Source: Specialty Biopolymers Corporation submitted to
BIOLOGICAL POLYMER-BASED GREEN ADHESIVES FROM RENEWABLE RESOURCES
Sponsoring Institution
National Institute of Food and Agriculture
Project Status
TERMINATED
Funding Source
Reporting Frequency
Annual
Accession No.
0199766
Grant No.
2004-33610-14384
Project No.
MONK-2004-00017
Proposal No.
2004-00017
Multistate No.
(N/A)
Program Code
8.1
Project Start Date
May 15, 2004
Project End Date
Mar 31, 2005
Grant Year
2004
Project Director
Mittelman, M. W.
Recipient Organization
Specialty Biopolymers Corporation
(N/A)
Bozeman,MT 59718
Performing Department
(N/A)
Non Technical Summary
Specialty Biopolymers Corporation (SBC) is a Montana-based company that is developing microbial extracellular polymers (EPS) as environmentally friendly wood products adhesives. SBC will utilize bacterial EPS synthesis in the development of novel adhesives through biological processes, exploiting our knowledge of biological adhesion processes. Preliminary test results show that the adhesive shear strength of the SBC candidate EPS is 2,000 psi on maple at 50% RH, approximately equivalent to that of an industry standard wood adhesive. Existing wood adhesives are derived from synthetic, petroleum-based materials. These products often contain volatile organics (VOCs) and other toxic chemicals. As wood adhesives, bacterial exopolymers distinguish themselves from all other products through their synthesis using renewable agricultural products, the absence of VOCs and other toxic chemicals, and favorable costs of production. Replacement of VOC- and other toxic chemical-containing synthetic wood adhesives will: 1) reduce the need for cabinet makers and other wood crafters to construct and maintain expensive ventilation systems to protect workers from VOC vapor intoxication, 2) reduce worker exposure in manufacturing plants to toxic materials, 3) eliminate the generation of toxic waste products, 4) provide health benefits to consumers with chemical sensitivities, and 5) create a new market for agricultural feedstocks. SBC will utilize bacterial extracellular polymer synthesis in the development of novel adhesives through biological processes.
Animal Health Component
100%
Research Effort Categories
Basic
(N/A)
Applied
100%
Developmental
(N/A)
Classification

Knowledge Area (KA)Subject of Investigation (SOI)Field of Science (FOS)Percent
5110650202025%
5114010111075%
Goals / Objectives
Our vision is to utilize bacterial EPS synthesis in the development of novel adhesives through biological processes, exploiting our knowledge of biological adhesion processes. Several investigators, including the principals of Specialty Biopolymers, have investigated the physicochemical aspects of these interactions for a variety of substrata. Our objective is to determine whether the known adhesive properties of certain bacteria can be exploited commercially. Preliminary studies with EPS-I, a polysaccharide produced by an aerobic bacterium have demonstrated adhesion characteristics comparable with those associated with some commercially available wood adhesives. In Phase I, we plan to use EPS-I as a test compound for determining the overall feasibility of using EPS as a wood products adhesive. There are many variables that control adhesive performance and our Phase I objectives will establish those key factors before further development. Our Phase I objectives are: 1. Determine the key compositional effects on EPS-I adhesion. Obtain at least three EPS-I samples of varying grades or molecular weights from each of four different commercial sources and test for adhesive strength. The optimum adhesive strength will be correlated with EPS-I composition by analytical characterization of molecular weight, branching, sugar unit, and impurity analysis. 2. Determine the key effects of formulation additives, application variables, and use conditions such as temperature and humidity on adhesive strength. 3. Determine the feasibility of using EPS-I as adhesive in wood product laminates (plywood). 4. Develop a detailed process development and commercialization plan for Phase II research efforts.
Project Methods
Task 1. Determination of optimal EPS-I composition. Samples will be obtained from at least four EPS-I manufacturers/suppliers. Materials are produced in various molecular weight ranges and we will test a range of three values, low, medium, and high molecular weights (e.g., 100,000; 500,000; and 1,000,000 Daltons). Adhesive strength testing will employ ASTM D 905-94, Standard Test Method for Strength Properties of Adhesive Bonds in Shear by Compression Loading. Task 2. EPS-I formulation optimization. Preliminary results have shown that addition of small quantities of a surfactant, or wetting agent, significantly improved the adhesive strength of EPS-I. Most commercial adhesives incorporate additives to increase performance and reduce cost. For example, thickeners are added to control flow properties, plasticizers reduce the glass transition temperature (softening point) and increase toughness. Three concentration levels will be tested using selected, commonly used additive compounds. The adhesive preparation/gluing/curing operations will be performed as described in Task 1 (ASTM D 905-94). Task 3. Development of Application Methods and Use Parameters. The effects of cure time and temperature will be determined by testing adhesive strength at five time points over a two week period at three different temperatures, 20, 50 and 80 C and at a constant relative humidity. The effect of application thickness will be determined by controlling the pressure used to clamp the wood specimens after adhesive application. The bond thickness will be measured by difference between the thickness of the wood substrate pairs before and after glue application.We will determine the adhesive strength at different values of temperature and humidity and establish a useful range of use conditions for the EPS-I formulations. Such a test is described in ASTM D 4317, Standard Specification for Polyvinyl Acetate-Based Emulsion Adhesives. Task 4. Evaluation in plywood applications. We will perform a feasibility study of the utility of EPS-I-based adhesives using industry-recognized tests for laminate applications. Studies of composite applications will be considered for subsequent research. Currently used adhesives will be evaluated in side-by-side comparison tests. We will use the experiments described in Task 3 for testing of use conditions which employ the plywood shear testing method, ASTM 906, to also judge the feasibility of our adhesive in plywood applications. Task 5. Preparation of Final Report and Development of Process Development and Commercialization Plans. The results of the feasibility studies will be integrated into a commercialization plan to be implemented as part of a Phase II SBIR program. The key EPS-I compositions and formulations, application methods and use conditions, and wood products applications will be identified for larger scale testing. The commercialization program will include dissemination of adhesive samples to leading industries in the wood products industry. Where feasible, joint development or licensing arrangements will be devised to enable the large-scale production and packaging of the final adhesive formulation.

Progress 05/15/04 to 03/31/05

Outputs
Existing wood adhesives are derived from synthetic, petroleum-based materials. These products often contain volatile organics (VOCs) and other toxic chemicals. As wood adhesives, bacterial exopolymers distinguish themselves from all other products through their synthesis using renewable agricultural products, the absence of VOCs and other toxic chemicals, and favorable costs of production. Replacement of VOC-and other toxic chemical-containing synthetic wood adhesives will: 1) reduce the need for cabinet makers and other wood crafters to construct and maintain expensive ventilation systems to protect workers from VOC vapor intoxication, 2) reduce worker exposure in manufacturing plants to toxic materials, 3) eliminate the generation of toxic waste products, 4) provide health benefits to consumers with chemical sensitivities, and 5) create a new market for agricultural feedstocks. The Phase I SBIR project had 5 major goals: identification of optimal EPS composition, formulation optimization, development of application methods and use parameters, evaluation of plywood applicability, and improving moisture resistance. We have substantially met all of these goals, and developed a series of commercially viable EPS adhesives. Shear strengths associated with maple wood bonding applications have exceeded 3,000 psi (wood failure) for the SBC adhesive. In a study of the setting rate (shear strength vs. time) of the SBC adhesive, maximum shear strength at either 23 or 53 % relative humidity (RH) was reached at 2 days while half of maximum strength was reached at 2 h. Finally, we instituted a molecular modeling program to explore the mechanism of interaction between wood surfaces and extracellular polysaccharide adhesives of microbial origin. The goal of the modeling effort is to improve EPS adhesive performance by developing a more robust theoretical framework that can better describe the fundamental mechanisms by which EPS interacts with wood and other materials of interest. Specific objectives that were addressed in the modeling program at SBC included 1) predictions of which EPS adhesives interact most strongly with modeled wood surfaces, 2) describe the fundamental chemical mechanism(s) by which EPS adhesion to modeled wood surfaces takes place, and 3) determine the relationship between the type of EPS derivatization (e.g., acetylation, succinylation, etc.) and the theoretical water resistance of the adhesive bond. Overall, the performance of EPS-I meets many requirements of a wood adhesive but is lacking primarily in moisture resistance. In its present form, it may be suitable for interior, non-structural applications. Preliminary results with new, related compositions have shown the ability to improve moisture resistance by structural modification of the base polymer. Considering the compelling need for wood adhesives which are non-hazardous and based on renewable resources, continued research on improved EPS materials for this application is justified.

Impacts
For the first time, a microbially-produced extracellular polymer has been developed as a wood products adhesive. Many of the properties associated with this adhesive are similar to those of currently marketed products. The Specialty Biopolymers Corporation adhesive is effective, environmentally friendly, biodegradable, and produced from renewable resources. As such, this adhesive should serve as a prototype for future "green" adhesive products. We have had substantive discussions with a number of potential customers for our biologically-derived adhesives. The feedback from these discussions has been very positive, and has resulted in changes to the formulation chemistry to meet the specific requirements of particular applications. We have provided samples of various adhesive formulations to a number of small and large adhesive consumers. SBC has developed formal collaborations with two companies in the fine arts manufacturing business: both companies have very specialized applications for our adhesives, and have found the products to be far superior to products currently marketed for their manufacturing operations.

Publications

  • Haag, A.P., G.G. Geesey, and M.W. Mittelman. 2005. Bacterially derived wood adhesive. Int. J. Adhesion Adhesives (accepted 2/05).
  • Geesey, G.G., M.W. Mittelman, A.P. Haag, and H. Ridgway. 2005. Wood adhesive derived from bacterial extracellular polysaccharides. Abst. Ann. Meet. Adhesion Soc. Am., February 13-16, Mobile, AL