Masterbatch, process for forming film from hydrophobic polymers with nanostructured reinforcement, and hydrophobic polymer film

Abstract

The present invention relates to a masterbatch, a process for forming film from hydrophobic polymers reinforced with a nanostructured composite, and the film formed by this process, imparting novel properties to the hydrophobic polymer in a sustainable and renewable manner and making it possible to obtain a film using a completely green process.

Description

MASTERBATCH, PROCESS FOR FORMING HYDROPHOBIC POLYMER FILMS WITH NANOSTRUCTURED REINFORCEMENT AND HYDROPHOBIC POLYMER FILM FIELD OF THE INVENTION

[0001] The present invention describes a masterbatch for forming a film of hydrophobic polymers, particularly polyesters, with nanostructured reinforcement, giving the film properties distinct from those of the isolated polymer. The present invention also relates to the film obtained through the masterbatch and process described herein. The present invention falls within the fields of Chemistry and Materials Engineering. BACKGROUND OF THE INVENTION

[0002] Nanocomposites are a class of materials that combine nanoparticles with a matrix of a material, resulting in enhanced properties compared to the individual components.

[0003] Nanocomposites can be made from various materials, such as metals, ceramics, polymers, or carbon-based materials like carbon nanotubes or graphene. They are dispersed throughout the matrix material, which can also be a polymer, metal, ceramic, or even a combination of these.

[0004] The properties of nanocomposites can be tailored by adjusting factors such as the type, size, shape, and concentration of the nanoparticles, as well as the matrix material and processing techniques used to create them. Some of the enhanced properties that nanocomposites can exhibit include mechanical strength, electrical conductivity, thermal conductivity, barrier properties, flame resistance, and optical properties.

[0005] Nanocomposites have applications in various fields, including aerospace, automotive, electronics, energy, medicine, and environmental engineering. Examples include lightweight and strong materials for structural applications, conductive materials for electronics, and materials with barrier properties. Enhanced for packaging. An important application of nanocomposites is in the composition of a masterbatch. A film-forming masterbatch is a specialized type of masterbatch used in the plastics industry, primarily in the production of thin films. These masterbatches contain additives that help improve the film-forming properties of the polymer, such as its ability to spread evenly and form a uniform film during the manufacturing process. These additives can be nanocomposites.

[0006] Despite the versatility and wide range of industrial applications of nanocomposites, there is concern, particularly regarding polymer nanocomposites, about environmental, health, and sustainability issues in their production and disposal. Not all are biodegradable, which can contaminate water bodies, soil, and even the air. Some can bioaccumulate along the food chain and pose health risks to animals and humans. Furthermore, many are primarily derived from fossil fuels, making them dependent on non-renewable resources. Given these challenges, it is necessary to propose alternatives that mitigate all these inherent risks of polymer nanocomposites through the use of materials produced via green routes and that provide environmental safety.

[0007] An additional challenge is encountered in the composition of nanocomposites comprising hydrophobic polymers. Although some biodegradable hydrophobic polymers such as Polyglycolic Acid (PGA) and Poly(ethylene adipate) (PEA), recyclable ones such as Polyethylene Terephthalate (PET), and those of renewable origin such as Poly(lactic acid) (PLA) and Polyhydroxyalkanoates (PHAs) already exist, the addition of renewable-source reinforcements to form nanocomposites with these polymers is not trivial due to compatibility issues.

[0008] It is worth highlighting at this point that one of the most interesting nanostructured reinforcements for the formation of polymer composites of a specific nature... Nanocellulose is a renewable material that is increasingly being used as a filler due to its unique properties and environmental sustainability. Derived from cellulose, the most abundant organic polymer on Earth, nanocellulose refers to cellulose particles that have been broken down into nanometric dimensions.

[0009] Chemically, like its macroscopic counterpart (cellulose), nanocellulose possesses an inherent polarity due to its chemical structure. Cellulose is a linear polymer composed of repeating units of [3-D-glucose] linked by [3-1,4] glycosidic bonds. Each glucose unit contains hydroxyl groups (-OH) attached to carbon atoms, which contribute to its polarity. These hydroxyl groups can form hydrogen bonds with water molecules and other polar substances, giving nanocellulose hydrophilic properties.

[0010] Given the polarity opposition between hydrophobic polymers and nanocellulose, several compatibilization strategies have been adopted. For example, documents CN1 15926397, CN1 13512280, and CN1 16444958 propose polymer composites reinforced with nanocellulose, in which the surface hydroxyl groups are modified to become hydrophobic through reactions such as esterification or alkylation, making them compatible with the polymer. In these cases, the reactions themselves can generate waste or use non-renewable and environmentally unfriendly reagents, compromising the goal of obtaining a green and safe composite.

[0011] Alternatively, patents CN1 13337013 and CN104672825 propose dispersing the hydrophobic polymer in organic solvents such as chloroform, acetonitrile, acetone, tetrahydrofuran, methanol, or ethanol, then incorporating nanocellulose and forming a film by removing the solvent. Strategies like these have the same drawback of generating potentially environmentally impactful waste, just as in cases where nanocellulose is chemically modified.

[0012] Document CN1 1 1138719 proposes mixing nanocellulose with adjuvants such as kaolin, talc, starch, and carbonate. This proposal involves coating nanocellulose with calcium carbonate nanospheres, in a process that involves the adsorption of sodium hydroxide to the nanocellulose in an aqueous medium and calcination of the embedded product. It also includes a plasticizer to make the mixture compatible with hydrophobic polymers for the formation of a film by melting processing. This is a proposal with many components, which may hinder its economic viability, but also a costly energy process for the production of the nanostructured reinforcement. The process involves the formation of a liquid suspension of nanocellulose, the dispersion of additives in the suspension, and drying at room temperature or under heating, followed by grinding and sieving of the resulting material. Document CN1 15991894 presents a similar proposal by coating nanocellulose with calcium carbonate nanospheres, in a process that involves the adsorption of sodium hydroxide to the nanocellulose in an aqueous medium and calcination of the embedded product.

[0013] Document KR10-2022-0097341 presents a composite comprising nanocellulose, specifically from rice husk, combined with polymers such as polybutylene adipate-co-terephthalate (PBAT) and polylactic acid (PLA), or both. The composite material may be in pellet form, preferably PBAT-nanocellulose pellets in a ratio of 95:5 to 99:1, which, according to the document, would have good dispersibility in PBAT. The document explains that, due to the cohesive force present in the preparation of a PBAT-only film containing less than 1% by weight or no nanocellulose, the agglomeration phenomenon may be increased, thus making its preparation impossible. However, no indication is given on how nanocellulose and PBAT are compatibilized to form the pellet, or whether the distribution of nanocellulose throughout the film is, in fact, uniform, given that they are materials with opposite polarities.As is known to a technician in the field, despite numerous research studies regarding the incorporation of nanocellulose into composites, several problems still exist in its incorporation into these compositions. The main problems are related to the dispersion of the nanocellulose, resulting in agglomeration and lack of homogeneity of the system, which in turn cause losses of properties. physical and / or chemical properties of the materials. The problem of incorporating nanocellulose becomes even more pronounced when using cellulose nanocrystals (CNCs), due to their high tendency to agglomerate, because they have a structure with strong hydrogen bonds due to the presence of hydroxyl groups in the CNC.

[0014] Similarly, in CN1 16925398, micro-nanocellulose with a water content of 60-90% by weight is uniformly mixed with thermoplastic polymer particles in a closed environment. The mixture is subsequently dried to obtain mixed thermoplastic polymer particles coated with micro-nanocellulose. WO2023 / 1501 10 provides a process for producing latex or polymer masterbatches and particulates, in which the compounds are wet homogenized, centrifuged, and passed through a screw mixer for further water removal to form the nanocomposite.

[0015] Patent BR 10 2022 006457 1 describes a nanostructured particulate of natural rubber latex (LBN) and cellulose nanocrystals (CNC) whose water removal from suspension occurs through lyophilization. In this patent, the formation of ice crystals during the process allowed the formation of a new particulate configuration, in which LBN and CNC were compatibilized. This particulate was able to form transparent films with starch and hydrophilic polymers, possessing good compatibility with this polymeric class. In this case, the main challenge was to reduce the hydrophilicity of the formed film, and the CNC particles coating the LBN allowed the LBN to become compatible with this environment.

[0016] Given the above, it is observed that the work of obtaining a hydrophobic polymer film, especially a biodegradable one of renewable origin, reinforced with nanostructured particles that also have this characteristic, is a significant challenge. More particularly, considering that nanocellulose is one of the best candidate nanoparticles for this purpose and that its opposite polarity hinders its compatibility with the hydrophobic polymer of interest, it is a challenge to make it compatible through processes that are easily... Scalable to bring to market a thin film with the right properties from an environmental point of view. BRIEF DESCRIPTION OF THE INVENTION

[0017] The present invention solves the problems of the prior art by incorporating natural rubber latex (LBN) particles coated with cellulose nanocrystals (CNC) into hydrophobic polymers, particularly polyesters. These nanostructured particles are made by homogenizing LBN and CNC in an aqueous medium, followed by solvent removal through lyophilization. As disclosed in patent BR 10 2022 006457 1, the lyophilized nanostructured particulate was able to form transparent films with starch and hydrophilic polymers.However, it was not expected that these same particles, in the same configuration, would be able to disperse uniformly and impart unique properties to hydrophobic films as well, proving to be fully compatible with them and providing a solution for the homogeneous dispersion of CNC with the hydrophobic medium via a dry method, without the need for organic solvents, chemical modification of CNC, or the inclusion of other additives to the medium.

[0018] Surprisingly, through processing techniques such as extrusion and hot melting, nanocellulose becomes uniformly dispersed throughout the polymer, capable of forming a thin film with transparency, a high degree of water vapor barrier, and greater tensile strength and strain at break, making the films less anisotropic in relation to their stretching direction. These characteristics allow hydrophobic polymers to form films applicable, for example, to packaging, without losing their hydrophobic, biodegradable, renewable, and environmentally friendly properties, adding properties that make the film more malleable, resistant to traction, and more easily formable.

[0019] In this sense, the present invention relates to a masterbatch for the production of a thin film of hydrophobic polymer, in which the masterbatch comprises LBN particles coated with CNC by lyophilization and a hydrophobic polymer, particularly a polyester, a thin film obtained with the masterbatch and the production process of said film. BRIEF DESCRIPTION OF THE FIGURES

[0020] The following figures are presented:

[0021] Figure 1 shows the production flowchart of the masterbatch and its processing in the co-rotating extruder for the formation of planar films based on PBAT.

[0022] Figure 2a presents an illustrative diagram showing the longitudinal (L) and transverse (T) stretching axes of PBAT-based films after exiting the planar die coupled to the extruder. Figure 2b shows the PBAT-based planar film produced from its stretching, demonstrating its homogeneity and transparency.

[0023] Figure 3 shows the stress-strain curve of PBAT-based films produced from their masterbatch. The formulations contain 0.25% CNC / LBN relative to the total mass of the nanocomposite.

[0024] Figures 4a and 4b show, respectively, the longitudinal (ORL) and transverse (ORT) tensile strength of PBAT-based films produced from their masterbatch. Figures 4c and 4d show, respectively, the longitudinal (ERL) and transverse (ERT) tensile strength of PBAT-based films produced from the masterbatch. The symbol “*” means that there is a statistically significant difference (p > 0.05) for the same particulate concentration range compared to pure PBAT. The notation “ns” means that there is no statistically significant difference (p > 0.05) for the same particulate concentration range compared to pure PBAT.

[0025] Figure 5a shows the system containing the water-filled support sealed with the film on top for water vapor permeability rate (WVTR) analysis. Figure 5b presents the WVTR data for the PBAT formulations obtained from the masterbatch.

[0026] Figure 6 shows the micrographs obtained by microscopy. Scanning electron microscopy (SEM) of cryogenic fracture of PBAT-based films in the transverse direction of film stretching with the following formulations varying inversely the mass proportion of LBN relative to the mass proportion of CNC: (a) PBAT, (b) PBAT_CNC (c) PBAT_CNC_1 LBN, (d) PBAT_CNC_5LBN, and (e) PBAT_CNC_10LBN, wherein all formulations presented contain 0.25% mass percentage of nanostructured particulate matter relative to the total mass of the nanocomposite. The microscopies indicate the dispersion and distribution of the nanostructured particles throughout the PBAT matrix.

[0027] Figure 7a illustrates the thermogravimetric analysis (TGA) curves of the PBAT formulations. Figure 7b shows the curves derived from the thermogravimetric analysis (DTG). These curves indicate the mass loss and mass loss rate, respectively, as a function of temperature, indicating material degradation events. The formulations have 0.25% CNC / LBN relative to the total mass of the nanocomposite.

[0028] Figure 8 presents the differential scanning calorimetry (DSC) analyses of the PBAT-based film formulations. In the first heating (Figure 8a), the thermal history of the films is clearly observed, highlighting the effects of processing and formulation. The cooling (Figure 8b) and second heating (Figure 8c) events reflect the thermodynamic events dependent exclusively on the film formulation, with controlled cooling and heating rates. In the curves of the first heating (Figure 8a), the deflection around -30 °C represents the glass transition temperature (T g) of the films. Two melting events are also observed in these curves: the first peak, around 55 °C, is related to the melting of the crystalline part of butylene adipate, and the second peak, around 125 °C, to the melting of the remaining crystalline part of PBAT. In the cooling curve (Figure 8b), the peak corresponding to the exothermic recrystallization event of the material stands out. In the second heating curve (Figure 8c), the deflection corresponding to T is again observed. g of the films, followed by a single endothermic event related to the melting of the material. The hatched areas correspond to the enthalpy of fusion (AHm), when endothermic, or the enthalpy of recrystallization (AHR), when exothermic. The formulations have 0.25% CNC / LBN in relation to the total mass of the nanocomposite. DETAILED DESCRIPTION OF THE INVENTION

[0029] In a first embodiment, the present invention relates to a masterbatch. A masterbatch is defined as a composition comprising one or more additives in high concentration, used in segments of the plastics processing industry to impart other properties to plastics during the manufacturing process. The masterbatch of the present invention is characterized by comprising a hydrophobic polymer and a nanostructured reinforcement, wherein said reinforcement is a natural rubber latex (LBN) particle coated with cellulose nanocrystals (CNC) by lyophilization. The main advantage of using this masterbatch is the ease and efficiency in dispersing these nanostructured particles in the polymer matrix through thermoplastic routes, resulting in a homogeneous final product. Furthermore, the masterbatch allows for precise dosing and facilitates the handling of additives.

[0030] The hydrophobic polymer can be, in particular, from the class of polyesters. Specifically, the hydrophobic polymer can be chosen from the group that includes biodegradable and / or renewable polymers, such as PBAT, PLA, and polycaprolactone (PCL). Particularly, it is preferable that the hydrophobic polymer be PBAT.

[0031] The nanostructured reinforcement of natural rubber latex (LBN) coated with cellulose nanocrystals (CNC) by lyophilization can be obtained as follows: a) prepare an aqueous suspension with a concentration of 1% (w / v) to 4% (w / v) of dry mass of cellulose nanocrystals (CNC); b) add to the suspension obtained in step “a”, from 0.5% to 10% by mass, relative to the mass of CNC, of ​​natural rubber latex (LBN); c) freeze the mixture obtained in step “b”; d) freeze-dry the material obtained in step “c”; e) micronize the material obtained in step “d”.

[0032] It is observed that the nanostructured reinforcement is made up of two renewable and abundant raw materials in nature without the use of any type of chemical reagent other than water, which validates the application of these nanostructured particles in the most diverse areas where solvent exudation can be a problem. An example of this is food packaging.

[0033] In this regard, the nanostructured reinforcement of the present invention comprises 90% to 99.5% by mass of CNC and 0.5% to 10% by mass of LBN, and the masterbatch of the present invention has a nanostructured reinforcement load between 0.25% and 5.0%.

[0034] In a second embodiment, the present invention relates to a process for forming a hydrophobic polymer film with nanostructured reinforcement, characterized by comprising the steps of: a) Preparing a nanostructured reinforcement, wherein said reinforcement is a natural rubber latex (LBN) particle coated with nanocellulose (CNC) by lyophilization; b) Providing a masterbatch comprising a hydrophobic polymer and the nanostructured reinforcement of step (a); c) Grinding the masterbatch; d) Extruding the masterbatch with a planar die; e) Obtaining a film.

[0035] In step (a), the reinforcement can be prepared in accordance with that described in paragraph

[0031] of this report.

[0036] In accordance with the first embodiment of the present invention, the hydrophobic polymer of the masterbatch in step b) may be, in particular, from the class of polyesters. In particular, the hydrophobic polymer may be chosen from the group comprising biodegradable polymers, such as PBAT, PLA and PCL. Particularly, it is preferable that the hydrophobic polymer be the PBAT. The nanostructured reinforcement of the present invention comprises 90% to 99.5% by mass of CNC and 0.5% to 10% by mass of LBN, and the masterbatch of the present invention has a nanostructured reinforcement load between 0.25% and 5.0%.

[0037] Step b) is preferably performed using a high-shear homogenizer of the drais type, thus allowing the nanostructured reinforcements to be added to the polymer matrix, ensuring their better dispersion and distribution in final processing routes such as planar die extrusion for film formation.

[0038] Step c) of grinding is preferably carried out in a knife mill for comminution of the masterbatch, for its subsequent insertion into thermoplastic routes, such as extrusion.

[0039] Step d) can be performed using any extruders known to a technician in the field. In particular, when the hydrophobic polymer is PBAT, extrusion should be carried out at a temperature between 120 and 140 °C, adjusting the extruder's temperature profile within this range.

[0040] The film obtained in e) can be applied, for example, to food packaging and sealing films.

[0041] It is a third embodiment of the present invention, therefore, a film characterized by comprising a hydrophobic polymer and a nanostructured reinforcement, wherein said reinforcement is a natural rubber latex (LBN) particle coated with cellulose nanocrystals (CNC) by lyophilization.

[0042] Similarly to previous embodiments, the polymer can be, in particular, from the class of polyesters, especially chosen from the group comprising biodegradable materials, such as PBAT, PLA, and PCL, with PBAT being preferred. The nanostructured reinforcement of the present invention comprises 90% to 99.5% by mass of CNC and 0.5% to 10% by mass of LBN, and the nanostructured reinforcement load in the film ranges from 0.25% to 5.0%.

[0043] The film of the present invention apparently has a high degree of It offers visual transparency, better deformation and higher tensile strength in the longitudinal direction, and less anisotropy than the film formed with the pure polymer, while maintaining its hydrophobic properties. Examples

[0044] This description refers to a PBAT-based masterbatch containing CNC-coated LBN nanostructured particulates and its production process, as shown in Figure 1.

[0045] The production of all PBAT film formulations through processing in a co-rotating extruder was successful, using a planar die followed by stretching of the films by a rotating roll, as illustrated in Figure 2a. The mechanical properties of the PBAT films were investigated under tension, both in the longitudinal (L) and transverse (T) directions of stretching, in order to observe the effect of processing on the final film properties. The films showed a high degree of transparency and homogeneity, as shown in Figure 2b for the PBAT_CNC_10LBN@F0.25 formulation.

[0046] Mechanical analysis of the films under tension revealed viscoelastic behavior. The presence of CNC / LBN nanostructured particulates resulted in an apparent increase in yield strength and tensile strength, as illustrated in Figure 3.

[0047] The analysis of the mechanical properties of the films was performed in both the longitudinal and transverse directions, as illustrated in Figure 4. Figures 4a and 4b show the tensile strength in the longitudinal (ORL) and transverse (ORT) tensile directions of the films. It is observed that the addition of films containing CNC-coated LBN resulted in a significant improvement in the tensile properties of the films. The greater amount of LBN contributed to the improvement in mechanical properties, suggesting a possible compatibility between CNC and the PBAT matrix through the LBN. Furthermore, the mechanical properties in the transverse direction were inferior to those in the longitudinal direction. However, the addition of CNC-coated LBN particles provided a The tensile strength improved, reducing the anisotropy of the films, as indicated in Figure 4b. Figures 4c and 4d present the analysis of the specific strain at rupture in the longitudinal (ERL) and transverse (ERT) directions, respectively. It is observed that the specific strain at rupture increased with the addition of LBN to the PBAT formulation in both directions. This behavior suggests that the films became less anisotropic with respect to strain at rupture when LBN particles are added along with CNCs.

[0048] To evaluate the physical properties of water vapor barrier of PBAT-based films, a water vapor permeability test (WVTR) of the formulations was performed, as illustrated in Figure 5a. Figure 5b presents the WVTR results, demonstrating that the maximum concentration of LBN in the CNC / LBN particle formulation resulted in greater resistance to water vapor permeation of the PBAT films. Compared to pure PBAT and the PBAT_CNC_1 OLBN formulation, these already show low WVTR values ​​compared to polysaccharides (-100 g / m³). 2 .h) and other biodegradable polymers such as PCL (-33 g / m³) 2 .h), as well as competitive values ​​when compared to polyolefins, such as polypropylene (PP) (-8 g / m³). 2 .h).

[0049] The morphology of the cryogenic fracture was analyzed to elucidate the mechanical and physical properties of PBAT-based films containing 0.25% particulate mass relative to the nanocomposite mass. Figure 6 illustrates the dispersion and distribution of nanostructured particulates along the PBAT matrix according to the variation in LBN. It was observed that formulations with only CNC (Figure 6b) or with a low amount of LBN (Figure 6c) showed slight heterogeneity compared to the pure PBAT matrix (Figure 6a), evidenced by the possible agglomeration and lack of compatibility of the nanostructured particulates with the PBAT matrix. In contrast, Figures 6d and 6e show that formulations with a higher amount of LBN demonstrated homogeneity similar to that of the pure PBAT matrix (Figure 6a), indicating good dispersion. and distribution of CNC / LBN nanostructured particulates, in addition to high compatibility with the PBAT matrix.

[0050] With the aim of analyzing the thermal properties of the materials, the thermal stability of PBAT-based films was investigated, as illustrated in Figure 7. All formulations showed thermal stability above 300 e C at its first degradation temperature, as illustrated by both the TGA curves (Figure 7a) and the DTG as a function of temperature (Figure 7b). Regardless of the addition of nanostructured particulates or variations in LBN concentration, no significant changes were observed in the thermal stability of the composites, indicating their potential application in food packaging.

[0051] Figure 8 shows the DSC analyses of the PBAT formulations. Apparently, the addition of nanostructured particulates did not interfere with the T gof the PBAT films, for both the first and second heating, as illustrated in Figures 8a and 8c, respectively. However, the addition of nanostructured particulates apparently interfered with the hatched area of ​​the AHm (Figures 8a and 8c) and the AHR (Figure 8c) of the PBAT films. For a better understanding, Table 1 presents the T data. g , Tm, AHm, AHR and crystallinity (X c ) of PBAT films calculated from the theoretical enthalpy for 100% crystalline PBAT (AHo = 1 14 J / g)

[0052] Table 1 - Data from T g , Tm, AHm and AHR extracted from the DSC curves and the calculation of Xcdos PBAT films. First Warm-up Tg (°C) T ml (°C) AH ml (J / g) T m2 (°C) AH m2 (J / g) X c (%) PBAT -29.4 52.8 0.80 124.6 5.13 5.2 PBAT_CNC -31.7 55.6 0.74 124.7 12.70 11.8 PBAT_CNC_1LBN -31.4 56.0 1.49 125.0 11.86 11.7 PBAT_CNC_5LBN -31.3 56.6 1.21 125.4 12.60 12.1 PBAT_CNC_10LBN -31.3 56.0 1.01 122.8 11.66 11.1 Cooling Tc (°C) AH R (J / g) Xc (%) PBAT 104.6 8.36 7.3 PBAT_CNC 101.9 8.81 7.7 PBAT_CNC_1LBN 104.6 7.23 6.3 PBAT_CNC_5LBN 87.1 9.24 8.1 PBAT_CNC_10LBN 98.6 7.84 6.9 Second Warm-up Tg (°C) T m3 (°C) AH m3 (J / g) Xc (%) PBAT -33.9 131.7 3.24 2.8 PBAT_CNC -34.1 128.8 5.07 4.4 PBAT_CNC_1LBN -32.4 129.7 3.77 3.3 PBAT_CNC_5LBN -32.6 125.0 7.15 6.3 PBAT_CNC_10LBN -33.0 129.1 5.16 4.5

[0053] The addition of CNC / LBN nanostructured particulates did not alter the T values. g However, this addition influenced the values ​​of AHm, AHR, and Xc, with the PBAT_CNC_5LBN formulation showing the highest enthalpy and Xc values. cThese values ​​suggest that the CNC_5LBN particulate may have acted as a nucleation point for crystals in PBAT, thus improving mechanical properties (Figures 3 and 4). Furthermore, SEM images (Figure 6) of the cryogenic fracture of the film indicate that these nanostructured particulates are well dispersed and distributed in the PBAT matrix, corroborating the possibility of them acting as nucleation points for crystals uniformly throughout the PBAT films, as indicated by the DSC curves and the AH and X values. c Thus, the methodology for formulating PBAT masterbatch using a high-shear mixer of the drais type proves to be highly viable for the production of hydrophobic matrix-based films with CNC-coated LBN nanostructured reinforcement, giving the film properties distinct from those of the isolated polymer.

Claims

CLAIMS 1. Masterbatch characterized by comprising a hydrophobic polymer and a nanostructured reinforcement, wherein said reinforcement is a natural rubber latex (LBN) particle coated with nanocellulose (CNC) by lyophilization.

2. Masterbatch, according to claim 1, characterized in that the hydrophobic polymer is a polyester.

3. Masterbatch, according to claim 1, characterized in that the hydrophobic polymer is selected from the group comprising PBAT, PLA and PCL.

4. Masterbatch, according to claim 1, characterized in that the hydrophobic polymer is PBAT.

5. Masterbatch, according to claim 1, characterized in that the nanostructured reinforcement comprises 90% to 99.5% by mass of CNC and 0.5% to 10% by mass of LBN.

6. Masterbatch, according to claim 1, characterized by having a nanostructured reinforcing filler between 0.25 and 5.0%.

7. A process for forming a hydrophobic polymer film with nanostructured reinforcement, characterized by comprising the steps of: a) Preparing a nanostructured reinforcement, wherein said reinforcement is a natural rubber latex (LBN) particle coated with nanocellulose (CNC) by lyophilization; b) Providing a masterbatch comprising a hydrophobic polymer and the nanostructured reinforcement from step (a); c) Grinding the masterbatch; d) Extrude the masterbatch with a planar die, ee) Obtain a film.

8. Process according to claim 7, characterized in that step (a) comprises the steps of: a) preparing an aqueous suspension with a concentration of 1% (w / v) to 4% (w / v) dry mass of cellulose nanocrystals (CNC); b) adding to the suspension obtained in step “a”, from 0.5% to 10% by mass, relative to the mass of CNC, of ​​natural rubber latex (LBN); c) freezing the mixture obtained in step “b”; d) lyophilizing the material obtained in step “c”; e) micronizing the material obtained in step “d”.

9. Process according to claim 7, characterized in that the hydrophobic polymer of the masterbatch in step b) is, in particular, of the polyester class.

10. Process, according to claim 7, characterized in that the hydrophobic polymer is chosen from the group comprising PBAT, PLA and PCL, preferably PBAT.

11. Process, according to claim 7, characterized in that the nanostructured reinforcement comprises 90% to 99.5% by mass of CNC and 0.5% to 10% by mass of LBN.

12. Process, according to claim 7, characterized in that the masterbatch has a nanostructured reinforcing filler between 0.25 and 5.0%.

13. Film characterized by comprising a hydrophobic polymer and a nanostructured reinforcement, wherein said reinforcement is a natural rubber particle (LBN) coated with nanocellulose (CNC) by lyophilization.

14. Film characterized by the fact that the polymer belongs to the polyester class.

15. Film characterized by the fact that the polymer is chosen from the group comprising PBAT, PLA and PCL, preferably PBAT.

16. Film characterized by the fact that the nanostructured reinforcement comprises 90% to 99.5% CNC by mass and 0.5% to 10% LBN by mass.

17. Film characterized by the fact that the nanostructured reinforcement load is between 0.25 and 5.0%.

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