Biomass modified polyvinyl alcohol polymers and methods

Abstract

A modified PVOH polymer comprises a hydrophobic modification with a triglyceride seed oil, or a hydrophilic modification with a lactate or an amino acid, as well as a process for producing the same.

Description

PCT Application Attorney Docket No. SSCSRA023PCTBIOMASS MODIFIED POLYVINYL ALCOHOL POLYMERS AND METHODSCROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority to U.S. Provisional Application No. 63 / 603,882 filed November 29, 2023, the entire contents of which are hereby incorporated by reference.BACKGROUND

[0002] The present disclosure relates in general to polyvinyl alcohol (PVOH) polymers and formulations, and more particularly, to biomass modified PVOH polymers having improved properties and methods of creating such polymers.

[0003] All of the subject matter discussed in this Background section is not necessarily prior art and should not be assumed to be prior art merely as a result of its discussion in the Background section. Along these lines, any recognition of problems in the prior art discussed in the Background section or associated with such subject matter should not be treated as prior art unless expressly stated to be prior art. Instead, the discussion of any subject matter in the Background section should be treated as part of the inventor’s approach to the particular problem, which in and of itself may also be inventive.

[0004] PVOH is a common synthetic polymer used in numerous industrial applications including but not limited to papermaking and packaging, protective coatings and films, adhesives, thickening agents, and textiles. PVOH is a versatile polymer with numerous advantages, including water solubility, film forming ability, adhesive properties (e.g., good adhesion and tackiness), biocompatibility, thermal stability, optical clarity, and chemical resistance.

[0005] PVOH is often modified to create improved polymers having diverse chemical and physical properties depending on the needs of each industrial application. Modification may include but is not limited to copolymerization with co-monomers to create copolymers or terpolymers of PVOH or grafting of the PVOH polymer with other compounds. Typically, these co-monomers and compounds used to modify PVOH are derived, whether directly or indirectly, from petrochemical based feedstocks.

[0006] However, many industries are promoting the creation of eco-friendly products, including trying to avoid or at least minimize reliance on petrochemical based feedstocks to reduce carbon impact and waste streams. Part of this effort involves the identification of alternative feedstocks deemed environmentally friendly yet cost effective.

[0007] Accordingly, it would be desirable to identify eco-friendly feedstocks that are not only chemically compatible with PVOH modification, but also result in PVOH polymer chemistries and properties suitable for use in numerous industrial applications where petrochemical based feedstocks are currently in use. Ideally, such feedstocks should be synthesized with PVOH using methods that are efficient, commercially scalable, and with minimal waste and overall environmental impact.BRIEF SUMMARY

[0008] This summary is provided to introduce a selection of concepts that are further described below in the detailed description. This summary is not intended to identify key or essential features of the claimed subject matter, nor is it intended to be used as an aid in limiting the scope of the claimed subject matter.

[0009] In one aspect, a modified PVOH polymer comprises hydrophobic modification with a triglyceride seed oil.

[0010] In another aspect, a modified PVOH polymer comprises hydrophilic modification with a lactate or amino acid.

[0011] Other technical features may be readily apparent to one skilled in the art from the following figures, descriptions, and claims.BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

[0012] FIG. l is a schematic diagram of a solvent and unreacted feedstock recovery process according to the present disclosure.

[0013] FIG. 2 is a schematic diagram of a process to synthesize a modified PVOH according to the present disclosure.

[0014] FIG. 3 is a schematic diagram of a process to synthesize a modified PVOH according to the present disclosure.

[0015] FIG. 4A is a chemical structure diagram of a modified PVOH with ester or amide attachments according to the present disclosure.

[0016] FIG. 4B is a chemical structure diagram of structures derived from seed oils according to the present disclosure.

[0017] FIG. 4C is a chemical structure diagram of example feedstocks according to the present disclosure.

[0018] FIG. 5 is a graph showing the effect of NaOAc loading on the viscosity of hydrophobically modified PVOH polymer according to the present disclosure.

[0019] FIG. 6 is a graph showing the effect of cook time at temperature and cool down time vs. product viscosity of hydrophobically modified PVOH according to the present disclosure.

[0020] FIG. 7 is a graph showing low shear viscosity versus concentration of hydrophobically modified PVOH according to the present disclosure.

[0021] FIGS. 8A and 8B are graphs showing high shear viscosity profiles of hydrophobically modified PVOH according to the present disclosure.

[0022] FIG. 9 is a graph showing low shear viscosity versus hydrophobe loading for hydrophobically modified PVOH according to the present disclosure.

[0023] FIG. 10 is a graph showing viscosity versus temperature for hydrophobically modified PVOH according to the present disclosure.

[0024] FIG. 11 is a photo showing purified hydrophobe feedstocks and their related chemical structures according to the present disclosure.

[0025] FIG. 12 is a graph of low shear associative thickening viscosity drift over time for hydrophobically modified PVOH according to the present disclosure.

[0026] FIG. 13 A is a DSC thermogram for PVOH substrate.

[0027] FIG. 13B is a DSC thermogram for stearate modified PVOH according to the present disclosure.

[0028] FIG. 14 is an FTIR spectrum of hydrophobically modified PVOH according to the present disclosure.

[0029] FIG. 15 shows Hl NMR spectra of canola oil FAME (top) versus FAME modified PVOH (bottom) according to the present disclosure.

[0030] FIG. 16 is a DSC thermogram of hydrophilic modified PVOH according to the present disclosure.

[0031] FIG. 17 shows spectroscopic analysis and chemical structure diagrams of hydrophilic modified PVOH according to the present disclosure.

[0032] FIG. 18 shows a C13 NMR spectrum and chemical structure diagrams of the same compounds of FIG. 17.

[0033] FIG. 19 is a photo showing a reaction product of hydrophilic modified PVOH according to the present disclosure.

[0034] FIG. 20A shows spectroscopic analysis and chemical structure diagrams of hydrophilic modified PVOH according to the present disclosure.

[0035] FIG. 20B shows a C13 NMR spectrum and chemical structure diagrams of the same compounds of FIG. 20 A.

[0036] FIG. 21 shows thermograms of two DSC traces of hydrophilic modified PVOH according to the present disclosure.

[0037] FIG. 22 shows photos of reaction products of hydrophobically modified PVOH according to the present disclosure.

[0038] FIG. 23 are graphs showing a quantitative C13 NMR spectral comparison of hydrophilic feedstocks according to the present disclosure.

[0039] FIG. 24 are thermograms showing hydrophilic modified PVOH versus hydrophilic feedstocks.

[0040] FIG. 25 A shows pH versus reaction time for a hydrophilic modified PVOH according to the present disclosure.

[0041] FIG. 25B shows a titration curve for a hydrophilic modified PVOH according to the present disclosure.

[0042] FIG. 26 is a graph of measured surface tension of hydrophobically modified PVOH according to the present disclosure.

[0043] FIG. 27 is a photo showing results of oil resistance testing of paper coated with hydrophobically modified PVOH according to the present disclosure.

[0044] FIG. 28 is a photo of a reaction product of hydrophilic modified PVOH versus unmodified PVOH according to the present disclosure.DETAILED DESCRIPTION

[0045] The present disclosure provides novel compositions and methods for producing modified PVOH resins using readily available biomass-based feedstocks. These novel modified PVOH resins were surprisingly found to exhibit improved physical properties suitable for a wide range of industrial applications, while being produced using methods that are commercially scalable and with minimal environmental impact, as described further herein.

[0046] In one aspect, a modified PVOH polymer comprises hydrophobic modification with seed oil derived biomass feedstocks. Hydrophobic groups derived from triglyceride seed oils may be used to modify the structure of PVOH homopolymers, as well as PVOH containing amine functionality, including but not limited to vinyl amine modified PVOH such as Ultiloc 5003 provided by Sekisui Specialty Chemicals America, LLC. Such modifications with triglyceride seed oils produce polymers with novel compositions and properties imbued by the hydrophobic modification. The compositions are novel because they are dictated by the composition of the seed oil (or a mixture of seed oils) and by their distribution on the substratepolymer. Further, their production is novel, as described in further detail herein, because it employs a solvent matrix that makes the polymer substrate and the hydrophobe compatible and allows for many types of catalysts to promote the transesterification reaction that produces the polymer. The resulting modified polymers have properties useful in several applications including but not limited to surface tension modifiers, barrier films, low coefficient of friction films, associative thickeners for personal care and construction products, and improved biodegradation.

[0047] In another aspect, a modified PVOH polymer comprises hydrophilic modification with lactate or amino acids. Using hydrophilic molecules derived from plant biomass as feedstocks, the structure of PVOH and PVOH containing amine functionality may be modified by grafting this biomass onto the PVOH backbone through ester or amide linkages. These modifications significantly change the solubility, thermal properties, tensile / elastic properties, and charge distribution on the substrate polymers, particularly with respect to PVOH having amine functionality such as Ultiloc 5003. Further, the composition of the resulting modified PVOH polymers are novel.

[0048] With respect to modified PVOH polymers comprising hydrophobic modification with seed oil derived biomass feedstocks, it is typically difficult to get hydrophobic materials blended or reacted with PVOH and its copolymers because they are not compatible. What is generally done is to react hydrophobes modified with functional groups that are highly reactive to the hydroxyl group on PVOH. However, it was surprisingly discovered that using readily available native seed oils or their methyl ester derivatives as feedstock, and reacting PVOH via a solution or suspension based trans-esterification reaction using DMSO / t-BuOH as a solvent matrix and a suitable esterification catalyst, could yield PVOH with hydrophobic modifications. While reaction yields may be low in some cases for some seed oil feedstocks, the materials are recyclable in the process. Hence, though it is known that transesterification reactions can in principal be used to modify PVOH, they are not generally the reaction path of choice but seed oil biomass offers this opportunity.

[0049] Using the techniques of the present disclosure, a wide range of seed oil types can be used and the seed oil and PVOH (or copolymer thereof) can be made compatible in a reaction mixture. Examples of suitable seed oil triglycerides include but are not limited to canola oil; castor oil; coconut oil; soy bean oil; and methyl ester (FAME) derivatives of seed oil. Examples of suitable PVOH resins include but are not limited to partially or fully hydrolyzed grades of PVOH homopolymers such as Selvol 125, 325, 107, 103, and 523, as well as vinyl amine copolymers of PVOH such as Ultiloc 5003, all of which are available from Sekisui Specialty Chemicals America LLC. Suitable PVOH degree of hydrolysis as measured by13CNMR may be in the range from about 65% to about 99% in some embodiments; or in the range from about 75% to about 95% in other embodiments.

[0050] Seed oil modified PVOH compositional novelty may also be imparted by the techniques of the present disclosure in relation to not only the loading levels achieved (e.g., as controlled by wt% or mol % loading level in the reaction), but also the fact that the polymer products come directly from seed oils or their methyl ester (“biodiesel”) derivatives and all common triglyceride type seed oils are enabled by these techniques. In other words, the modified polymers are derived from a source of “impure” hydrophobes whose structure is dictated by the selection of seed oil and whose placement or compositional distribution on the substrate PVOH polymer dictates both compositional novelty and properties. Compositional novelty of the hydrophobe modified PVOH may result from and also be controlled by factors including but not limited to: distribution of unsaturation; quantity of unsaturation; distribution of C chain length; OH groups in the side chain (castor oil); cis-geometry in double bonds; and N attachment to the polymer backbone via amide.

[0051] Additionally, the technique of introducing hydrophobes into PVOH copolymers such as Ultiloc 5003 via amine functionality is a novel approach, and there appears to be a significant property difference (e.g., viscosity) when using the seed oil vs. its FAME derivative in the resulting modified PVOH. Advantages of the techniques of the present disclosure include but are not limited to direct use of commercially available seed oils or their methyl ester derivatives (FAME), recyclability of the reaction components (solvent matrix, seed oils), and no additional derivatization to make hydrophobe sources more reactive with PVOH.

[0052] The resulting seed oil modified PVOH polymers provide many surprising and improved properties suitable for industrial applications, including but not limited to remarkable associative thickening properties in water, as well as surface tension modifiers for water, performance in oxygen barrier films, and oil resistance in paper coatings. Resulting properties of the biomass-modified PVOH polymers are described in further detail herein with respect to the Experimental Methods and Examples.

[0053] With respect to modified PVOH polymers comprising hydrophilic modification with lactate or amino acids, it is typically challenging to efficiently modify PVOH in a simple reaction. The most typical route to copolymers is to copolymerize a suitable monomer. However, to make copolymers with complex pendent groups is challenging by that methodology and to make them from existing biomass-based molecules is virtually impossible without some chemical modification of such molecule. It was surprisinglydiscovered that PVOH homopolymers (such as described above) may be grafted with hydrophilic biomass-based molecules using a simple, one step reaction, and the low yields can be compensated for by the recovery and recycling of the components of the reactions. Further, it was also discovered that modification of PVOH having amine functionality, such as Ultiloc 5003, may be accomplished in water without chemically modifying the biomass feedstocks and resulting in virtually quantitative conversions.

[0054] Using the techniques of the present disclosure, the resulting hydrophilic modified PVOH polymers from biomass feedstocks possess compositional novelty and unique properties by virtue of the molecules whose structural features are already present after biomass extraction so that minimal or no additional chemical modifications are necessary. One-step chemical modifications of the PVOH substrate are enabled by using methyl ester derivatives of amino acids and lactic acid, leaving the biomass molecules structurally intact, e.g., features such as chirality are carried into the modified polymer product. Traditionally, modifications of PVOH are done with either highly reactive feedstocks or by modifying the structure of the PVOH itself, but the techniques of the present disclosure require neither of these manipulations and result in a more efficient process that preserves the unique compositional character of the biomass feedstock.

[0055] Advantages of this process include the fact that the modification of the PVOH amine containing copolymer, such as Ultiloc 5003, can be done by heating in water, and with no catalyst and no precipitation solvent. The water is evaporated off to leave the modified polymer, and the overall process results in surprisingly high conversion yields. However, a DMSO / t-BuOH solvent matrix, without NaOAc or any other catalyst will also work well. Further, the modifications of PVOH homopolymers may be done using DMSO and precipitation solvents that are easily recoverable and recyclable in the process. For example, a solution based trans-esterification reaction using DMSO / t-BuOH as a solvent matrix and a suitable esterification catalyst such as sodium acetate may be used.

[0056] Examples of suitable hydrophilic biomass feedstocks include but are not limited to (S)-methyl lactate; L-lactide; (S)-glutamic acid-5-methyl ester; (S)-glutamic acid- 1 -methyl ester; (S)-aspartic acid-4-methyl ester; and (S)-aspartic acid- 1 -methyl ester. The mirror image isomers could be used as well as mixtures of the stereoisomers. Other amino acids modified with a methyl ester functional group may also be used. Examples of suitable PVOH resins include but are not limited to partially or fully hydrolyzed grades of PVOH homopolymers such as Selvol 125, 325, 107, 103, and 523, as well as vinyl amine copolymers of PVOH such as Ultiloc 5003, all of which are available from Sekisui Specialty Chemicals America LLC. Suitable PVOH degree of hydrolysis as measured by13C NMR may be in the range from about65% to about 99% in some embodiments; or in the range from about 75% to about 95% in other embodiments.

[0057] The resulting hydrophilic biomass-modified PVOH polymers provide many surprising and improved properties suitable for industrial applications, including but not limited to dramatically enhanced water solubility of the lactate modified polymers, and varied thermal properties, such as melting point shifting to lower temperatures and the glass transition to higher temperatures depending upon the polymer substrate. Resulting properties of the biomass-modified PVOH polymers are described in further detail herein with respect to the Experimental Methods and Examples.

[0058] PRODUCTION METHODS

[0059] Production of modified PVOH polymers having hydrophobic modification with seed oil derived biomass feedstocks.

[0060] A typical organic solvent matrix process for moderate to high molecular weight PVOH modification with seed oil derived biomass feedstock is as follows: 5 g Selvol 125 (Hydrolysis, mole% 99.65 + / - 0.35, 4% Solution Viscosity of 4% aqueous solution at 20°C, cP 30.00 + / - 2.00 from Sekisui Specialty Chemicals America LLC), or other appropriate PVOH homopolymer is dissolved in 95 g dry DMSO at 80-85°C. At this scale, magnetic stirring on hot plate is adequate. To this hot solution, seed oil or seed oil FAME dissolved in 20 g t-BuOH is dripped into the solution at about 5 mL / minute. The amount of seed oil depends upon the targeted loading level. Typically 0.5 to 20 mol % is the loading range. At this point, 0.20-1.0 g of anhydrous sodium acetate is added, presumably to catalyze the reaction. The loading level affects the final properties of the polymer. After stirring 6-24 hours at 80-85°C, the reaction is cooled and the polymer precipitated into acetone or ethanol or a mixture of methanol / methyl acetate (solvents readily available from current PVOH manufacturing processes). The precipitated polymer is dissolved or suspended at about 10 wt% in hot water and the polymer again precipitated into acetone or ethanol. At this point, a wash with hexane may be done to remove residual seed oil. After drying at 70°C overnight, the polymer is ready for analytical or application testing.

[0061] A typical organic solvent matrix process for PVOH copolymers of vinyl amine, such as Ultiloc 5003 from Sekisui Specialty Chemicals America LLC, is the same as above for homopolymers of PVOH, except using 10 g of polymer in 90 g of DMSO, and no sodium acetate addition.

[0062] A process for recovering, separating and recycling all solvents and unreacted seed oil feedstock back into the reaction process may involve the steps shown in the flowchart ofFIG. 1. However, it is possible to keep the t-BuOH in the process, though the flow chart of FIG. 1 operates under the assumption it was evaporated out. Further, this flowchart may be operated or cycled multiple times, such as two or three times, before considering the purity of DMSO or adding more hydrophobe feedstock.

[0063] A water-based reaction process may also be followed according to the following: pre-cook seed oil in water with PTS A catalyst. Add solution of about 10 wt% PVOH in water. Cook several hours at 100°C, remove water, and concentrate polymer in reaction mixture. Precipitate polymer “latex” from water as described above.

[0064] Production of modified PVOH polymers having hydrophilic modification with lactate or amino acids.

[0065] The examples below are the same for amino acid biomass. Substitute the amino acid methyl ester where the methyl lactate is used.

[0066] Synthesis of lactate modified PVOH homopolymers such as Selvol 125 involves the following process, and for PVOH copolymers of vinyl amine, such as Ultiloc 5003, may follow the same process except without using NaOAc. A flowchart example of this process is also shown with respect to FIG. 2. 10 g (0.227 mol) of Selvol 125 is dissolved in 90 g of DMSO at 80-90°C. The DMSO is 99+% purity and stored over molecular sieves. Any residual water in the Selvol is not rigorously removed. This solution is kept at 80°C with overhead stirring during addition of 23.63 grams ( 0.227mol) of methyl lactate. The reaction should turn bright yellow. Next, 1.0 g of anhydrous sodium acetate is added to the reaction, and the reaction is maintained at 80°C, for at least 5 hours. After cooling, sometimes overnight if needed, the modified polymer is precipitated into a stirring non-solvent such as acetone. Some precaution is warranted with the choice of non-solvent since the modified polymer exhibits some solubility (or emulsion) in methanol, ethanol, or mixtures of these with DMSO or water. The precipitated polymer is oven dried, typically no more than 75°C, and then dissolved into about 250 g of de-ionized water, usually brought to boiling. This cooled solution or mixture is again precipitated into acetone.

[0067] Synthesis of lactate modified PVOH having amine functionality, such as Ultiloc 5003, using a water matrix involves the following process, such as also shown in the flowchart of FIG. 3. 50 g of Ultiloc 5003 is dissolved in 283 g of water at 80-90°C. The water is from a Millipore de-ionizing system with filtering through a 0.2 micron filter. This solution is kept at 65-70°C during addition of 1.83 g (10 mol %) of (S)-methyl lactate. The reaction is maintained at 65-70°C, typically overnight. The reaction starts with a pH over 10 but after several hours of reaction the pH is near 7, indicating the amino groups are converting to amidegroups. The reaction is then poured into a plastic (e.g., polypropylene) pan and the water evaporated off in an oven at 70-75°C. There is no need to precipitate the polymer into a nonsolvent. Both the glutamate and lactate modified Ultiloc 5003 exhibit some solubility in water mixtures with acetone, methanol, or ethanol. Yields are quantitative.

[0068] EXPERIMENTAL EXAMPLES AND RESULTS

[0069] Reactions of Selvol 125 and Ultiloc 5003 (polymer substrates) with ester- functionalized feedstocks derived from plant-based biomass are herein disclosed. Specifically, the biomass feedstocks are triglyceride seed oils or their fatty acid methyl ester (FAME) derivatives, (S)-methyl lactate, y-methyl-L-glutamate (or (S)-5-methyl glutamate), and a-methyl or P-methyl aspartate. The biomass molecules form pendent groups on the substrate chain through ester or amide bonds. The reactions are carried out in DMSO or water processes, depending upon the feedstock. Basic property changes exhibited by the modified polymers, such as associative thickening in water, melting point and glass transition shifts, and improved water solubility are herein disclosed.

[0070] Materials

[0071] All chemicals were used “as-received”, with the exception of a few batches of Ultiloc 5003 that were purified by repeated reflux and filtering from MeOH to remove residual base and other polar impurities. DMSO was a high purity grade, stored over 4A molecular sieves. Water was from the Milli-Q IV7010 high throughput, reverse osmosis, de-ionizing / filtering system.

[0072] Characterization

[0073] Polymers and other feedstocks were characterized by FTNMR, FTIR, DSC, and viscosity. Other qualitative or semi-quantitative observations are described as necessary.

[0074] FTNMR: Bruker Ascend 400 MHz using Top Spin 4.1.4 analysis software. Spectra collected on polymers were performed on 4 wt% solutions using DMSO-D6 with scans and delay times adequate for quantitative analysis of the spectra unless otherwise noted. For hydrophobically modified samples, the loading level for the hydrophobe was determined by comparing the peak area from the terminal methyl group to the peak area of the methine CH in the polymer substrate backbone.

[0075] FTIR: Bruker Invenio S using OPUS 8.5 analysis software. Spectra were usually collected on films obtained by drying water from 4 wt% solutions used in viscosity measurements. FTIR data reported here are qualitative.

[0076] DSC: TA Instruments Q20 using Q Advantage data collection software and TA Universal 4.5.0.5 analysis software. Typical DSC trace: 1st heat: 10 oC, 30-250 oC; 1st cool, 5 oC, 250-30 oC; 2nd heat, 10 oC, 30-250 oC.

[0077] Viscosity: Brookfield DV-II+ Pro or LV viscometer; Hercules HI Shear dv TEN viscometer using WinShear 32 analysis software. Measurement were made on 4 wt% aqueous solutions at 20°C. For the Brookfield measurements, spindle selection and rpm settings (shear rate) were selected to keep the measurement on-scale, typically the SC4-18, SC4-31, or SC4- 31 spindles were used. For the Hercules measurements, bob “E” was used in the shear rate range of 500-2250 sec-1.

[0078] Film Solubility Test: This test was done by drawing down 10 wt % water solutions of the samples, drying at 80°C for about 30 minutes, then transferring to a humidity-controlled lab at 50 % relative humidity for several hours. The film thickness was measured with a caliper, cut and mounted on a 35 x 45 mm plastic film frame. These films were submerged in 500 mL of water stirring with a constant vortex at 23.5°C. The time for the film to bow or break from the frame, disintegrate (break into pieces), and dissolve were measured.

[0079] Cobb / Mazola Test Method to assess oil and great resistance: A water absorption apparatus, made by TMI model 61-04 Cobb Sizing Tester was used for the test method, which is described as follows according to TAPPI T 441, water absorptiveness of sized (non- bibulous) paper, paperboard, and corrugated fiberboard (Cobb test). The test utilized a 10 square centimeter cylinder and 10ml of 120°C heated corn oil. Test was performed in an oven set at 120°C oven for a duration of 15 minutes.

[0080] OTR (oxygen barrier) test: Films from 10-15 wt% solutions of the polymer were cast onto a BOPP support film and the oxygen barrier tested on a MOCON OX-TRAN oxygen permeation analyzer instrument at 0-90% relative humidity at ambient temperature.

[0081] Surface tension measurement: Measurements were done on the Kruss KI 00 instrument. Solutions were prepared at 0.2 wt.% for surface tension measurement. For pH adjustment, before any measurement, the glass container of the tensiometer was properly rinsed with DI water and filled to approximately 50ml. DI water surface tension at 20°C for calibration check is tested; (Surface tension of DI water at 20°C is 72.80 mN / m). The test solution that was conditioned to 20°C will then be tested after calibration check if finished. A Wilhelmy plate is used to check for surface tension by taking 5-10 readings for each measurement and then the software calculates the average. After each test the Wilhelmy plate is washed with DI water and an Argon torch is used to burn any residues from previous tests as any contamination may affect the reading and give false results.

[0082] Ninhydrin reaction: Ninhydrin is a chemical that reacts with amines, especially amino groups in a-amino acids, and gives a blue color complex, a positive test for the presence of an amino acid. A small portion (less than 0.1 grams) of sample was dissolved or suspended in a couple of mL of water, pH adjusted with a drop of caustic, and a spatula tip of ninhydrin added. Sometimes heating is required but a positive test will yield a blue-purple solution or, in the case of a polymer that may not be dissolved completely or precipitates with pH adjustment, a blue-purple solid.

[0083] Synthesis Examples

[0084] The common thread in the reactions with Selvol 125 and Ultiloc 5003 is either a transesterification or an amidation reaction with methyl ester derivatives of biomass molecules. Two different processes were investigated, one using a DMSO / t-BuOH mixture, the other de-ionized water. Reactions with the amine group of Ultiloc 5003 were not catalyzed. Reactions involving Selvol 125 were catalyzed with NaOAc or PTSA.

[0085] The reactions described here are specific examples but the following should be noted: 1) The substrate polymers may be PVOH or PVOH acetate copolymers from 85-100% hydrolysis of the acetate group, and PVOH copolymers with free amino group, such as Uliloc 5003; 2) the t-butanol co-solvent is preferred but may be substituted with another tertiary alcohol or other solvent that is both compatible with DMSO and dissolves the desired hydrophobe feedstock; 3) the ratio of t-BuOH to DMSO is adjusted to keep the polymer and hydrophobe compatible, either soluble or intimately blended, the adjustments are made according to amount of hydrophobe added and the molar mass of the polymer, the latter being an important consideration for maintaining the solubility of the polymer; 4) the hydrophobe feedstocks may be derived from any seed oil triglyceride or its fatty acid ester, especially methyl ester, derivative; 5) the amino acids may be any type that include a reactive ester, especially methyl ester, functional but exclude a functional group that may compete with the desired polymer modification reaction; 6) the catalyst most often used was various loadings of sodium acetate, but any number of well-known metal cation esterification catalysts or sulfur based acid catalysts such as sulfuric acid or p-TSA may be employed here.

[0086] Synthesis of fatty acid methyl esters (FAME) from triglyceride seed oil.

[0087] A 2 liter separatory funnel was charged with 1 liter of seed oil and 250 mL of a 1.5 wt % solution of NaOH in methanol, dried over molecular sieves. This mixture was shaken until a persistent emulsion formed. After standing overnight, two liquid phases formed, the non-polar FAME layer on top and the polar methanol layer on bottom. The methanol layer contains the glycerin by-product, residual NaOH, and other polar impurities. After drainingoff the lower layer, the FAME layer was washed with saturated NaCl solution and again with water. The FAME was then dried over anhydrous sodium sulfate and stored over molecular sieves. Yield may be considered quantitative, structural features of FAME were verified with Hl and C13 FTNMR and FTIR. Suitable FAMES include but are not limited to canola, soy, corn, castor, coconut, which contains an abundance of saturated C8-C12 hydrophobes. The other FAME products are typically mixtures of C18 hydrophobes with varying degrees of unsaturation.

[0088] Selvol 125 modification with hydrophobe.

[0089] DMSO process: 5 grams of Selvol 125 were dissolved in 95 grams of DMSO at 80- 90°C. The DMSO was 99+% purity and stored over molecular sieves. Any residual water in the Selvol was not rigorously removed. This solution was kept at 80°C during addition of 1.67 grams (5 mol %) of canola oil FAME dissolved in 20 grams of t-butanol. This solution is dripped in slowly to minimize or avoid precipitation of the polymer. If small amounts of the polymer precipitate, it will re-dissolve quickly. Next, 0.25 grams of anhydrous sodium acetate were added to the reaction, either as a solid or suspended in about 20 grams of DMSO. The reaction was maintained at 80°C, typically 6-8 hours. After cooling, sometimes overnight, the modified polymer was precipitated into a stirring non-solvent. Methanol, ethanol, and acetone work but it was found that a 50:50 mixture of methanol: methyl acetate works well. As these solvents are by-products of the Selvol production, they are preferred. The precipitated polymer was oven dried, typically no more than 75°C, and then dissolved or suspended into about 100-150 grams of de-ionized water, usually brought to boiling. This cooled solution or mixture was again precipitated into a non-solvent. 75:25 mixture of methanol: methyl acetate works, but acetone or ethanol are also good non-solvents for aqueous solutions of the polymer product. Ideally the non-solvent should be suitable to remove DMSO, t-BuOH, NaOAc, and especially unreacted FAME. Yields were typically not quantitative but spectroscopic analysis and viscosity measurements indicated that the hydrophobic modification was successful.

[0090] Water process: Several iterations of this reaction were attempted. This example appeared to be most productive in terms of hydrophobically modifying Selvol in water. In this example Selvol 325 was used as polymer substrate (Viscosity of a 4% aqueous solution at 20°C 30.00 + / -2.00 cP, Degree of Hydrolysis Mol % 98.40 + / - 0.40, available from Sekisui Specialty Chemicals America LLC). 10 grams of Selvol 325, 10 grams of canola oil FAME, and 1 gram of p-toluene sulfonic acid (PTS A) were combined in 100 g of de-ionized water in an open, 8 oz jar with overhead stirring. The solution was brought to a boil and allowed to evaporate over several hours. After cooling overnight, approximately 50 % of the water had evaporated, leaving a semi-insoluble slurry. Unreacted FAME separated and was easy todecant (about 7 grams). The slurry was precipitated into ethanol, the recovered polymer dissolved in about 150 grams of water (boiling) and the pH adjusted to 7 using concentrated NaOH. This solution was precipitated into acetone, dried, leaving about 9 grams of polymer. Viscosity measurement of a 4 wt% solution in water indicated a reaction, 42.70 +-1.00 cP vs. 25.00 +-1.00 cP for Selvol 325.

[0091] Selvol 125 modification with lactate or glutamate.

[0092] Reaction with glutamate is similar to this example. 10 grams (0.227 mol) of Selvol 125 were dissolved in 90 grams of DMSO at 80-90 °C. The DMSO was 99+% purity and stored over molecular sieves. Any residual water in the Selvol was not rigorously removed. This solution was kept at 80 °C with overhead stirring during addition of 23.63 grams (0.227mol) of methyl lactate. The reaction turned bright yellow. Next, 1.0 gram of anhydrous sodium acetate was added to the reaction. The reaction was maintained at 80°C, for about 5 hours. After cooling, sometimes overnight, the modified polymer was precipitated into a stirring non-solvent such as acetone. The precipitated polymer was oven dried, typically no more than 75°C, and then dissolved or suspended into about 250 grams of de-ionized water, usually brought to boiling. This cooled solution or mixture was again precipitated into acetone.

[0093] Ultiloc 5003 modification with hydrophobe. DMSO method.

[0094] 10 grams of Ultiloc 5003 were dissolved in 90 grams of DMSO at 80-90 °C. The DMSO was 99+% purity and stored over molecular sieves. Any residual water in the Ultiloc was not rigorously removed. This solution was kept at 80°C during addition of 0.67 grams (1 mol %) of canola oil FAME dissolved in 20 grams of t-butanol. This solution was dripped in slowly to minimize or avoid precipitation of the polymer. If small amounts of the polymer precipitated, it re-dissolved quickly. No sodium acetate was added to this reaction. The reaction was maintained at 80°C, typically 6-8 hours. After cooling, sometimes overnight, the modified polymer was precipitated into a stirring non-solvent. Methanol, ethanol, and acetone work but it was found that a 50:50 mixture of methanol: methyl acetate works well. As these solvents are by-products of the Selvol production, they are preferred. The precipitated polymer was oven dried, typically no more than 75°C, and then dissolved or suspended into about 100-150 grams of de-ionized water, usually brought to boiling. This cooled solution or mixture was again precipitated into a non-solvent. 75:25 mixture of methanol: methyl acetate works, but acetone or ethanol are also good non-solvents for aqueous solutions of the polymer product. Ultimately the non-solvent should be suitable to remove DMSO, t-BuOH, NaOAc, and especially unreacted FAME.

[0095] Ultiloc 5003 modification with hydrophobe. Water method.

[0096] 15 grams of Ultiloc 5003 were dissolved in 85 grams of water, heated to near boiling in an 8-ounce jar. At about 85°C, a solution of 1.05 grams (1 mol%) of canola oil FAME in 50 grams of t-BuOH were added. However, other lower alcohols that are solvents for seed oils and water soluble would work (e.g, ethanol, propanol, isopropanol). The mixture was stirred about 22 hours at 75°C. It was only slight cloudy, certainly well dispersed. Over this time, most of the t-BuOH was allowed to evaporate. The reaction mixture developed significant cloudiness indicating that either the modified polymer was insoluble in water or unreacted FAME was separating. After cooling, the polymer was precipitated into acetone. The dried polymer was taken up in about 100 grams of water (about 13 wt% polymer), pH adjusted to ~7-8. The mixture was very cloudy but precipitated again into acetone after cooling. A 4 wt % aqueous solution was prepared for viscosity measurement; it was soluble, very little cloudiness observed. Another version of this reaction involves refluxing the solvent mix, minimizing solvent evaporation during the reaction time. This helps keep the hydrophobe compatible / soluble in the whole course of the reaction.

[0097] Ultiloc 5003 modification with lactate or glutamate.

[0098] Reaction with glutamate is similar to this example. 50 grams of Ultiloc 5003 were dissolved in 283 grams of DMSO at 80-90°C. The water was from Millipore de-ionizing system with filtering through a 0.2 micron filter. This solution was kept at 65°C during addition of 1.83 grams (10 mol %) of (S)-methyl lactate. The reaction was maintained at 65°C, typically overnight. The reaction started with a pH over 10, but after several hours of reaction the pH is near 7, indicating the amino groups were converted to amide groups. The reaction was then poured into a plastic (e.g., polypropylene) pan and the water evaporated off in an oven at 70-75 °C. There is no need to precipitate the polymer into a non-solvent. Both the glutamate and lactate modified Ultiloc exhibit some solubility in water mixtures with acetone, methanol, or ethanol. Yields were quantitative. Spectroscopic analysis indicated that the modification was successful.

[0099] Molecular Structure Targets

[0100] The structures shown in FIGS. 4A - 4C represent the targets of the side chain modifications described in this disclosure. The group R1 in FIG. 4A comes from transesterification or amidation of Selvol 125 or Ultiloc 5003 with the molecules in FIG. 4B or 4C. FIG. 4A shows Selvol 125 and Ultiloc 5003 substrates with ester or amide attachments illustrated. FIG. 4B shows Cl 8 FAME structures derived from triglyceride seed oils. FIG. 4C shows example methyl ester feedstocks of lactate, glutamate, and aspartate. In FIGS. 4Band 4C, the methyl ester is ostensibly replaced with an ester or amide attachment to polymer backbone as shown in FIG. 4A.

[0101] Results and Discussion

[0102] PVOH homopolymer - Selvol modifications.

[0103] Modification with hydrophobes derived from seed oil and seed oil FAMES: Reaction Process Variables.

[0104] The synthetic strategy for the modification of Selvol with seed oil or its FAME derivatives involves selecting a solvent matrix that is compatible for both the polar PVOH and the non-polar hydrophobe molecule. DMSO is known to be a good solvent for PVOH over a broad temperature range but does not dissolve seed oils or FAMEs. The addition of t- BuOH accomplishes the task of making the hydrophobe and the DMSO solution of PVOH compatible, with the DMSO:t-BuOH combination serving as a co-solvent matrix. Solubility studies indicate the limits of the DMSO:t-BuOH ratio capable of maintaining solubility of the PVOH and the hydrophobe. Solubility here means a visual observation of clarity. Visually clear solutions, with no indication of polymer precipitation or cloudiness due to hydrophobe insolubility, were deemed “compatible”. DMSO solutions of Selvol 125 or 165 should be nominally 5 wt% to ensure effective precipitation after reaction. TABLE 1 summarizes the DMSO:t-BuOH ratios that maintain PVOH solubility using the synthesis example described further above, and shows the estimated limit of solubility of PVOH in DMSO:t-BuOH mixtures at 70°C. Addition of the hydrophobe will decrease the PVOH solubility but this was not an issue in the concentration ranges used to modify the PVOH.TABLE 1‘Initial condition: 9.5 wt% solution of PVOH in DMSO at 70° C.

[0105] The catalyst for the transesterification reaction was anhydrous sodium acetate (NaOAc). Though NaOAc is already present in the Selvol as a by-product of the hydrolysis of PVAc, additional quantities were added to the reaction to determine its effect. Reactionswere run identically except for variation of NaOAc quantity. FIG. 5 shows the effect of NaOAc loading on viscosity of Selvol 125 hydrophobically modified polymer, reaction conditions: 5 wt% Selvol in DMSO; 5 mol% FAME hydrophobe in t-BuOH (16 wt % in reaction); 80°C; 8 hours; cool down overnight. As FIG. 5 shows, even without the addition of NaOAc, a dramatic increase in viscosity is noted for the polymer product. Further discussion of the remarkable viscosity values is included later in the present disclosure.

[0106] Acid catalysts such as p-TSA or sulfuric acid may work but may also degrade the polymer. The tin(II) catalysts, Sn(II) acetate and Sn(II) octanoate, are either poorly soluble in DMSO or cause gelation of the polymer in DMSO. The reaction time at 80°C and subsequent cool down time before precipitation of the polymer product also affect the viscosity of the modified Selvol as shown in FIG. 6. FIG. 6 shows the effect of cook time at temperature and cool down time vs. product viscosity, reaction conditions: 5 wt% Selvol in DMSO; 5 mol% FAME hydrophobe in t-BuOH (16 wt % in reaction); 80°C; varying cook time and cool down. Again, the reaction conditions were identical except for the time at which the polymer product was precipitated into a non-solvent. The points at 7 hour cook time but different cool time before precipitation show that delaying the precipitation seems to modestly affect the viscosity.

[0107] Modification with hydrophobes derived from seed oil and seed oil FAMES: Hydrophobe effect on Viscosity.

[0108] Initial Selvol modification reactions were done using canola oil “as-is” (supermarket, food quality), without converting to the FAME derivative. Generally, it appears that the seed oils are less soluble than their FAME derivatives, and possibly more difficult to reproduce reaction results. There may be components in the seed oil that are absent after conversion to FAME. In the transesterification of a seed oil, glycerin is a by-product which cannot be removed conveniently during the reaction. The FAMEs, on the other hand, produce methanol as a by-product which is easily evaporated out of the reaction, thus helping to shift the reaction equilibrium toward desired product. When the FAME derivatives were eventually synthesized, they became the source of the hydrophobe for subsequent reactions.

[0109] Despite these differences, it was found that the products formed from hydrophobic modification of Selvol 125 using canola oil had remarkable viscosity increases, presumably due to an associative thickening effect. FIG. 7 shows the viscosity build begins around 1.5 wt% in water and increases exponentially beyond that point.

[0110] TABLE 2 below summarizes a few examples, showing some initial canola oil Brookfield viscosity results (Measurement: SC4-31 spindle, 0.1-2.0 rpm. ReactionConditions: 5 wt% Selvol in DMSO; various mol% seed oil in t-BuOH 16 wt % in reaction; 75-80°C; 6 hours; cooldown 2 hours). The loading levels needed to obtain a large viscosity effect are high, and do not represent what is actually incorporated into the polymer. The suggestion of rheopectic behavior is discussed later in the present disclosure; as TABLE 2 indicates, some indication of shear thickening or thickening upon standing was indicated in some of the products. In a few cases, the low shear (Brookfield) viscosity didn’t appear to settle, but would drift upward over time. However, the same samples, when subjected to a varying, high shear force, displayed more typical thixotropic or shear thinning behavior (see FIGS. 8A, 8B). The modified Selvol 125 is non-Newtonian at 4 wt% in water, compared to the unmodified Selvol 125.TABLE 2[OHl] FIGS. 8A and 8B show high shear viscosity profiles, with FIG. 8A showing Selvol 125, and 8B canola modified Selvol 125, 4 wt% in water at ambient temperature. Selvol 125 appears Newtonian, and modified polymer shear thins (thixotropic), at least under high shear. Arrows mark the approximate location of Brookfield shear rate.

[0112] A summary of reactions using canola oil FAME as the hydrophobe source are reported in FIGS. 9 - 11 and TABLE 3 further below.

[0113] FIG. 9 shows the smooth variation in viscosity with loading levels of canola oil FAME, more specifically, viscosity of Selvol 125 modified with canola oil FAME loaded at different mole ratios (Mol % are based on loading, not NMR analysis of product. Viscosity conditions: 4 wt% in water, 20°C, SC4-18 spindle, 3.0-60.0 rpm. Reaction conditions: 5 wt% polymer in DMSO; hydrophobe added in t-BuOH (17 wt % in reaction); 5-6 hour reaction time, 75-80o C. See Hl NMR data in TABLE 6).

[0114] The viscosities, though impressive, are lower than observed in other FAME reactions primarily because this series was run with a shorter reaction time and a little lower average reaction temperature. As discussed later, the loading levels do not represent the actual incorporation level in the polymer. Using the highest viscosity polymers from FIG. 9 as an example, FIG. 10 shows the expected, inverse relationship between viscosity and temperature. FIG. 10 is the viscosity of Selvol 125 modified with 5 mol% loading canola oil FAME vs. temperature, in other words the 5 mol% sample shown in the plot in FIG. 9 (Viscosity conditions: 4 wt% in water, 20°C, SC4-18 spindle, 3.0-10.0 rpm). FIG. 11 shows purified hydrophobes used as feedstocks in Selvol modification. Note in the molecular structures the relative chain extension due to cis double bond content.

[0115] TABLE 3 shows the effect of hydrophobe microstructure on viscosity.TABLE 3Specifically, purified FAMES were purchased that represent most of the composition of canola oil triglyceride. The cis double bonds increase in number from 0 to 3 as shown in TABLE 3 and FIG. 11. These 4 FAMES were reacted with Selvol 125 in the same reaction conditions, producing an associative thickening effect in the product that decreased withdouble bond number. One may speculate that this is due to the effective length of the side chain (and ability to undergo conformational isomerism) due to the presence of cis double bonds. The stearate modified polymer (no double bonds) was insoluble, instead forming a water-swollen, polymer rich phase as shown in the photograph of FIG. 11. Another observation is the color variation of the in-progress reactions with number of double bonds. The yellow coloration in unpurified FAMES or the seed oil itself is likely due to other components as well but obviously the amount of unsaturation plays a role in the color and the possibility that reactions other than transesterification are occurring that involve participation by the double bonds. It is interesting to note that the viscosities for these polymers (TABLE 3) are substantially lower using reaction conditions similar if not identical to reactions producing far higher viscosities using unpurified canola oil FAME. It is hypothesized that there may be a component in the oil or in its FAME derivative that catalyze, promote, or otherwise react to produce ultra-high viscosity products.

[0116] A comparison of canola oil FAME to coconut oil FAME and castor oil FAME is presented. Referring to TABLES 4A (canola oil), 4B (coconut oil), and 4C (castor oil), coconut oil is primarily saturated fatty acids with C8-C16 hydrophobes, most of it in the form of C12. Castor oil is primarily C18 chains with a large ricinoleic acid component, rendering it far more soluble in DMSO, presumably due to the presence of the hydroxyl group. As such, t-BuOH was not used as a co-solvent in reactions involving castor oil FAME. As mentioned previously, canola oil is primarily Cl 8 with an abundance of unsaturation. Notwithstanding solubility differences that arise when comparing saturated to unsaturated hydrocarbons, it is expected that shorter hydrophobes from coconut oil FAME will yield polymer viscosities lower than those from canola oil FAME, all other reaction conditions being similar.TABLE 4ATABLE 4BTABLE 4C

[0117] As TABLE 5 below shows, this is indeed the case. In this particular example, the polymer derived from canola oil FAME was so viscous it seemed to either “gel” or possibly phase separate but it was pourable (hence, not a true gel). The coconut oil FAME modified polymer was very white, the reaction essentially colorless which is a feature of reactions that do not have hydrophobes with a high degree of unsaturation (compare to stearate hydrophobe reaction illustrated in FIG. 8).TABLE 5

[0118] Properties of hydrophobically modified Selvol 125.

[0119] Viscosity, DSC, and Spectroscopy.

[0120] FIG. 12 illustrates an interesting phenomenon that was previously noted for Selvol 125 modified with canola oil. FIG. 12 shows viscosity drift vs. time under constant, low shear conditions (Spindle: SC4-34, 0.3 rpm). The viscosity drifted upward with time.

[0121] In other words, 4 wt% solution viscosity measurements were used to track reaction progress and to indicate any changes in Selvol 125 molecular structure. In summary, it can be concluded that the reaction modified the structure of Selvol 125, that it is most likely a transesterification reaction, and that low loadings of hydrophobe from FAME or seed oil sources produce an impressive associative thickening effect in water solutions, provided the polymer will substantially or completely dissolve without phase separation.

[0122] FIG. 13A shows the DSC thermogram for Selvol 125 substrate, and FIG. 13B shows stearate modified Selvol 125. The top line in each thermogram represents the 1stcooling, and then bottom line is the 2ndheating. The DSC thermogram for the hydrophobically modified polymers generally are not remarkably different than the Selvol 125 substrate. The hydrophobe loading is not detected, most likely because the melting transition for unsaturated,Cl 8 hydrophobes are around -50°C and the melting point of the polymer is generally within a few degrees of the Selvol 125 substrate. The stearate modified polymer, however does show a hydrophobe melting point. Since the saturated stearate Cl 8 chain melts around 38-39°C, its melting transition was discernable in the Selvol 125 modified polymer as shown in FIG. 13B. The melting temperature for the polymer is about 10°C higher than Selvol 125 at about 220°C, indicating that the hydrophobe does not interfere with crystalline domain formation from PVOH chains and the formation of a eutectic mixture of the two components does not occur.

[0123] A 10°C spread in Tm, using routine analysis parameters, is likely normal over various lots of the same PVOH, for example, in Finch, C.A. (ed) “Polyvinyl alcohol Properties and Applications,” John Wiley & Sons Ltd. 1973, reports the Tm of 99% hydrolyzed PVOH at 230°C. The Tg is lower than 85°C, the value reported in Finch for 99% hydrolyzed PVOH, but is modestly higher than the thermogram measured for Selvol 125 substrate. A shift to higher Tg value by a bulky side chain is a generally expected result, but many instances are known where the opposite occurs, ostensibly due to an equivalent plasticizer effect on the free volume of the polymer chains.

[0124] FIG. 14 shows a typical FTIR spectrum of hydrophobically modified Selvol 125. The sharp peak at 2850 cm-1 is indicative of terminal CH3 and band at 1740-1730 cm-1 is indicative of ester carbonyl attachment to Selvol 125 backbone. The FTIR spectrum in FIG. 14 is typical of what was seen in nearly all of the hydrophobe modified PVOH polymers. The incorporation levels are low but a good spectrum will indicate the presence of both the ester attachment to the Selvol 125 backbone and the terminal methyl group of the hydrophobe. The FTIR data is used qualitatively to indicate the presence or absence of functional groups.

[0125] As discussed and shown with reference to FIG. 9 previously, it is evident that loading levels of the hydrophobe effects the properties (e.g., viscosity) of the PVOH polymer product. However, TABLE 6 below shows the results of quantitative Hl NMR analysis of the same samples, canola oil FAME incorporation onto Selvol 125 (Sample 215-89 was likely contaminated with unreacted FAME, the anomaly indicated by the circle). These data indicate that the incorporation levels onto the Selvol 125 are similar; there is no trend. This result implies that the distribution on the Selvol 125 polymer chain varies with loading level (and thus a change in the way the hydrophobes may associate), perhaps indicating that molecular- level dissolution of the FAME in DMSO / t-BuOH reaction matrix is not occurring. But it is also known that the microstructure of the hydrophobe, i.e., degree of unsaturation, affects the viscosity (see TABLES 3, 5 and FIG. 11) so their distribution on the polymer chain may vary with loading levels due to steric effects.TABLE 6

[0126] The Hl NMR spectra were chosen for quantitative analysis because the signal of the terminal CH3 group of the hydrophobe is distinct and not overlapped with other proton signals. Its signal area is compared to the signal of the -CH- group in the PVOH backbone, set to an area = 1 proton. An example spectrum is shown in FIG. 15, with the top showing Hl NMR of canola oil FAME in CDCh, and the bottom showing an example of Hl NMR spectrum of FAME modified Selvol 125. Another curious feature of the spectrum is the ratio of the signal due to the alkene attached protons to the terminal CH3 signal. In FAME, the ratio is near 1. In the modified polymer, it is less than 1, suggesting something is happening to the double bonds during the reaction.

[0127] Modification with (S)-methyl lactate in DMSO.

[0128] To date, only a few attempts have been made to modify Selvol 125 with methyl lactate and methyl glutamate, using a DMSO process. In this section, data from one specific attempt is highlighted to demonstrate proof of concept (Sample is 215-115-lMeL). Hence, FIGS. 16 - 18 all represent the same sample. For reaction conditions, refer to the above disclosure regarding reaction examples.

[0129] Qualitatively, the lactate modified polymer displays a remarkable, rapid rate of dissolution in water and in fact, the 4 wt % solution used for routine viscosity measurements was prepared by stirring at room temperature, no applied heat. FIG. 16 shows the DSC thermogram of lactate modified Selvol 125, with top line representing 1stcooling, and bottom line representing 2ndheating. The DSC thermogram suggests the crystallinity of the PVOH has been disrupted, showing a broad Tm with a maximum at 155°C, well below the Tm of Selvol 125. Further, the Tg is modestly higher than the Selvol 125 thermogram example reported in FIG. 13 A, which is generally the expected result with the introduction of a largergroup on a polymer chain. But as before, the Tg is significantly lower than the Finch reported value for 99% hydrolyzed PVOH. The fact that the melting temperature is severely altered probably supports the idea that the lactate group prevents packing together of chains. Further, a DSC analysis of mixed, unreacted feedstocks indicates that the reaction did occur.

[0130] The spectroscopic analyses shown FIGS. 17 and 18 indicate the expected reaction. The FTIR has a strong ester band and the C13 NMR indicates the absence of the methyl ester CH3 but the presence of all other lactate signals in the polymer. In the C13 spectrum, the origin of the signals marked with an arrow are likely residual sodium acetate used in high loading as a catalyst in the reaction. The possibility of pendent dimers or short chain polylactic acid chains was considered but spectral evidence is lacking. The existence of short polylactic acid chains could explain the dramatic change in Tm but maybe a single, pendent lactate group suffices. Using the peak signal at about 21 ppm, quantitative Cl 3 NMR indicates a loading of about 5-5.5 mol%.

[0131] Modification with y-methyl-L-glutamate in DMSO.

[0132] FIGS. 19 - 21 show evidence of the reaction of glutamate with Selvol 125 in DMSO solvent. In FIG. 19, an example of the classic ninhydrin reaction with the glutamate modified polymer is shown. The reaction is designed to detect the presence of free a-amino acid functionality in a molecule or as a component of a mixture. The blue-purple complex indicates a positive test.

[0133] FTIR spectra shown in FIG. 20A of the carbonyl absorption region suggests a low loading of glutamate via an ester attachment but does feature expected absorptions a for pendent glutamate moiety, namely carboxylate and amino groups. However, there is some overlapping interference from the Selvol 125 backbone that makes the interpretation difficult. FIG. 20B is the C13 NMR spectrum of the same compound. The glutamate loading on the polymer is low and signal due to the glutamate graft is difficult to detect. It does appear that the methyl group of the methyl ester is absent and the ester carbonyl is shifted in the modified polymer, both indicative of the structures presented in FIGS. 4 A and 4C.

[0134] As shown in FIG. 21, DSC traces of glutamate modified Selvol 125 (top line is first cooling, bottom line is second heating), the melting point of the glutamate modified Selvol 125 is shifted significantly lower and Tg significantly higher, though a re-precipitation and re-analysis moved the melting point nearer to typical PVOH values. This seems to suggest that perhaps the product is a mixture of unreacted feedstocks. However, a DSC analysis of mixed, unreacted glutamate and Selvol 125 did not suggest this was the case.

[0135] PVOH vinyl amine copolymer - Ultiloc 5003 modifications.

[0136] Modification with hydrophobe derived from seed oil and seed oil FAMES in DMSO.

[0137] The basic process for modification of Selvol 125 is similar to hydrophobically modified Ultiloc 5003. Namely, t-BuOH is used as a co-solvent for the hydrophobe but the NaOAc catalyst is not used. We count on the nucleophilic quality of the amine group in Ultiloc to make amide attachments to the same seed oils or FAMEs used as hydrophobic modifiers of Selvol 125. As before, water-based processes are difficult for the same reasons stated previously so in this section most of the products described were produced in the DMSO / t- BuOH process.

[0138] TABLE 7 provides a summary of some of the products produced using Ultiloc 5003 substrate and canola oil or castor oil based hydrophobes (Ultiloc 5003 viscosity of 6.00 cP at pH 10 and 8.64 cP at pH 7.5).TABLE 7Note that seed oils were also used to demonstrate the possibility of using “as-is” seed oil feedstocks directly. Also note that there is a significant, pH dependent solubility and viscosity difference for the samples due to the unreacted free amine groups in the modified products.

[0139] Generally, loading hydrophobes above 1 mol % creates water solubility limitations. For example, products from 1 mol% and 10 mol% loading are not water soluble. Adjusting the pH to near neutral makes the 1 mol% sample water soluble, presumably due to cationic charge on the free amine groups. As shown in FIG. 22, the sample having 1 mol% loading ofhydrophobe from castor oil FAME (shown on the left) foams significantly during preparation of a 4 wt% water solution. A pH adjustment does not render the 10 mol% sample soluble (shown on the right), presumably because there are not enough free amine groups remaining to impact solubility. However, it will dissolve by heating several hours at 80°C in DMSO and remain soluble at room temperature.

[0140] It appears that FAMEs are more efficient modifiers than the parent seed oil, as evidenced by the solubility and viscosity differences noted for each in TABLE 7. Specifically, at 1 mol% loading, the products from the seed oil based modifications were water soluble at a pH ~10 (meaning no pH adjustment was necessary to dissolve) and had significant viscosity improvements compared to Ultiloc 5003. But compare to the second row and last row entries in TABLE 9 further below. These were prepared from the FAMEs; their water solubility was achieved only by lowering the pH and their viscosities, compared to Ultiloc 5003, are 1-3 orders of magnitude higher. As noted for Selvol 125, castor oil FAME hydrophobes have a smaller effect on viscosity than canola oil FAME hydrophobes.

[0141] Modification with chiral groups derived from (S)-methyl lactate and (S)-5-methyl glutamate in water.

[0142] (S)-methyl lactate and (S)-5-methyl glutamate feedstocks are water soluble. Since the amine group in Ultiloc 5003 can out-compete hydroxyl group or water in nucleophilic acyl substitution reactions, water was used as the reaction solvent to prepare Ultiloc 5003 modified polymers. The reactions appeared to be quantitative. Hence, the polymer products may be isolated merely by evaporating the water from the reaction, leaving a polymer film behind that is the modified Ultiloc 5003. These polymers tend to adhere strongly to substrates like aluminum and glass so the evaporation of water from the polymer was generally done in a polypropylene (or Teflon if available) pan.

[0143] FIG. 23 shows a quantitative C13 NMR spectral comparison of the methyl ester feedstocks (see FIG. 3C) and the modified Ultiloc 5003 polymers. It clearly indicates an amidation reaction occurred and the signal integration indicates about 10 mol% incorporation, the targeted quantity.

[0144] As shown in FIG. 24, DSC thermograms of lactate (MeL), and glutamate (GLU) modified Ultiloc 5003, Ultiloc 5003 (far left graph) showed no thermal events in its DSC thermogram, at least under the typical run conditions used for PVOH analysis. Modification by lactate (middle graph) or glutamate (far right graph) introduced a discernable glass transition at about 100°C. These Tg values are significantly higher than the lactate modified Selvol 125 shown in FIG. 16.

[0145] Due to the amine groups in the polymer, water solutions of Ultiloc 5003 are very basic, typically having pH values in excess of 10 for solutions 4 wt% or higher. As shown in FIG. 25 A, the addition of MeGLU to the polymer solution rapidly lowers the pH to around 9- 10, ultimately changing to neutral as the Ultiloc 5003 and MeGLU react. Clearly, the formation of the amide from the amine will lower the pH and amino acid group itself will be near neutral in the absence of other acidic or basic components. Creating a pH profile like FIG. 25A for this reaction (or the lactate modification) was a simple way to follow reaction progress and demonstrate the reaction was occurring.

[0146] One of the interesting and perhaps useful features of the structure produced by modifying Ultiloc 5003 with glutamate is the presence of zwitterions on the polymer backbone. The ionic charge of the amino acid can be changed by adjusting pH. In FIG. 25B, a titration curve of a water solution of glutamate modified Ultiloc 5003 is shown. Like typical amino acids, we were expecting to find inflection points in the curve that represent changes in the charge distribution. Above pH ~ 9.8, the pendent amino acid is neutral on the amine group and (-) on the carboxylic acid. At pH ~ 6.2 , the group is neutral (zwitterionic), and below pH- 2.4, the pendent amino acid is (+) on the amine group and neutral on the carboxylic acid.

[0147] Industrial Applications

[0148] There are numerous applications where the modified polymers may be employed. TABLE 8 provides a summary of potential applications for modified Selvol or Ultiloc 5003, where SO = seed oil, AA = amino acid, L = lactate, S = Selvol, and U = Ultiloc 5003.TABLE 8

[0149] TABLE 9 shows a Film Solubility Test of lactate modified PVOH at room temperature (samples drawn down from 10 wt% solutions, oven dried 30 minutes at 80°C, stand several hours at 50% relative humidity). Rapid, room temperature solubility in water was observed for this sample so the Film Solubility Test described previously was used to evaluate films of the modified polymer. As expected, the unmodified polymer shows no propensity to disintegrate or dissolve in ambient temperature water (20-22°C). On the other hand, the lactate modified polymer shows a marked improvement in water solubility and other, qualitative observations bear this out. In short, these polymers dissolve with stirring at room temperature and quite rapidly with heating of the solution. There is a remarkable difference in water solubility due to the pendant lactate group, rendering films of the polymer dissolved or disintegrated in mere minutes at room temperature. Selvol 125 virtually does not disintegrate or dissolve under these conditions. The lactate modified polymer broke through in a few seconds and disintegrated in a couple of minutes, and dissolves in under 10 minutes, conservatively.TABLE 9

[0150] TABLE 10 shows the results of some oxygen transmission rate (OTR) experiments, for various Selvol or Ultiloc 5003 modified polymers at 0, 50, and 75% relative humidity (units are cc / m2-day). Enhanced oxygen barrier was noted for glutamate and hydrophobically modified PVOH, even up to 75 % RH. The lactate modified polymers, probably due to their improved water compatibility, were poor oxygen barriers, especially at high humidity.TABLE 10

[0151] FIG. 26 shows 0.2wt% surface tension measurements for Selvol 125 modified with seed oil hydrophobes. The surface tension of these solutions is greater than that of the unmodified PVOH but lower than pure water itself.

[0152] FIG. 27 shows the results of oil resistance when paper is coated with hydrophobically modified (canola oil FAME) Selvol 107. The dark rings are oil penetration at pinholes or coating imperfections. The picture at top left shows no oil seepage into the paper. It was surprising to discover an excellent oil resistance or barrier to penetration of the paper when these polymers were used to coat the paper.

[0153] FIG. 28 shows methanol compatibility of Selvol 523 after modification with methyl lactate. On the left is the lactate modified polymer, and on the right is the unmodified Selvol 523. Solubility enhancement was noted for lactate modified Selvol 523 when the PVOH substrate had a low degree of hydrolysis (85-88%). The modified polymer showed solubility and swellability in methanol at ambient temperature conditions.

[0154] Accordingly in view of the synthesis methods and modified PVOH chemistries and properties produced as described in the present disclosure, using the methyl ester derivatives of triglycerides, lactic acid, glutamic acid, and aspartic acid (all commercially available biomass), it was demonstrated that transesterification or amidation reactions with PVOH homopolymers or amine containing PVOH copolymers were possible. Modifications on PVOH homopolymers were successful using a DMSO or DMSO:t-BuOH solvent matrix. Modifications of amine containing PVOH copolymers were successful in DMSO or a water matrix.

[0155] Significant property changes were noted in the modified polymers, including but not limited to remarkable viscosity increases in hydrophobically modified polymers, solubility improvements in lactate modified polymers, and increases in Tg for lactate or glutamate modified polymers. The lactate and glutamate modified polymers also possessed chirality that is absent in the parent substrate polymer and that may be exploitable in certain application spaces.

[0156] Further, it is believed that the compositions produced by the processes of the present disclosure are novel when derived from plant based triglycerides, for example, which structurally differentiates them.

[0157] Although only a few example embodiments have been described in detail above, those skilled in the art will readily appreciate that many modifications are possible in the example embodiments without materially departing from this invention. Accordingly, all such modifications are intended to be included within the scope of this disclosure as defined in the following claims.

Claims

CLAIMS1. A modified PVOH polymer comprising a hydrophobic modification with a triglyceride seed oil.

2. The modified PVOH polymer of claim 1, wherein the triglyceride seed oil is one or more selected from the group consisting of canola oil, castor oil, coconut oil, soybean oil, and methyl ester (FAME) derivatives of seed oil.

3. The modified PVOH polymer of claim 2, wherein the PVOH polymer comprises an amine.

4. The modified PVOH polymer of claim 3, wherein the PVOH polymer is a copolymer of vinyl amine.

5. A modified PVOH polymer comprising a hydrophilic modification with a lactate or an amino acid.

6. The modified PVOH polymer of claim 5, wherein the amino acid comprises an ester functional reactive group.

7. The modified PVOH polymer of claim 5, wherein the lactate or the amino acid comprises one or more selected from the group consisting of (S)-methyl lactate; L-lactide; (S)-glutamic acid- 5-methyl ester; (S)-glutamic acid-l-methyl ester; (S)-aspartic acid-4-methyl ester; and (S)-aspartic acid- 1 -methyl ester.

8. The modified PVOH polymer of claim 5, wherein the PVOH polymer comprises an amine functional group.

9. The modified PVOH polymer of claim 8, wherein the PVOH polymer is a copolymer of vinyl amine.

10. The modified PVOH polymer of claim 5, wherein the lactate or the amino acid is grafted onto the PVOH backbone through ester or amide linkages.

11. A process for producing the modified PVOH polymer of claim 5, comprising a one-step reaction of PVOH with methyl ester derivatives of the amino acid or lactic acid in water.

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