2007 Annual Meeting Technical Papers

DEMONSTRATION OF MILITARY COMPOSITES WITH LOW HAZARDOUS AIR POLLUTANT CONTENT
Dr. John J. LaScala, Army Research Laboratory
(Composites and Tooling Committee)
Liquid resins used for molding composite structures are a significant source of volatile organic compounds (VOC) and hazardous air pollutant (HAP) emissions.  One method of reducing styrene emissions from vinyl ester (VE) resins is to replace some or all of the styrene with fatty acid-based monomers.  Fatty acid monomers are ideal candidates because they are inexpensive, have low volatilities, and promote global sustainability because they are derived from renewable resources.  This patent-pending technology allows for the formulation of high-performance composite resins with no more than 20 wt% styrenes.  These resins have low viscosities suitable for vacuum infusion methods and have excellent polymer and composite properties.  As a result, these resins are currently being demonstrated/validated under ESTCP WP-0617 for DoD use in Marines HMMWV helmet hardtops, Air Force T-38 dorsal covers, MCM composite rudders for the Navy, and Army tactical vehicles, including HMMWV hoods, HMMWV transmission containers, and M35A3 truck hoods.  The properties and performance of these panels and full-scale parts will be rigorously tested to properly demonstrate this alternative resin technology.  For the truck hoods, the ability of this structure to withstand the static load, cyclic load, high service temperatures, and impact will be demonstrated by simulating the forces the structure would be exposed to in the field.  The transmission container will undergo critical tests to simulate impact, low service temperatures, and assembly, cargo, and storage loads typical during fielding.  The T-38 dorsal cover will be tested as per applicable sections of the Joint Services Specifications Guide 2006 (JSSG-2006).  Following this guide should ensure the proper durability and strength of candidate resins.   The flexural and fatigue properties of the composite rudder will be rigorously tested to assure at least a five-year service life.   Furthermore, each of these parts will be fielded in real service conditions.  The part performance will be monitored for damage and compatibility while being compared to parts made with commercial resins. Current work has validated the commercially produced low HAP vinyl ester resins from Applied Poleramics, Inc.  Furthermore, these resins have been used along with the glass fiber reinforcement used in the MCM rudder and T-38 dorsal cover.  The resulting composite panels have similar modulus, strength, and short-beam shear properties relative to composites made using the conventional high HAP vinyl ester resin.

SUPPRESSING STYRENE EMISSIONS IN UNSATURATED POLYESTER AND VINYL ESTER RESINS
Dr. Tim Pepper, Ashland Performance Materials
(Composites and Tooling Committee/Non-Epoxy)

Federal MACT code and local environmental requirements have made it necessary for fabricators to reduce the amount of styrene emitted from their plants.  In addition to reducing styrene content in resin formulations, fabricators can achieve these reductions through the addition of vapor suppressants. Styrene reduction and suppression options and testing results will be discussed.

FAST CURING POLYUREA SEALANTS:  CONTROLLABLE REACTIVITY WITH COMMERCIALLY AVAILABLE SECONDARY AMINES
Dr. Jay Johnston, Bayer Material Science
(Adhesives and Sealants Committee)
Fast setting polyurea caulks are rapidly becoming the product of choice in high productivity sealing applications and low-temperature sealing applications.  A review of the current state-of-the-art polyurea sealant technology and new secondary amine polyurea technology will be presented. Optimization of polyurea sealant physical properties, UV stabilities, and cure rates will be discussed.

ADVANCES IN INTUMESCENT TECHNOLOGY
Philip S. Rhodes, Broadview Technologies Inc.
(Coatings, Civil Engineering and Flooring Committee)
Over recent years there have been many improvements in the technology for fire protective coatings.  These coatings are currently being employed to protect; structural steel, composite tanks, urethane spray-on insulation, and polystyrene and polypropylene panels.  Intumescent coatings are also being used to slow the burn rate of draperies, mattresses, and wall coverings.

This paper explores how intumescent coatings have improved and discusses the synergies between binders, intumescent additives, fillers, and flame retardants. It will also focus on spray-able, one-pass, thick build epoxy systems, thin-film technology, and flexible fabric backing.

GREEN CHEMISTRY DOES NOT FEAR HUMIDITY IN A FLOOR
Dr. Jean-Luc Dallons, Cardolite Corporation
(Coatings, Civil Engineering and Flooring Committee)
Many different types of systems can be used to coat a concrete floor.  Most of the time, all of them exhibit good properties provided that the surface preparation is correctly made.

In the real world, this is not often the case mainly in terms of the presence of humidity. Humid surface, if present, will be the origin of many problems (loss of adhesion, blistering…).  This paper aims at demonstrating that the applicator/contractor can avoid these problems by using phenalkamine cured epoxy primers.

ORGANOFUNCTIONAL SILICONE RESINS AS HIGH-PERFORMANCE EPOXY CURATIVES
Dr. Mustafa Mohamed, Dow Corning Corporation
(Adhesives and Sealants Committee)
To improve the mechanical and chemical properties of thermoset epoxies, organosilanes are widely used as adhesion promoters, coupling agents, and filler dispersion aids. Silicone resins (non-linear polysiloxanes) feature resistance to temperature extremes, moisture, corrosion, and weathering. Epoxy formulations containing silicone resins have been reported and showed improved performance. We have prepared new organofunctional silicone resin curatives and studied them in several epoxy compositions. Results showed improved toughness, moisture stability, and overall performance. In this presentation, we will discuss the results and application of amino-functional silicone resins in epoxy formulations.

GLOBAL EPOXY INDUSTRY:  PROSPECTS AND CHALLENGES
Jule Mongeluzi, Dow Epoxy
A market overview traces the industry's evolution from 2001 to today - from weak demand and returns below re-investment levels to tightening supply and improved margins.  An understanding of the supply/demand situation for critical raw materials, Bisphenol-A and Epichlorohydrin, is highlighted as a key driver of the industry.  The presentation culminates in a view of the prospects and challenges facing major manufacturers of epoxy resins.

A NEW CYCLOALIPHATIC AMINE FOR COATINGS AND COMPOSITES APPLICATIONS
Dr. Rajesh Turakhia*, Deb Bhattacharjee, John Argyropoulos, Dow Chemical Company
(Coatings, Civil Engineering & Flooring and Composites & Tooling Committees)
A new cycloaliphatic amine has been successfully evaluated for both coatings and composites applications.  This new cycloaliphatic amine is significantly better or comparable in reactivity as compared to other commercial cycloaliphatic curing agents resulting in shorter curing cycle times and improved productivity.  The technical paper will have all the curing kinetics and coatings and material properties. 

JOINING OF MEDICAL PLASTICS USING ATMOSPHERIC DISCHARGE PRETREATMENTS OF ADHERENTS PRIOR TO ADHESIVE BONDING
Rory A. Wolf, Enercon Industries Corporation
(Adhesives and Sealants Committee)
The joining of medical plastics for devices is becoming more complex and more sophisticated, both in performance specifications and structural complexity. Whether used in the form of instrumentation or surgical tools, for diagnostic monitoring or therapeutic purposes, medical devices typically consist of components and materials that must be joined in some way. Joining processes, such as adhesive bonding with cyanoacrylate, light-curing cyanoacrylate, hot-melt, and light-curing acrylic adhesives have typically been used with typical difficult-to-bond plastics and can provide technical and economic advantages when preceded by surface preparation treatments such as air, flame, and chemical plasma discharges. This paper explores the use of these adhesives and discharge surface treatments in the production of medical devices and reviews specific bond preparation techniques in the medical device manufacturing industry.

CYCLOALIPHATIC EPOXY RESINS
Robert Kultzow, Huntsman Advanced Materials
(Potting, Encapsulation and Electrical Committee)
Cycloaliphatic epoxy resins are a class of materials of choice for a wide variety of electrical, electronic, and structural applications.  Having fully saturated molecular structures, they are ideally suited for use in applications requiring resistance to ultraviolet degradation and electrical arc-tracking. This paper describes the commercially available types of cycloaliphatic epoxy resins, describing their features and applications. Physical property data is provided.  This paper also explores alternate choices in materials for a number of applications.

THERMOSET CURING SCHEDULE AND ITS AFFECT ON THE FINAL PROPERTIES
Dr. Steve Sauerbrunn, Mettler-Toledo, Inc.
(Composites and Tooling Committee)
Measuring the final modulus of the cured specimen at room temperature is a good measure of the final cure state of the specimen.  Since most of the commercial processes use large batches, it is not economically feasible to run large batches to test cure schedules.  The average Dynamic Mechanical Analyzer (DMA) is ideally suited to measuring the modulus during the cure, but the sample’s stiffness becomes too large for the DMA to measure the same cured specimen back at room temperature.  The DMA/SDTA 861 is capable of measuring the shear modulus of a thermoset resin from the uncured state to the cured state, at high temperature, and the cured state back at room temperature.  This paper will report the results of these tests as the cure schedule is changed.

MIXED MINERAL THIXOTROPES – UNEXPECTED BENEFITS IN A THIXOTROPE FOR SMC APPLICATIONS
Terry Brennan, Southern Clay Products
(Coatings, Civil Engineering and Flooring Committee)
A new class of additives has recently been developed by scientists. These new additives are called mixed mineral thixotropes (MMT’s). MMT’s are characterized by ease of handling, ease of incorporation, high efficiency, and very high performance to viscosity ratio. Data will be presented that show the efficacy of MMT’s in preventing stratification of both light and heavyweight fillers in SMC applications, including homogenous spacing of micro balloon fillers. MMT’s also improve the tendency of SMC products to “squeeze out” during processing. These benefits are delivered in a product that has minimal effect on the processing viscosity of the SMC formulation.

TOUGHENING OF EPOXY INFUSION RESINS FOR COMPOSITES (Continued)
Stephen C. Nolet, TPI Composites Inc., and Douglas J. Sober, Kaneka Texas Corporation 
(Composites and Tooling Committee)
Many new composite applications for epoxy resins are for large or very large structural parts. Windmill rotor blades, bodies for people movers such as trains and buses, boats, and military troop transport are ideally suited for manufacture by resin infusion (SCRIMP®) techniques. To be successful, these large parts need improved physical and thermal properties over current systems available. Many toughening agents already exist for epoxy resins and novel modifiers have been introduced to the marketplace recently.

TPI Composites Inc. and Kaneka Texas Corporation have conducted a joint project to examine the physical and thermal properties of several toughened resin systems at various loadings of modifiers. The base premise was that the resin system was to be epoxy-based and capable of being infused by the SCRIMP® process. The testing was conducted on neat resin castings as well as epoxy-infused glass and carbon fabrics including both uni-directional and multi-axial reinforcements.  Performance properties to be evaluated included thermo-mechanical properties, tensile and compressive properties, fracture toughness (K1C and G1C), compression after impact (CAI), tension/tension fatigue, compressive strength, and others. This paper will discuss the test design including the various reinforcements and tougheners incorporated into the epoxy matrix as well as the final test results of the composite parts.

WOOD COMPOSITE OVERLAY
Atta Zaghloul, Zeraus Products Inc. in cooperation with CPD Construction Products 
(Coatings, Civil Engineering, Flooring Committee)
"Wood composite overlay" is an effective and innovative approach to rejuvenate and beautify aged wooden decks without having to consider the costly alternative of deck replacement.  It is a multi-layer system that is a liquid applied and cured - in - situ to form composite thermoset plastic.  It consists of a highly penetrating "fortified" epoxy sealer, 30-40 mils thick self-leveling epoxy mortar, and protective non-slip aliphatic polyurethane.  The combined composite materials move together with the natural expansion and contraction of wood boards, reinforce and encapsulate them from moisture and rotting, and maintain their structural integrity.