent carbon based materials and/or the carrier in the resin, presenting a single phase transition temperature (glass transition (Tg) and/or rotational transition (Tb)). Also, as used herein "mechanical compatibility" refers to compatibility sufficient to avoid gross phase separation under processing conditions, such as extension, extrusion, 3D printing, blow molding, thermoforming and the like. In addition, the thermodynamic and mechanical compatibility is sufficient to avoid leaching out of the resin (in other words, the thermoset and/or thermoplastic polymer, copolymer, terpolymer or a polymer combination comprising the foregoing), under normal use of the product formed, whether static resin or an elastomer.

Accordingly, in order to facilitate improved incorporation or impregnation using the methods of manufacture of the invention, the fluorescent carbon based materials can be modified to make them more compatible with the polymer substrate. These modifications can affect thermodynamic compatibility and/or mechanical compatibility of the fluorescent carbon based materials. Thus, in some embodiments of the invention, the fluorescent carbon based materials are modified to be thermodynamically compatible with the thermoplastic or thermoset polymer. Examples of such modifications include, but are not limited to, substituting alkoxysilane on the fluorescent carbon based materials surface for incorporation into silicone (PDMS), or poly(sulfone) polymers, or attaching bisphenol-A for incorporation into poly(urethane), poly(carbonate) or other poly(ether) resins. Similarly, propylene groups for Poly(propylene) (PP). In certain other embodiments the fluorescent carbon based materials are modified by substituting alkoxysilane groups configured to polymerize with tetraethylorthosilicate (TEOS) to form a hard shell on the silica beads.

In addition, selection of the type of fluorescent carbon based materials used could depend on the surface properties of the resin impregnated. It is contemplated that where surface modification of the fluorescent carbon based materials is necessary, the modification would be one which will favorably affect the fluorescence (or photoluminescence (PL)) of the impregnated resin. For example, since carbon nanotubes (single- and/or multi- walled) have excitonic PL, surface modification may affect quantum yield and the like. Accordingly, there is need for thermodynamic compatibility between the surface-modified fluorescent carbon based materials and the polymeric resin in which it is incorporated (or integrated or solubilized or embedded or entrapped, interchangeably).

In some embodiments, the methods of manufacture are configured to impart uniform fluorescent properties to the polymeric products. In some other embodiments, the methods enable obtaining polymeric products having a patterned fluorescence. In some of these embodiments, the polymeric products comprise fluorescent carbon based materials having different emission wavelengths producing different colors under electromagnetic radiation (EMR). Polymeric products having unique patterning can be used in authentication and tagging of products. Thus in some embodiments, the methods of manufacture allow obtaining a polymeric product which is an identification item.

Other applications of the polymeric product of the invention may have a more aesthetic or decorative value. Thus in some embodiments, the methods of manufacture facilitate the preparation of a polymeric product which is an ornamental item.

The invention will be further described and illustrated in the following examples. Examples

Example 1

Adsorbing GQDs onto Silica particles

A solution of GQDs was added to a predetermined solvent. The solvent solution was added to silica (Si0₂) powder in 20ml vials. The adsorption was performed under constant magnetic stirring (550 rpm) at room temperature (RT) for 2h, followed by removing the solvent in oven (80 °C). A white color powder was obtained. When water was used as the solvent, removal of the solvent was carried out by freeze dry technique. Table I shows the effect of the predetermined solvent on the non-specific adsorption of GQDs onto silica (Si0₂) particles.

Table I:

Table II, shows the effect of concentration on the PL resulting from the process with a silica (Si0₂) carrier. Table II:

Results of the various solvents are shown in Fig. 1: a - H₂0; b - ethanol (EtOH); c - isopropyl alcohol (IPA). The choice of solvent did not change the appearance of the carrier under full visible wavelength range light (Fig. 1A). Substantial photoluminescence (PL) is shown in Fig. IB, with higher intensity PL (and ostensibly greater adsorption) evident in silica particles when the solvent was EtOH (b) and IPA (c) than in water (a).

The effect of the amount of GQDs adsorbed onto the Silica particles, on the measured PL is illustrated in Fig. 2: (a) lOOOOppm; (b) 5000ppm; (c) pure silica (Si0₂).

Fig. S illustrates the observable PL under UV light of samples containing: (a) 625 ppm, (b) 5,000 ppm and (c) 10,000 ppm GQDs. PL by the silica carrier with the adsorbed GQDs was observed at concentrations of 1200 ppm, or a ratio of 1:833 (1/1/ silica/l l/ GQDs). Example 2

GQD-specific adsorption onto surface modified carrier

The GQDs may be modified to be more hydrophobic or more hydrophilic to obtain thermodynamic and/or mechanical compatibility with the polymeric resin. GQDs were dispersed in EtOH and filtered (0.22pm round syringe filter). Dichloride (EDC) and triethylamine (TEA) were added and the activation reaction was performed for BO min. Silica-NH₂ powder was dispersed in the GQDs suspension. The reaction was performed at room temperature (RT) overnight. The obtained material was filtered through 2.5pm filter and washed with ethanol and water and dried on filter. Examples of GQD- specific adsorption appear in Table III.

Table III:

Example 3

Silica-encapsulated GQDs

Silica nanoparticles having a volume average diameter (D₅₀) of 60 nm were used as follows: ammonium hydroxide (NH₄OH) solution and GQDs dissolved in EtOH were added to a reaction vessel containing bare silica particles, followed by the addition of tetraethylorthosilicate (TEOS) to form a silica shell with the GQDs embedded. The encapsulation was carried out for 24 hrs. under constant magnetic agitation at room temperature (RT). Table IV summarizes the results. Table IV:

In sample 2, the reaction (TEOS polymerization to form the silica shell coating) was carried out at RT for 18 hrs.

Example 4

Polyamide (PA) impregnation by increasing/decreasing free volume

A solution of GQDs was added to various solvents under continuous stirring. A thermoplastic polymer Polyamide (PA) in granular form was added and allowed to swell for 12 hrs, at RT. The swelled polymer was washed with the same solvent used to solubilize the GQDs until no fluorescence could be observed at the filtrate. The polymer was then dried in a hot oven (70°C for 2hrs.) to remove solvent traces.

Specifically, GQDs solution was diluted in the solvent configured to plasticize and increase the free volume of the polymer. 1 gr of PA polymer was added to the diluted GQDs solution (10 ml) and allowed to swell under continuous magnetic stirring (2h and 12h at RT). The swelled polymer was washed with acetone three times and dried in hot oven (70°C for 2h) to eliminate the any solvent traces. The effect of swelling time on the photoluminescence is shown in Fig. 4: (a) control - no swelling; (b) 2h swelling; and (c) 12h swelling. Table V shows the observed effect of cosolvent on impregnation of PA with GQDs.

Table V:

Generally, and as shown in Fig. 5A-5B (samples (a)-(i) correspond to AH24a - AH24i of Table V, respectively), more polar solvents (e.g., Ethanol & Methanol) exhibit high relative photoluminescence but reduce the clearness of the polymer in ambient light, while less polar solvents (e.g., dichloromethane (DCM), tetrahydrofuran (THF)) exhibited high photoluminescence without affecting the clearness in the ambient light. Accordingly, the selection of proper solvent can be used to further impart properties on the final product.

Example 5

Impregnation by full dissolution of the polymer polv(methylmethacrylate) (PMMA) in a solvent in the presence of GQDs

As illustrated in Fig. 14, reactor BOO was inerted 604 upon loading of the solvent 310. While stirring, polymer poly(methylmethacrylate) (PMMA) 320 was added and reactor 300 was heated to 50 °C, followed by slow addition of GQDs 330 to the reactor 300 while vigorously stirring. Once a homogeneous mixture was obtained, reactor 300 was cooled to RT. Simultaneously, paddle dryer S50 was inerted 604' and the mixture was transferred 605 to paddle dryer 350. The solvent started being removed by stirring the paddle, building a vacuum of 40-50 mBar and by further heating. The mixture was then cooled to RT, and the solid cake transferred 606 to mill 360 and crushed to the point where a fine powder was obtained. Additional drying can take place in a vacuum oven, or by exposure to desiccants such as silica or phosphorous pentoxide (P₂0₅). The effect of various solvents is described in Table VI.

Table VI:

Results are shown in Figs. 6A and 6B (samples (a)-(j) correspond to AH31a - AH31j of Table VI, respectively), showing complete dissolution in Acetone, tetrahydrofuran (THF), Acetonitrile, and dichloromethane (DCM) (less polar solvents) and the resulting photoluminescence. Similar results were observed with thermoplastic poly(urethane) and are shown in Figs. 7A and 7D, showing GQDs embedded in thermoplastic poly(urethane) (TPU) matrix by comingled dissolution under ambient light (7A left) and 365nm UV light (7A right), with the GQD emission spectra following UV excitation at 350nm shown in Fig. 7B.

Embedding of different color GQDs (in e.g., TPU) can be done and is illustrated in Figs. 8A and 8B: (a) violet, (b) blue, (c) cyan, (d) green, (e) pink, (f) purple, and (g) red, showing GQDs embedded in thermoplastic poly(urethane) (TPU) matrix by comingled dissolution under ambient light (8A) and under EMR excitation at 365 nm UV light (8B).

Figs. 9A and 9B show the process as applied to silicone (PDMS) which can be thermoset after curing. GQDs were embedded in silicone matrix (PDMS) by complete solvent (toluene) dissolution under ambient light (Fig. 9A), with photoluminescence under UV EMR shown in Fig. 9B. It is also possible to mold the silicon and segregate the color of the GQDs top and bottom as shown under ambient light in Fig. 10A and under UV EMR in Fig. 10B.

Example 6

Embedding of fluorescent carbon dots having pattern with different emission wavelengths in epoxy matrix

Fluorescent carbon dots were incorporated onto a starch matrix. The Starch (ACS reagent by Sigma, CAS No. 9005-84-9) was added to the solvent of deionized water (DIW) and heated up to 100 °C under magnetic stirrer until full dissolution was observed. The fluorescent carbon based materials were then added dropwise into the starch solution and allowed to stir 15 min to have a clear solution which exhibited fluorescence under UV (365 nm) flashlight illumination.

The solution was then transferred to a 120 °C oven (equipped with Turbo internal ventilation) to eliminate the solvent (DIW) and obtain a dry solid fluorescent starch. The dry fluorescent starch was then milled to a fine powder. Table VII shows 3 fluorescent carbon dots used. BB

Table VII

The fluorescent starch was dispersed in an epoxy-based resin by adding the fluorescent starch composite to the castable epoxy resin (0.2 gr each color of starch to 20 gr Part A epoxy 324 by Elgad). The hardener (Part B, 10 gr) was added to the mixture followed by hand mixing. The epoxy mixture was degassed and casted into a silicon mold and allowed to cure at RT for 12h before the release from the mold. Results are shown in Fig. 11 under ambient light in (a), (c) and (e) and under 365nm UV light in (b), (d) and (f). In the black samples of Fig. 11 (c)-(f), the procedure is the same except for the addition of black colorant to Part A prior the mixing (UVO BLACK by Smooth-On, l%wt).

Although embodiments of the invention have been described by way of illustration, it will be understood that the invention may be carried out with many variations, modifications, and adaptations, without exceeding the scope of the claims.

Claims

1. A polymeric product comprising a polymer substrate and fluorescent carbon based materials dispersed therein.

2. A product according to claim 1, wherein the fluorescent based materials are selected from: fluorescent carbon dots (CDs), photoluminescent carbon nanostructures (PCNs) or graphene quantum dots (GQDs).

3. A product according to claim 1, wherein the polymeric product is characterized by having uniform fluorescence.

4. A product according to claim 1, wherein the polymeric product is characterized by having patterned fluorescence.

5. A product according to claim 4, wherein the product comprises fluorescent carbon based materials having different emission wavelengths.

6. A product according to claim 1, wherein the polymer substrate is thermoset polymer.

7. The product according to claim 6, wherein the thermoset polymer is selected from: poly(epoxide), an acrylic, poly(dimethylsiloxane) thermoset, poly(urethanes), a copolymer thereof or their combination.

8. A product according to claim 1, wherein the polymer substrate is thermoplastic polymer.

9. The product according to claim 8, wherein the thermoplastic polymer is selected from: Acrylonitrile butadiene styrene (ABS), poly(vinylchloride) (PVC), High density poly(ethylene) (HDPE), Low density poly(ethylene) (LDPE), Poly(propylene) (PP), poly(styrene) (PS), poly(methylmethacrylate) (PMMA), Natural rubber (NR), poly(oxymethylene) (POM), Polycarbonate (PC), Poly(ethylene terephthalate) (PET), poly(etheretherketone) (PEEK), poly(caprolactam) (Nylon 6, PA6), a copolymer thereof, terpolymer thereof, or their combination.

10. A product according to claim 1, which is an identification item.

11. A product according to claim 1, which is an ornamental item.

12. A method for manufacturing a product according to claim 6 or 7, comprising: a. adsorbing fluorescent carbon based materials onto a carrier to form a carrier-fluorescent complex;

b. mixing the carrier-fluorescent complex with a thermoset polymer resin, forming a master batch;

c. optionally, diluting the master batch with thermoset polymer resin; and d. admixing the master batch with the thermoset hardener, thereby initiating curing.

IS. The method according to claim 12, wherein mixing the carrier-fluorescent complex with the thermoset polymer resin is performed at a maximum loading level of between 20-30 %wt of carrier to resin, depending on the carrier and the resin.

14. The method according to claim 12, wherein in step (c) the master batch is diluted with said thermoset polymer to a concentration of between 0.1-5 %wt.

15. A method for manufacturing a product according to claim 8 or 9, comprising: a. adsorbing fluorescent carbon based materials onto a carrier to form a carrier-fluorescent complex; b. mixing the carrier-fluorescent complex with a composition comprising a thermoplastic polymer, under extrusion conditions, forming a master batch; and

c. diluting the master batch with a thermoplastic resin, thereby forming a process batch ready for injection molding.

16. The method according to claim 15, wherein in step (b) the extrusion conditions are at between 200-300 C° and at maximum loading level of 5-10 %wt of carrier to resin.

17. The method according to claim 15, wherein in step (c) the master batch is diluted with a thermoplastic resin to a concentration of between 0.005-1 %wt.

18. The method according to claim 12 or 15, wherein adsorbing fluorescent carbon based materials onto a carrier comprises:

a. solubilizing the fluorescent carbon based materials in a solvent;

b. adding the carrier to the fluorescent carbon based materials solution under continuous mixing;

c. separating the -fluorescent complex from the solvent;

d. drying the carrier-fluorescent complex; and

d. grinding the carrier-fluorescent complex into a fine powder.

19. The method according to claim 12 or 15, wherein adsorbing fluorescent carbon based materials onto a carrier comprises:

a. solubilizing the carrier in a solvent, optionally, under heating conditions;

b. adding the fluorescent carbon based materials to the carrier solution and mixing;

c. drying the carrier-fluorescent complex; and

d. grinding the carrier-fluorescent complex into a fine powder.

20. The method according to claim 19, wherein solubilizing the carrier in a solvent is performed under heating conditions of between 60-80 C°.

21. The method according to claim 18 or 19, wherein drying the carrier-fluorescent complex is done in a vacuum oven at a temperature of between 60-120 C° and between 20-50 mBar.

22. The method according to claim 18 or 19, wherein the carrier is selected from starch, Al₂0₃, Ti0₂, ZnO, Ce0₂, Si0₂, or a combination thereof.

23. The method according to claim 18 or 19, wherein the ratio between the fluorescent carbon based materials and the carrier is between 1:850 and 1:50, or between 100 ppm and 20,000 ppm.

24. The method according to claim 18 or 19, wherein the solvent is selected from: ethanol (EtOH), isopropyl alcohol (IPA), water, or a solvent composition comprising one or more of the foregoing.

25. The method according to claim 12 or 15, wherein the step of mixing the carrier- fluorescent complex is preceded by filtering the carrier-fluorescent complex.

26. The method according to claim 12, wherein curing comprises crosslinking, photocuring, or a curing combination comprising the foregoing.

27. The method according to claim 12, further comprising a step of molding the process batch prior to curing.

28. The method according to claim 15, wherein the step of mixing the master batch with the thermoplastic resin is followed by a step of forming the process batch into pellets, rods, powder or a physical form comprising one or more of the foregoing.

29. A method for manufacturing a product according to claim 8 or 9 by impregnating a thermoplastic polymer with fluorescent carbon based materials comprising:

a. forming a powder comprising composite thermoplastic polymer and the fluorescent carbon based materials;

b. using a first solvent which is thermodynamically compatible with both the thermoplastic polymer and the fluorescent carbon based materials, solubilizing the powder; and

c. removing the first solvent forming a composite powder of thermoplastic polymer and fluorescent carbon based materials.

30. The method according to claim 29, further comprising, washing the powder with a second solvent.

31. The method according to claim 29, wherein the step of forming the composite powder of thermoplastic polymer and fluorescent carbon based materials comprises: a. admixing the thermoplastic polymer into a reactor containing the first solvent, forming a polymer solution;

b. while stirring, admixing the fluorescent carbon based materials into the polymer solution forming composite thermoplastic polymer-fluorescent solution;

c. transferring the composite thermoplastic polymer-fluorescent solution to a dryer;

d. removing the first solvent, forming a coarse cake; and

e. milling the coarse cake, forming a fine powder of composite thermoplastic polymer and fluorescent carbon based materials.

32. The method according to claim 29, wherein the first solvent is selected from: acetone, acetonitrile, tetrahydrofuran (THF), dimethylformamide (DMF), dichloromethane (DCM), or a solvent composition comprising the foregoing.

33. The method according to claim 30, wherein the second solvent is thermodynamically compatible with the fluorescent carbon based materials only.

34. The method according to claim 30, wherein the second solvent is the same as the first solvent.

35. The method according to claim 30, wherein the second solvent is acetone.

36. The method according to claim 29, further comprising flushing the reactor and/or the dryer.

37. The method according to claim 36, wherein flushing is done with an inert gas selected from: Helium, Argon, Nitrogen, or an inert gas composition comprising one or more of the foregoing.

38. The method according to claim 31, wherein the step of admixing the fluorescent carbon based materials is preceded by a step of heating the reactor.

39. The method according to claim 38, wherein the reactor is heated to a temperature of between 50 °C to 100 °C depending on the solvent boiling point.

40. The method according to claim 31, wherein the step of transferring the composite thermoplastic polymer-fluorescent solution to the dryer, is preceded by a step of cooling the reactor to a temperature of between 20 °C and 27 °C.

41. The method according to claim 31, wherein the mill is a hammer mill or a ball mill.

42. The method according to claim 31, wherein the dryer is a paddle dryer and the step of removing the solvent occurs simultaneously with building a vacuum in the paddle dryer.

43. A method for manufacturing a product according to claim 6 by impregnating a thermoset polymer with fluorescent carbon based materials, comprising:

a. forming a thermoset resin to be impregnated with fluorescent carbon based materials;

b. increasing the free volume of a thermoset resin to a point where the average free volume of the thermoset resin is equal to or larger than the average volume of each of the fluorescent carbon based materials;

c. admixing a solution of fluorescent carbon based materials; and d. decreasing the free volume of the thermoset resin to the point where the average free volume of the thermoset resin is smaller than the average volume of each of the fluorescent carbon based materials.

44. The method according to claim 43, wherein the thermoset polymer is selected from: a poly(epoxide), an acrylic, poly(dimethylsiloxane) thermoset, poly(urethanes), a copolymer, terpolymer or a combination thereof.

45. The method according to claim 43, wherein the step of increasing the free volume comprises heating the thermoset resin, exposing the thermoset resin to a thermodynamically compatible plasticizer, decreasing atmospheric pressure, or a combination of the foregoing.

46. The method according to claim 45, wherein the plasticizer is selected from: cycloaliphatic amine, aliphatic amine, toluene, glycol ether-ester, dibutylphthalate (DBP), benzyl benzoate (BnBzO), polyisobutylene (PIB), or a combination thereof.

47. The method according to claim 43, wherein the step of decreasing the free volume comprises cooling the thermoset resin, removing the thermodynamically compatible plasticizer, increasing atmospheric pressure, or a combination of the foregoing.

48. The method according to claim 47, wherein the fluorescent carbon based materials are modified to be soluble in the plasticizer.

49. The method according to claim 43, wherein the step of decreasing the free volume of the resin is followed by washing the thermoset resin with a solvent specific for the fluorescent carbon based materials.

50. The method according to claim 43, wherein the product is a rod, a pellet, or a powder.

51. The method according to any one of claims 12, 15, 29 or 43, wherein the fluorescent carbon based materials are modified to be thermodynamically compatible with the thermoplastic or thermoset polymer.

52. The method according to any one of claims 12 to 51, wherein the polymeric product is an identification item.

53. The method according to any one of claims 12 to 51, wherein the polymeric product is an ornamental item.