Castor oil-based material for the release of biogenic volatile organic compounds for agricultural applications

Abstract

The present invention describes a biodegradable biomass-derived composition for controlled-release of Biogenic Volatile Organic Compounds (BVOCs), said composition consisting of a continuous phase consisting of a crosslinked castor oil-based polymer and a dispersed phase comprising at least one Biogenic Volatile Organic Compound (BVOC), wherein said BVOC is biologically synthesized and effective for improving plant defence response, growth and / or productivity.

Description

[0001] INDUSTRIAL INVENTION PATENT APPLICATION TITLED:

[0002] CASTOR OIL-BASED MATERIAL FOR THE RELEASE OF BIOGENIC VOLATILE ORGANIC COMPOUNDS FOR AGRICULTURAL APPLICATIONS

[0003] FIELD OF THE INVENTION

[0004] The present invention relates to the field of controlled-release of Biogenic Volatile Organic Compounds (BVOCs); in particular it relates to a biodegradable biomass- derived composition for controlled-release of Biogenic Volatile Organic Compounds (BVOCs).

[0005] STATE OF THE ART

[0006] The present agricultural production faces the challenge of meeting the increasing demand for food due to the projected rise in the world population. To address this issue, a new green revolution is necessary. While advancements such as mechanization, genetic progress, and the use of improved crop varieties have led to enhanced grain crop yields, the exploitation of these methods have reached a plateau. Moreover, the extensive use of fossil-based chemicals like fertilizers and pesticides has raised concerns due to their depletion of natural resources, as well as endangered food safety and environmental pollution.

[0007] In this context, the utilization of Biogenic Volatile Organic Compounds (BVOCs) presents a sustainable strategy for implementing smart and sustainable agricultural practices to enhance plant protection and productivity in order to increase food production in an environmentally friendly way. BVOCs belong to a diverse class of biologically generated chemicals with medium to high vapor pressure, playing crucial roles in plant defence signalling and communication. Acting as airborne signals, BVOCs enable rapid defence signalling between distant plant organs and facilitate communication between plants. Furthermore, BVOCs have the ability to prime the defence system of plants, enhancing resistance against upcoming stresses. They can also repel herbivores or attract their natural enemies, such as parasitoids or predators. Plants possess the ability to maintain a memory of previous stress events, which influences their response to future stressful situations. Factors that shape this stress memory, referred to as "priming stimuli," play a crucial role in plant BVOCs. Due to their volatility, plant BVOCs can quickly reach different parts of the plant and contribute to priming. Priming enables a plant to exhibit an earlier, stronger, and faster response when faced with subsequent stress, leading to increased resistance and / or tolerance. BVOCs have been extensively studied for their ability to prime defences against herbivorous insects, pathogens, and environmental stresses. Various BVOCs, such as green leaf volatiles (GLVs) like Z- 3-hexenyl acetate, methyl salicylate (MeSA), monoterpenes (e.g., camphene and pinene), and low concentrations of methyl jasmonate (MeJA), have been found to actively participate in the mechanisms leading to systemic acquired resistance (SAR) or enhanced responsiveness to wounding. Methanol, a volatile compound ubiquitously emitted from plant leaves during cell division and cell wall expansion, has also shown potential as a priming stimulus by enhancing resistance to pathogenic bacteria.

[0008] Following the growing interest in employing new sustainable methods to increase agriculture productivity, several patents have explored the use of specific Volatile Organic Compounds (VOCs) for defending plants against insects, pathogens, and environmental stresses, and for boosting the of plant growth (e.g. , WO2013014316, EP4197330, WO2018146524). At the same time, different strategies have been designed for the controlled release of VOCs, including: a) the preparation of nanostructures, such as microcapsules or emulsions (W02020131151 ), capable of slowly releasing the VOCs but implying complicated synthetic protocols; b) the use of adsorption / desorption devices (CN109092013, GB2563910), which suffer the need of multiple dispenser, and of poor homogeneity in the diffusion of the VOCs; c) the direct use of BVOCs-emitting plants, which can release a few BVOCs and subtract land and nutrients for crops; d) the use of gels (JP2006225289) or polymers (JP2000239104 and JP1999286402), which can be revolutionary if sustainable synthesis and applications can be accomplished. For example, NZ162021 describes the use of PVC (polyvinylchloride) and PVA (Poly(vinyl alcohol)) as carriers for organic phosphorus insecticide. However, the low sustainability and biodegradability of the polymeric networks entails significant limits. WO2015106342 relates to the encapsulation and controlled release of VOCs for increasing the shelf life of perishable products, by preparing fibres composed of pectin, alginate, guar gum, carrageenan, waxy com starch, a surfactant, and VOC(s). The fibres are prepared by mixing the ingredients in solution followed by electrospinning. Yet, the cumbersome synthetic procedure and the utilization of surfactants limits the potentialities of the invention. GR1000706 describes a system for controlled release and diffusion of biologically active volatile substances, comprised of a homogenous solution of an active component in an organic carrier, solid at room temperature and hermetically sealed in a specialised casing. Nevertheless, the use of castings limits the utilization in crops since many castings should be used and collected after utilization.

[0009] As a result, there is a need of developing materials capable of releasing BVOCs during an extended period of time with low environmental impact, low production costs, and biodegradable characteristics.

[0010] DEFINITION AND ABBREVIATIONS!

[0011] BVOC: Biogenic Volatile Organic Compound

[0012] SUMMARY OF THE INVENTION

[0013] It has been surprisingly found that a crosslinked castor oil-based polymer containing a dispersed phase of a single BVOC or a mixture of BVOCs achieve the controlled release of BVOCs addressing the need for environmentally friendly solutions in agriculture.

[0014] Subject matter of the present invention is therefore a biodegradable biomass- derived composition for control led-release of Biogenic Volatile Organic Compounds (BVOCs), said composition consisting of a continuous phase consisting of a crosslinked castor oil-based polymer and a dispersed phase comprising at least one Biogenic Volatile Organic Compound (BVOC), wherein said BVOC is biologically synthesized and effective for improving plant defence response, growth and / or productivity.

[0015] Compared to prior art systems and commercial products, the biomass-derived composition of the invention demonstrated to be more efficient in controlled dispensing of BVOCs for extended periods of time. Moreover, the composition of the invention is biodegradable in soil and / or under light irradiation, making it disposable and capable to be assimilated into the natural environment. This stands in contrast to most current techniques and products. Indeed, the utilization of nonedible castor oil in the crosslinked castor oil-based polymers contributes to their low environmental impact, while their low cost and simple preparation make them advantageous. Sustainable and bio-derived crosslinking agents can also be employed during production.

[0016] The composition of the invention has the potentiality to revolutionize agricultural practices, enhance plant protection, and improve productivity while addressing concerns associated with conventional and already reported approaches. In fact, the composition can be easily prepared on large scale, using environmentally friendly and biologically-derived compounds, and can be placed nearby potted plants into greenhouses, or field crops, without the need to be collected after utilization being biodegradable.

[0017] For an aspect the present invention relates to the use of the above described composition in agriculture as well as in other applications, such as mulch, trellis netting, membranes for cooling / air conditioning systems and heat pumps, anti-hail and shading nets, and coatings.

[0018] For another aspect the present invention relates to a controlled-release agrochemical BVOC formulation comprising or consisting of the biodegradable biomass-derived composition as above described.

[0019] For another aspect the present invention related to an environmental friendly agricultural method of controlling the release of a single BVOC or a mixture of BVOCs effective in improving plant defence response, growth and / or productivity, said method comprising chemically or physically linking said single BVOC or a mixture of BVOCs to a biodegradable biomass-derived crosslinked castor oil-based polymer.

[0020] For another aspect the present invention relates to a method for the agricultural controlled-release of a single BVOC or a mixture of BVOCs, said method comprising dispersing in the air surrounding crops or onto or into the soil a controlled-release agrochemical formulation as above described.

[0021] For another aspect the present invention relates to a method for preparing the composition of the invention, said method comprising:

[0022] A. mixing a castor oil fatty acid or ester, at least one biodegradable crosslinking agent, and at least one BVOC having biological activity in improving plant defence response, growth and / or productivity; B. reacting the mixture of step A) at a temperature in the range from 10 to 150°C. For another aspect the present invention relates to an alternative method for preparing the composition of the invention, said method comprising: a', mixing a castor oil fatty acid or ester, at least one biodegradable crosslinking agent; b'. reacting the mixture of step A) at a temperature in the range from 10 to 150°C; c'. ’adding during the reaction of step b’) and at the end of it at least one BVOC having biological activity in improving plant defense response, growth and / or productivity.

[0023] These methods of preparation of the composition of the invention are simple, efficient, and cost-effective and suitable for scale-up production.

[0024] DETAILED DESCRIPTION OF THE INVENTION

[0025] According to the invention the dispersed phase of a single BVOC or a mixture of BVOCs can be chemically and / or physically linked to the castor oil-based polymer. The BVOCs can be in liquid, solid, or vapor phase. BVOCs can be in the form of essential oils.

[0026] Preferably the single BVOC or mixture of BVOCs is selected in the group consisting of biologically derived alcohols, aldehydes, carboxylic acids, carboxylic esters and terpenes.

[0027] The BVOC is preferably selected in the group consisting of MeOH, benzaldehyde, acetic acid, methyl salicylate, isoprene, caryophyllene, bisabolol, selinene, germacrene, humulene, farnesene, curcumene, bergamotene, zingiberene, valencene, pinene, linalool, geraniol, eucalyptol, citronellol, cymene, cineole, thymol, menthol, hexenal, myrcene, nerol, eugenol.

[0028] These natural-based VOCs can be loaded into the composition either during or after the polymerization phase. The mass ratio of the crosslinked castor oil-based polymer to the BVOC(s) typically ranges between 20:80 to 99.9:0.1 , preferably 95:5. The biomass-derived composition of the invention comprises at least one continuous phase consisting of a crosslinked castor oil-based polymer. Castor oil, derived from non-edible castor beans (Ricinus communis L.), is primarily composed of triglycerides of fatty acids, with ricinoleic acid (cis-12-hydroxyoctadec-9-enoic acid) normally accounting for 82-93% of its composition. Castor oil-based polymers, including polyurethanes, polyesters, polyethers, polyamides, and polysulfides, have been widely used in the polymer industry due to their bio-based nature (Bioresource Technol., 97 (9) 1086, 2006). The advantage of using castor oil-based polymers lies in their low environmental impact, biodegradability, and compatibility with lipophilic properties of many BVOCs (i.e. terpenes) suitable for various agricultural purposes, being involved in plant defence against insects, pathogenic microbes and environmental stresses, as well as enhancing plant growth and productivity. The use of bioderived crosslinking agents further enhance the sustainable features of the material and eventually boost its biodegradable characteristics.

[0029] In the biomass-derived composition of the invention, the crosslinked castor oilbased polymer forms the continuous phase, acting as a net and cage for loading the dispersed phase of BVOCs. The crosslinked polymer is formed by polymerizing a castor oil fatty acid or ester with a biodegradable crosslinking agent capable of forming covalent or ionic bonds with castor oil. This resulting polymer provides mechanical and thermal stability to block and stabilize the dispersed phase, even during the manufacturing process.

[0030] Preferably, said crosslinked castor oil-based polymer is therefore obtained by polymerization of a castor oil fatty acid or ester with a crosslinking agent comprising a functional group selected from: an isocyanate group, a carboxyl group, an anhydride group, an anion group of a carboxylic acid, an amino group, an imino group, an amide group, a sulfonic acid group, an anion group of a sulfonic acid, a methanedithioic acid group, an anion group of a methanedithioic acid, or a mixture thereof. Said crosslinking agent is bioderived and contains in the chemical structure polar groups such as sulfonic acid, phosphate, and sulphates that enhance the biodegradability of the material.

[0031] Preferably, said crosslinked castor oil-based polymer is selected from the group consisting of a polyurethane, a polyester, a polyether, a polyamide, and a polysulfide.

[0032] In a preferred embodiment, the crosslinked castor oil-based polymer is a polyurethane obtained by polymerizing a castor oil fatty acid or ester with poly(hexamethylene diisocyanate), pentamethylene diisocyanate, or 3- (cyclohexylamino)-l -propanesulfonic acid- and 2-ethyl-1 -hexanol-blocked 1 ,5- pentamethylene diisocyanate, or 2-ethyl-1 -hexanol-blocked 1 ,5-pentamethylene diisocyanate, or a mixture thereof. The weight ratio of the castor oil fatty acid or ester to poly(hexamethylene diisocyanate), pentamethylene diisocyanate, 3- (cyclohexylamino)-l -propanesulfonic acid- and 2-ethyl-1 -hexanol-blocked 1 ,5- pentamethylene diisocyanate, or a mixture thereof preferably ranges from 60:40 to 10:90, with 25:75 being more preferable.

[0033] Preferably according to the method of preparation of the composition of the invention, before step B9 or b’) the mixture of step A) or a’) may be shaped or applied onto a substrate, and the reaction can be carried out in sealed container, like cases, bags, bins, cans, to prevent BVOC evaporation.

[0034] Preferably, in said step B) or b’) said reaction is carried out at a temperature in the range from 50 to 90°C.

[0035] The composition of the invention can be used as such or put in a container or applied on a substrate.

[0036] The composition of the invention can be in solid form or in form of a highly viscous liquid which can easily dispersed in the air surrounding crops or onto or into the soil. Preferably, the composition according to the present invention is in form of block, powder, thin film, membrane, pellet, ball, foam, sphere, , sheet, string, paste, honeycomb, bead, mesh, fiber, corrugated sheet, net, or rotor.

[0037] Thus, once placed nearby plants leaves or roots, the composition of the invention may have numerous benefits, including improving plant defence response, growth and productivity. Indeed, slow and continuous release of BVOCs can exert a protective effect against abiotic stressors by quenching the excessive production of reactive oxygen species (ROS) which can damage plant tissues. The continuous release of BVOC by the composition of the invention can also inhibit the germination and growth of plant pathogens, repels herbivores, and attracts herbivore parasitoids. Additionally, exposure of plant to the BVOCs released by the composition of the invention may induce the synthesis of defence proteins and metabolites, such as phytoalexins, which impede microbial colonization. The BVOCs released by the material may also acts as a priming stimulus by inducing epigenetic changes and the accumulation of transcription factors, facilitating faster expression of plant defences. Furthermore, prolonged exposure to BVOCs released by the composition of the invention may interacts with senescence mechanisms and help fights against unwanted weed species by exerting allelopathic effects.

[0038] Throughout the description and subsequent claims, numerical entities expressing amounts, parameters, and percentages are understood to be preceded by the term "about." The ranges of numerical entities encompass both the maximum and minimum values, including all possible intermediate ranges, unless specifically indicated otherwise. Percentages and ratios are calculated by weight unless otherwise stated, and all measurements are performed at 25°C unless specified otherwise.

[0039] The present invention will be better understood in light of the following embodiments.

[0040] EXPERIMENTAL SECTION

[0041] METHODS

[0042] BVOC releasing rate

[0043] The BVOC releasing rate is determined by the exposition of the composition of the invention, loaded with different amount of BVOCs and prepared using different castor oil to crosslinker ratios, to a controlled atmosphere and monitored by weight losses. The releasing rate is reported as an average of the releasing rate measured every day for at least 10 days. The BVOCs releasing rate is reported normalized to the mass of the biomass-derived composition. The biomass-derived cross-linked castor oil based polymer without BVOCs is used as reference.

[0044] BVOC concentration

[0045] The BVOCs concentration is monitored by international standards (such as OSHA PV2199 for acetic acid) also using chromatography analysis (for example, with a GC-MS from PerkinElmer, USA or a PTR--MS analyzer from lonicon, Austria). Degradation in soil burial test

[0046] Soil burial tests are carried out at 30.0 ± 0.1 °C, under moisture-controlled conditions. Triplicate specimens of film samples are placed in darkened vessels containing a multi-layer substrate. Filter paper is used as a positive control. Sample portions of 2 cm x 2 cm are cut. Specimens of film (initial weight 500-700 mg, filter paper ~28 mg; Gibertini Crystal, d = 0.1 mg) are sandwiched between two layers of a mixture of milled perlite (70 g) and commercial soil (200 g), moistened with 100 mL of distilled water. The bottom and top layers are filled with 60 g of perlite moistened with 120 mL of distilled water. Perlite is used for increasing aeration to the soil and the amount of water retained. A flow of moistened air is supplied from the bottom of each vessel every 24 h for 15 min. Samples are removed after regular intervals (30 days), brushed softly, washed with distilled water several times and dried under vacuum in the presence of P2O5 at room temperature, to constant weight. The degree of degradation is evaluated by weight loss (WL) by using the following Equation: WL (%) = (Wi - Wt) / Wi x 100, where Wi is the initial weight of the sample and Wt is the weight after the established time.

[0047] Defence against pathogens

[0048] The protective effect against pathogens is measured by running experiments with the fungus Botrytis cinerea, a pathogen able to infect hundreds of plant species on their aboveground organs (leaves and fruits), in controlled and sealed atmosphere. The experiments are performed with the fungus grown in vitro on appropriate growth medium (potato dextrose agar, PDA), and by using tomato leaves where fungal spores are inoculated.

[0049] BRIEF DESCRIPTION OF THE DRAWINGS

[0050] Fig. 1 Controlled release of VOC ( / .e., isoprene) by the biomass-derived material of the invention as by the two formulations of different texture, soft (material 5A) and dense (material 5B). The release of VOC (i.e., isoprene) is expressed on a volume (Fig. lA) or on mass basis (Fig.1 B) of the material.

[0051] EXAMPLES

[0052] EXAMPLE 1 : controlling the BVOC releasing rate under dynamic conditions

[0053] Different biomass-derived materials were prepared as follow: castor oil (Pharma Quality, Giomavaro Sri, Italy) and poly(hexamethylene diisocyanate) (Covestro SA, Germany) were mixed, in the different ratio reported in Table 1 , in a round flask with a magnetic stirrer for 15 minutes at 20°C. The use of different ratios of castor oil to crosslinking agent resulted in compounds with different rheological properties (the less the crosslinking agent content, the softer and stickier the final material). The mixtures were then divided and mixed with different amount of methyl salicylate, as summarized in Table 1. Methyl salicylate is known as to elicit plant defence and repel herbivores (e.g.in Brassica rapa subsp. chinensis against peach potato aphids, Myzus persicae). The mixtures were then poured into aluminium bags, sealed, and pressed in a mould to obtain foils of 10x10x0.5 cm and cured at 85°C for 24 hours. Samples were thus cut in pieces of 2x2x0.5 cm and placed in a 20 L box under an air flux of 0.1 ml min’1. The BVOC releasing rates were obtained according to the method above detailed and measured on average on fifty days. The results are reported in Table 1.

[0054] References Example 1 Example 1 was repeated without adding any BVOC, to determine the weight losses and adjust the average BVOC releasing rate accordingly.

[0055] Table 1

[0056] *The BVOC releasing rates of the materials without BVOC refer to the weight losses due to moisture naturally present in the castor oil, and other volatile compound in the same oil. Values of average BVOC releasing rate of samples 1 -9 are reported net to those values. EXAMPLE 2: controlling the BVOC releasing rate under static conditions

[0057] Two different biomass-derived materials were prepared as follow: castor oil (Pharma Quality, Giomavaro Sri, Italy) and poly(hexamethylene diisocyanate) (Covestro SA, Germany) were mixed, in the different ratio reported in Table 2, in a round flask with a magnetic stirrer for 15 minutes at 20°C. The mixtures were then divided and mixed with acetic acid corresponding to a ratio of crosslinked castor oil-based polymer to BVOC of 95:5. Acetic acid is a BVOCs capable of enhancing the plants’ tolerance to drought. The mixtures were then poured into aluminium bags, sealed, and pressed in a mould to obtain foils of 10x10x0.5 cm and cured at 85°C for 24 hours. Samples were thus cut in pieces of 1 g each one. Each sample was placed in a 54 L sealed glass reactor. The BVOC concentration was obtained according to the method above detailed.

[0058] References Example 2

[0059] Example 2 was repeated without adding acetic acid.

[0060] Table 2

[0061] EXAMPLE 3: biodegradation in soil

[0062] Different biomass-derived materials were prepared as follow: 82 g of castor oil (Pharma Quality, Giomavaro Sri, Italy) and 18 g of 2-ethyl-1 -hexanol-blocked 1 ,5- Pentamethylene-diisocyanate (Covestro SA, Germany) were mixed in a round flask with a magnetic stirrer for 15 minutes at 20°C. The mixture was then divided into three and mixed with different amount of alpha-pinene, as summarized in Table 3. Alpha-pinene is a BVOCs having allelochemical property and thus growth-inhibitory activity against weeds. The mixtures were then poured into aluminium bags, sealed, and pressed in a mould to obtain foils of 10x10x0.5 cm and cured at 80°C for 24 hours. The BVOC releasing rate and the degradation after soil burial test were obtained according to the methods above detailed. The results are reported in Table 3.

[0063] Table 3 EXAMPLE 4

[0064] A biomass-derived composition according to the invention was prepared as follow: 78 g of castor oil (Pharma Quality, Giomavaro Sri, Italy), 22 g of 3- (cyclohexylamino)-l -propanesulfonic acid- and 2-ethyl-1 -hexanol-blocked 1 ,5- pentamethylene diisocyanate (Covestro SA, Germany) and 1 g of p-cymene were mixed with a magnetic stirrer for 5 minutes at 20°C. p-cymene is a BVOC known to have an antimicrobial activity. The mixtures were then poured into aluminium bags, sealed, and pressed in a mould to obtain foils of 10x10x0.5 cm and cured at 70°C for 24 hours. Samples were thus cut in pieces of 0.5 g each one and placed in a sealable glass vessel in proximity of petri dishes containing PDA medium and an agar plug containing Botrytis cinerea mycelium. After 3 days exposure, the in vitro growth of Botrytis cinerea was completely inhibited (i.e. 100%) as compared to controls (Table 4, Control 1 and Sample 1 ). In another in vivo experiment where Botrytis cinereawas inoculated on tomato leaves, the fungal infection lesions on the leaves were reduced by 100% (Table 4, Control 2 and Sample 2).

[0065] EXAMPLE 5

[0066] Material 5A was prepared as follows: 78 g of castor oil (Pharma Quality, Giomavaro Sri, Italy) and 22 g of 2-ethyl-1 -hexanol-blocked 1 ,5-pentamethylene-diisocyanate (Covestro SA, Germany) were mixed in a round flask with a magnetic stirrer for 15 minutes at 20°C; 100 pl of isoprene were then added. Isoprene is a small lipophilic VOC produced by several plant species and known to protect them from a wide range of abiotic and biotic stresses. The mixture was then poured into aluminium bags, sealed, and pressed in a mould to obtain foils of 10x10x0.5 cm and cured at 85°C for 24 hours.

[0067] Material 5B was prepared by following the same procedure as material 5A, but using 56 g of castor oil (Pharma Quality, Giomavaro Sri, Italy) and 44 g of 2-ethyl-1 - hexanol-blocked 1 ,5-pentamethylene-diisocyanate (Covestro SA, Germany), into which 100 pl of isoprene was added.

[0068] Material 5A resulted softer and less rigid than material 5B, due to a lower formation of polyurethanes. Accordingly, the material 5A is referred to as “soft” in the figure 1 , whereas the material 5B is referred to as “dense”.

[0069] Then, 0.95-1 .52 g (0.8 -1 cm3) of each material were placed in a 22 L flow-through chamber under a continuous nitrogen flux of 1 .5 L min’1at constant temperature of 25°C, in order to simulate the release of VOC in a ventilated greenhouse. The concentration of isoprene was monitored semi-continuously by a gas chromatograph (GC) i which sampled 50 ml of air exiting the chamber every 25 minutes for 6 hours.

[0070] The controlled release of the VOC was then normalized by either the volume (Fig.1 A) or density (Fig. 1 B) of the two different formulations of the biomass-derived material (5A and 5B).

[0071] Regardless of the different texture, both the biomass-derived materials showed a controlled and long-lasting release of the VOC ( / .e., isoprene), reaching a constant rate ( / .e., a plateau) within a few hours. Moreover, on the basis of both the constant release rate of the VOC released (achieved after a few hours) and the amount of VOC ( / '.e. , isoprene) initially loaded into the materials (A and B), it can be estimated that the release of VOC to last in several days and even weeks.

[0072] The different rate of release of VOC by the two materials can be ascribed to the peculiar physicochemical interactions of isoprene with castor oil, rather than the different polymeric mesh which characterizes the materials. Indeed, the less dense the material, the more the amount of castor oil that was used for the preparation, which interacted through higher intramolecular bonds ( / .e., Van der Walls, etc.) with isoprene, thus entrapping this relatively high-vapour-pressure (733.3 hPa at 25°C) VOC and slowing down the release rate. Hence, depending on the different application, it is possible to modulate the release rate of the VOC embedded into the biomass-derived material of the present invention by varying the composition of the material components herein described.

Claims

CLAIMS1. A biodegradable biomass-derived composition for controlled-release of Biogenic Volatile Organic Compounds (BVOCs), said composition consisting of a continuous phase consisting of a crosslinked castor oil-based polymer and a dispersed phase comprising at least one Biogenic Volatile Organic Compound (BVOC), wherein said BVOC is effective for improving plant defense response, growth and / or productivity.

2. The biodegradable composition according to claim 1 wherein said BVOC selected in the group consisting of alcohols, aldehydes, carboxylic acids, carboxylic esters and terpenes.

3. The biodegradable composition according to claim 2 wherein said BVOC selected in the group consisting of MeOH, benzaldehyde, acetic acid, methyl salicylate, isoprene, caryophyllene, bisabolol, selinene, germacrene, humulene, farnesene, curcumene, bergamotene, zingiberene, valencene, pinene, linalool, geraniol, eucalyptol, citronellol, cymene, cineole, thymol, menthol, hexenal, myrcene, nerol, eugenol.

4. The biodegradable composition according to any one of claims 1 -3 wherein said crosslinked castor oil-based polymer is selected from the group consisting of a polyurethane, a polyester, a polyether, a polyamide, and a polysulfide and is obtained by polymerization of a castor oil fatty acid or ester with a crosslinking agent comprising a functional group selected from an isocyanate group, a carboxyl group, an anhydride group, an anion group of a carboxylic acid, an amino group, an imino group, an amide group, a sulfonic acid group, an anion group of a sulfonic acid, a methanedithioic acid group, an anion group of a methanedithioic acid, or a mixture thereof.

5. The biodegradable composition according to claim 4 wherein the crosslinked castor oil-based polymer is a polyurethane obtained by polymerizing a castor oil fatty acid or ester with a cross-linking agent selected in the group consisting of poly(hexamethylene diisocyanate), pentamethylene diisocyanate, or 3-(cyclohexylamino)-l -propanesulfonic acid- and 2-ethyl-1 -hexanol-blocked 1 ,5- pentamethylene diisocyanate, or 2-ethyl-1 -hexanol-blocked 1 ,5-pentamethylene diisocyanate, or a mixture thereof; wherein the weight ratio of said castor oil fatty acid or ester to the crosslinking agent ranges from 75:25 to 15:85.

6. The biodegradable composition according to any one of claims 1 -5 wherein mass ratio of the crosslinked castor oil-based polymer to the BVOC(s) ranges between 20:80 to 99.9:0.1 .

7. The biodegradable composition according to any one of claims 1 -6 which is in solid form or in form of a highly viscous liquid.

8. Use of the composition according to any one of claims 1 -7 in agriculture for improving plant defense response, growth and / or productivity.

9. Use of the composition according to any one of claims 1 -7 as mulch, trellis netting, membranes for cooling / air conditioning systems and heat pumps, anti-hail and shading nets, and coatings.

10. A control led-release agrochemical BVOC formulation comprising or consisting of the biodegradable biomass-derived composition according to any one of claims 1 -7.11 . An environmentally friendly agricultural method of controlling the release of a single BVOC or a mixture of BVOCs effective in improving plant defence response, growth and / or productivity, said method comprising chemically or physically linking said single BVOC or a mixture of BVOCs to a biodegradable biomass-derived crosslinked castor oil-based polymer.

12. A method for the agricultural controlled-release of a single BVOC or a mixture of BVOCs, said method comprising dispersing in the air surrounding crops or onto or into the soil a controlled-release agrochemical formulation according to claim 10.

13. A method for preparing the composition according to any one of claims 1 -7, said method comprising:A. mixing a castor oil fatty acid or ester, at least one biodegradable crosslinking agent, and at least one BVOC having biological activity in improving plant defence response, growth and / or productivity;B. reacting the mixture of step A) at a temperature in the range from 10 to 150°C.

14. A method for preparing the composition according to nay one of claims 1 -7, said method comprising: a', mixing a castor oil fatty acid or ester, at least one biodegradable crosslinking agent; b'. reacting the mixture of step A) at a temperature in the range from 10 to 150°C; c'. ’adding during the reaction of step b’) and at the end of it at least one BVOC having biological activity in improving plant defense response, growth and / or productivity.

15. The method according to claim 14 or 15 wherein before step B) or b’) the mixture of step A) or a’) is shaped or applied onto a substrate, and the reaction is carried out in sealed container to prevent BVOC evaporation.

Images