Progress 09/01/13 to 04/30/14
Outputs
Target Audience: The overall objective of our proposal was to prepare polyols suitable for polyurethanes coatings from protein biomass. This program involves breaking the protein chain to amino acids, protecting the carboxylic acids and converting the amines to hydroxyl terminated pre-polyurethanes. Key achievements to date include successful cleavage of the proteins by trans-amidation reaction with ethanol amine and preparation of the desired hydroxyl terminated pre-polyurethane intermediates from these intermediates. The process is being scaled-up to produce large volumes of these polyols for further evaluation by our industrial partners. Positive responses of our initial samples were received from Foam Supplies, LLC and the Sherwin-Williams company. Key advantages these polyol intermediates and PU products are related to their significantly lower cost compared with similar petroleum-based, relatively simple process that does not require special equipment or expensive reagents and readily available raw materials Changes/Problems: The polyols developed in this activity appear to be suitable for the production of rigid polyurethane foams in addition to polyurethane coatings What opportunities for training and professional development has the project provided? Two graduate students and a Post-docturate fellow from the Chemical Engineering and Materials Science Depatment at Michigan State University were trained in this technology. How have the results been disseminated to communities of interest? A summary of the initial evaluation of these polyols by Sherwin-Williams Company was written by Brian T. Makowski, Ph.D. and is given below: OVERVIEW: The MSU Soy-CL-OH polyol was evaluated in 2K solvent based systems using Desmodur® N3300A as the isocyanate at an NCO:OH ratio of 1.05. To enhance film formation, the soy polyol was combined in different ratios with a clear all acrylic resin (Sherwin-Williams confidential), which is a fast drying, solvent-borne system. The polyol was first dissolved in NMP to make a solution containing 57% solids. The solution was blended with the SW acrylic resin at 25, 50 and 75% by weight. The blends along with the native Soy-CL-OH/NMP solution were drawn down on cold rolled steel panels and tested for gloss, hardness, adhesion, flexibility and chemical resistance. Goal: The NISO polyol provided by MSU to SW was recently screened for possible application in 1K and 2K polyurethane systems. The following procedures were used: Use in a 1K polyurethane dispersion (PUD): A polyurethane prepolymer was made with the NISO polyol, DMPA (Perstorp), and IPDI (Bayer) at an NCO:OH ratio of 1.28. The prepolymer was dispersed into water at ~80 °C. The prepolymer had acceptable viscosity, but it swelled considerably once dispersed in water, indicating high water sensitivity. Use in a 2K polyurethane: It was found that the polyol is soluble in water. A 35% solids solution was made for use as a polyol component for 2K application. A water-dispersible isocyanate component supplied by Bayer (Bayhydur 302, NCO:OH ratio 1.5) was added to the polyol/water solution immediately prior to application to a Leneta opacity chart. The coating was still tacky after two weeks. This is likely due to the high water sensitivity of the polyol. MATERIALS AND METHODS: N-methylpyrrolidone (Sigma-Aldrich, ≥ 99.0%), Desmodur® n3300a (Bayer Material Science) were used as received. Test methods: ASTM D 3633 (Pencil Hardness), ASTM D 523 (Gloss), ASTM D 3359 (Adhesion), ASTM D4366-95 Hardness of Organic Coatings by Pendulum Damping Tests, ASTM D 522 (Conical Mandrel), ASTM D 1308 (Chemical Resistance). Stains and chemical spots were covered with a watchglass for the duration of exposure and allowed one-hour recovery prior to evaluation. The following scale was used to rate the stains and chemicals: Table 4: Chemical Resistance Ratings: 5: Spot undetectable. 4: Spot detectable at some angles. Slight ring from reagent or watchglass. 3: Spot detectable at all angles. Ring from reagent or watchglass. 2: Slight attack (some surface damage - rough, soft, complete whitening, couple blisters). 1: Heavy attack (puffy, severe blisters, rust, etc.) 0: Substrate visible. Table 5: Properties of different blends of Soy-CL-OH and the SW acrylic resin. Soy-CL-OH/NMP solution: Weight (g) 40 30 20 10 0 SW Acrylic: Weight (g) 0 10 20 30 40 Pencil Hardness: 6B 2H 2H 2H 2H 20 Deg Gloss: Degrees 2.3 10.9 2.9 10.9 10.9 60 Deg Gloss: Degrees 9.1 44.5 9.3 37.3 37.3 Konig Pendulum: 6 19 51 103 162 Water Chem. Res.: 0 1 1 0 5 10% HCL Chem Res: 1 1 2 1 4 10% Acetic Acid: 1 1 2 1 3 10% NaOH: 2 1 3 2 4 10% H2SO4: 1 1 3 3 5 Ethanol: 1 1 3 4 3 Toluene: 4 4 4 4 4 MEK: 3 3 3 4 4 Xylene: 4 3 4 4 4 Chemical Resistance Total: 1.89 1.78 2.78 2.56 4.00 Cross Hatch Adhesion 5 3 5 5 0 Mandrel Bend: Pass Pass Pass Failed CONCLUSIONS: Increasing the ratio of Soy-CL-OH to SW acrylic resin in the blends improved the adhesion to cold rolled steel, and the film flexibility (see Table 5). This trend was accompanied by a decrease in chemical resistance and hardness. The water resistance was particularly poor even for a blend containing only 25% Soy-CL-OH. As found in the previous report (sent on Oct 1st, 2013 and also attached in the appendix as a reference), the neat Soy-CL-OH could be dissolved completely in water at least up to 35% solids. ADDITIONAL OBSERVATIONS: The solubility of the Soy-CL-OH was poor in most solvents, including butanol, butyl cellosolve, acetone, butyl carbitol, and xylene. The polyol dissolves in NMP, but needs a substantial amount (~50% solids). The best solvent for Soy-CL-OH is water. RECOMMENDATION: For high performance applications, it is recommended that the water sensitivity of the polyol backbone be decreased in future samples. A summary of the initial evaluation of these polyols by Foam Supplies Inc. was written by Mark Schulte - Director of PU Chemistry, and is given below: The initial work we have done with the sample has been mostly positive in a spray foam. The negatives are %closed cell, viscosity, acid# and purity. All of these should be easily addressed. We would like the acid # below 3 preferably below 2. If this process would add too much cost we would try to formulate around it. We know various diluents that could be used to reduce the viscosity whose effect on physical properties could be mediated by other formula changes. Purity is in reference to visible solids floating in the sample. Filtering shouldn't be a problem. % closed cell hopefully is just a matter of surfactant choice. If this molecule is similar to the ones in Elodies paper, I don't see how it could be adding to the cell opening. Past experience with an ethoxylated sucrose or ethoxylated glycerine at a certain equivalent weight tends to open cells but I don't know why this ester would. We would need to do more work to see if we can get higher closed cell content. So, my conclusion would be it is very worthwhile looking at more of this polyol. Because of manpower issues, the quickest way to get testing done would be if you had people who could do the bench work under our direction. That would mean having the mixing capabilities comparable to ours. I don't know if Elodie got that far or not. I would be willing to have one of your candidates spend a day or 2 here for training on technique if that would be helpful. If you cannot provide the man power it may take longer than you can wait for us to get results. What do you plan to do during the next reporting period to accomplish the goals?
Nothing Reported
Impacts
What was accomplished under these goals?
The overall process is based on cleavage of the amide linkages of the proteins with ethanol amine to yield amido-amine intermediates. The process does not follow the traditional hydrolysis of proteins to individual amino acids which then require protecting the carboxylic acid groups. Instead, the intermediates that are obtained are a mixture of amines terminated amides and hydroxyl-amine terminated amides. These different intermediates are obtained since ethanol amine can react with the carboxylic groups of the amino acids via two different routes; 1. diamine terminated products are obtained when the hydroxyl group of ethanol amine reacts with the carboxylic group of the amino acid, and 2. hydroxyl-amine terminated products are obtained when the amine group of ethanol amine reacts with the carboxylic groups of the amino acids. Task 1: Protein hydrolysis – completed successfully In a typical experiment, we used defatted soy flour (white flakes) as a protein biomass. This protein is simply a fine powder that contains about 50% protein. The flour was washed several times in 60% aqueous alcohol solution to remove soluble carbohydrate, lectins, trypsin inhibitors, glycinin, B-conglycinin, saponins and any other soluble oligosaccharides. The high concentration of alcohol in the wash solution caused the protein to denature, which further decreased its solubility and thus improved the overall yield. Initially, the washed proteins sample was then hydrolyzed under acidic conditions (2N HCl) and then neutralized with NaOH. The insoluble carbohydrates precipitate was then removed by filtration. Water was then removed from the clear solution containing the amino acids to yield a mixture of amino acids. The process was improved by using ethanol amine as a trans-amidation reagent whereby it eliminates the need to distill large quantities of waste water and disposal of the NaCl salt that was obtained from the neutralization step. Furthermore, the trans-amidation reaction was completed in a few hours instead of 12 hours that was required for the hydrolysis process. Task 2: Amination – completed successfully In the early stages of the project, the carboxylic groups of the amino acids that were obtained by hydrolysis were “protected” by the reaction with ethylene diamine that produced the amido-amine derivative. This reaction was achieved when the amino acids from Task 1 were allowed to react with ethylene diamine using dialkyltin dicarboxylate as the condensation catalyst. A large excess of ethylene diamine was required in order to minimize a possible dimerization (or oligomerization) reaction where both amines are reacted with carboxylic acids. The acid value and the amine value of the amination product mixture were obtained to ensure that all of the carboxylic acids were reacted such that they will not interfere in the formation of the urethane linkages in subsequent reactions (Table 2). The outcome of this task was greatly improved by avoiding the hydrolysis process and, instead, using the trans-amidation reaction with ethanol amine. The intermediate products that were obtained were diamine terminated esters when the hydroxyl group of ethanol amine reacted with the carboxylic group of the amino acid and hydroxyl-amide termined amides when the amine group of ethanol amine reacted with the carboxylic acid of the amino acids. Task 3: Pre-polymer preparation– completed successfull The diamine and hydroxyl-amine derivatives from Task 2 were then reacted with ethylene carbonate to yield the desired polyols. The reaction of amines with ethylene carbonate is well known and proceeded smoothly even with no catalyst or a solvent at 40°C to yield the desired urethanes (carbamate). The product mixture was analyzed by FTIR, hydroxyl value (ASTM D4274) and acid number (ASTM D4662) and the structure of the pre-polyurethane derived from the Glycine model compound was confirmed by NMR. The FTIR of the urethane intermediates that were obtained from the reaction of the amido-amine derivative of Glycine with ethylene carbonate model compound further confirmed the success of this reaction step and clearly showed the appearance of the carbamate (urethane) peak at 1690 cm-1 in addition to the amide peak at 1654 cm-1. The FTIR spectra clearly showed the appearance of a peak at 1570 cm-1 and 1660 cm-1, corresponding to the conversion of the amine to amide in the aminated intermediate. After reaction with ethylene carbonate a new peak appears at 1700 cm-1, corresponding to C=O groups in the new urethane functional group. Scale-up of the soy meal-based polyol: A 10 Kg batch of soy meal-based was used to explore the scale-up procedure to polyurethane. Since the meal is composed of 44% of proteins, 0.5% of fat, 7% of filter, 12% moisture and 36.5% of soluble and insoluble carbohydrates [[1]]. Thus, the maximum polyol yield would be 4.4 Kg. The flow chart presented in Figure 8 provides the general process that was used. Soymeal -----> washing -----> trans-amidation ----> carbonylation -----> Urethane Polyol Preliminary cost analysis was prepared based on the material balance. It indicates that the polyurethane pre-polymers from the soy meal can be produced for 0.88 $/lb. This cost estimate is favorable compared with current costs of polyols, MDI or TDI. This preliminary analysis is based on the relative concentration and functionality of the amino acids in the meal. For example, Arginine (ARG) content is 7.90% based on the total weight of amino acids. It requires 1 mole of ethylene diamine to protect the single carboxylic group and 3 moles of ethylene carbonate to produce the hydroxyl terminated tri-urethane. Thus, 100 lb. of soy protein require 77.72 lb. ethylene carbonate and 210.19 lb. ethylene carbonate. It follows that the material cost for this batch is ~ 0.88 $/lb. This is only a preliminary figure that does not include actual yield, processing costs, labor, overhead, etc.However, it is sufficiently low to justify a more in-depth analysis based on actual process.
Publications
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2014
Citation:
Green Route to Poly(amide-urethane)s from Plant Oil Dimer Acids D. Graiver*, E. Hablot, and R. Narayan Michigan State University, East Lansing, MI, USA
Session: IOP 4.0: Polymers and Additives
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