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Technical Papers

The following twelve technical papers are confirmed for presentation at the 2013 Annual Conference in addition to:

Note: Technical papers are listed in alphabetical order by company

SELF HEALING EPOXY SYSTEM FOR OUTDOOR ELECTRICAL APPLICATIONS

Pradip Kumar Dubey, Aditya Birla Chemicals
(Potting, Encapsulation, Electrical Committee)

Conventionally cycloaliphatic epoxies are preferred polymeric insulating materials for medium and high voltage outdoor electrical insulating applications as these provide optimum combination of process and performance properties-mechanical, thermal and electrical combined with high resistance to UV weathering. The performance of these systems is however limited in regions of high humidity involving high precipitation levels and polluted environments wherein the formation of conductive layer causes considerable reduction in insulation performance leading to increased surface leakage current and arching. In recent years epoxy systems providing intrinsic hydrophobicity have been developed by physical or chemical modification of cycloaliphatic resins. These systems also provide hydrophobicity transfer and recovery effect (HTRE) which enables sustaining the performance in long term.

The present study concerns development of self healing epoxy system involving chemical modification of the hardener component of the system instead on the prior arts which involved modification of the resin. Being chemically modified the hardener provides improved storage stability addressing concerns on limited shelf life observed in case of existing systems. Electrical insulating components prepared from the novel self healing epoxy system provide hydrophobicity measured by contact angle and hydrophobicity class, HC1 according to the STRI
classification guide for composite insulators. The self healing behavior of the system is confirmed by destroying the hydrophobicity by exposure to plasma and determining the change in the HC with time. The intrinsic hydrophobic nature of the system enables recovery or self healing within 24 hours.

FORMULATING BEYOND SURFACE DEFECTS CAUSED BY MOISTURE IN AMINE CURED EPOXY

Peter Lucas, Air Products & Chemicals
(Potting, Encapsulation, Electrical Committee)

Epoxy coatings provide excellent protection for a wide variety of substrates. However, if surface contamination is present intercoat adhesion is compromised. The white haze, blush, or water spotting of some amine-cured epoxy coatings is investigated using several analytical techniques. The chemistry of water spotting is identified and suggestions made for amine selection which will avoid this unwanted migration.

FLUORINATED POLYOLS FOR ULTRA WEATHERABLE COATINGS

Kristen Blankenship, AGC Chemicals
(Coatings, Civil Engineering, Flooring Committee)

Fluoroethylene vinyl ether (FEVE) resins were developed in the early 1980’s as alternatives to standard fluoropolymer coating resins like polyvinylidene fluoride (PVDF).  FEVE resins are  hydroxy functional allowing them to be crosslinked with standard aliphatic isocyanates to make fluorourethanes.  Unlike PVDF, which is usually formulated into coil coatings cured at high temperatures, FEVE resins enable the production of both shop and field applied coatings.  They are also soluble in common solvents, enabling production of relatively inexpensive resins.  They offer excellent weatherability, good pigment compatibility, and can be formulated in a wide range of gloss.  By altering the type and number of functional groups, physical properties like flexibility and chemical resistance can be changed.  Solvent grade resins, water based resins, and powder coating resins can also be synthesized.  Typical markets include architectural, industrial maintenance, aerospace, automotive, and alternative energy.

This presentation will briefly review the properties and chemistry of FEVE resins.  New developments in FEVE resins which enable the development of VOC/HAPS-free and water-based coatings will be covered.  Several projects which used fluorourethane coatings based on FEVE resins will then be discussed.

SUSTAINABLE BY DESIGN - INTRODUCING RECYCLABLE EPOXY TECHNOLOGY

Dr. Stefan Pastine, ConNora Technologies
(Composites & Tooling Committee)

Thermosetting plastics used today are not recyclable simply because they were never designed to be in the first place. Yet, there is nothing inherent about the design of thermosets that precludes them from being re-designed to be recyclable/reusable materials.  Connora’s Recyclamine® hardener technology enables any epoxy resin system to be recyclable, and represents a new era in sustainability for thermoset plastics. The technology effectively solves the end-of-life predicament of thermosetting composites and also enables manufactures to extract value from composite production waste.

A general overview of recyclable epoxy technology will be presented, including the underlying chemical principals that enables recyclable epoxy.  Data generated by PPG Fiber Glass in unidirectional fiberglass composites using  early prototype recyclable epoxy hardeners will be presented. Additionally, the range of mechanical & processing properties that can currently be achieved with newly developed hardeners will be presented.

CHEMICAL RESISTANT HARDENERS FOR CIVIL ENGINEERING APPLICATIONS

Krishnan Karunakaran, Dow Chemical Company
(Coatings, Civil Engineering, Flooring Committee)

Epoxy thermosets are often exposed to chemicals like inorganic and organic acids, alcohols, organic solvents, etc. Thermosets having resistance to such chemicals are of practical importance with applications ranging fromindustrial coating, flooring and protective liners. The resistance to various chemicals depends on a number of factors, namely, the type of epoxy resin, hardener and the various ingredients in it, curing projile, etc. In this presentation we will provide the recent developments in this area with special emphasis on amine hardeners designed to provide chemical resistance.

WILL ADHESIVE BONDING EVER REPLACE MECHANICAL FASTENING?

David Nick, DPNA International, Inc.
(Adhesives & Sealants Committee)

This presentation will describe the current status of adhesives as an alternative to mechanical fastening. Beginning in the early 1990’s, the opportunities for chemical (adhesive) bonding were reported as “boundless”. Chemical bonding methods were promoted as the wave of the future, replacing labor intensive and costly welds, screws, nuts and bolts, stitching and tabs for fabricating many components. Today, adhesives have gained market share and are well positioned in many industry segments. Most notable are transportation (aircraft and autos), construction, (flooring, wall panels), woodworking and other assembly sub-segments. Adhesives claim nearly 13% of the $324 billion of the global fastening market and it is increasing. Segment market share gains for adhesive bonding within the global fastening market will be identified along with comments on key market drivers, strengths and weaknesses. Concluding comments will be offered on the future outlook for both adhesive bonding and mechanical fastening.

ACCELERATION OF AMINE-CURED EPOXY RESIN SYSTEMS

Bruce Burton, Huntsman Corporation
(Composites & Tooling Committee)

The choice of accelerators for amine-cured epoxy formulations has often been done as an afterthought, using old accelerator compounds or packages designed for other purposes.   Such an approach to acceleration may eventually create problems in the final products that, in some cases, may never be traced back to the accelerator.  Properly chosen accelerators can be an integral part of fine-tuning the reactivity of such systems and can also serve to beneficially influence other properties such as glass transition temperature, modulus, strength, elongation at break, and chemical resistance.  Accelerators typically increase the reaction rate of epoxy systems by 1) adding, or quickly creating, hydroxyl groups, 2) by increasing the heat generated (thus increasing the temperature) in the system, or both.  If acceleration alone were needed in all cases, one would just use the necessary amount of the fastest accelerator, but other factors, such as cost, toxicity, solubility, processing effects, final properties, regulatory concerns, and ease of use, mean that it can be advantageous to select specific accelerators that are well-matched to specific applications.  Careful pairing of accelerators with slowly reactive amines may allow the use of higher processing temperatures, thereby decreasing the need for expensive epoxy diluents that may decrease thermal and mechanical performance properties.

UNDERSTANDING THE COMBUSTION OF EPOXY-BASED COATINGS USING CONE CALORIMETRY

Andrew Martinez, ITW Polymers Coatings
(Coatings, Civil Engineering, Flooring Committee)

Depending on their application, epoxy-based coatings may be subject to a number of flammability conformance requirements due to their organic content and subsequent combustibility. It is therefore beneficial for the formulator to understand how these materials combust in cured systems so as to comply with imposed specifications. In this paper, a number of commonly employed Bisphenol-A and Bisphenol-F type epoxy resins were cured with various amines onto 4x4-inch steel panels at a thickness of 30 mils and exposed to 50 kW of ambient heat using a cone calorimeter. The amounts of smoke and heat released during these trials were monitored over time. The results obtained provide insight into the nature and extent of combustion of the resins tested, while also supplying the formulator with data upon which to base further adjustments to their formulation.

BRIDGE AND ROADWAY REPAIR IN BROOKLYN: UTILIZING EPOXY COMPOSITES

David White, Sika Corporation
(Composites & Tooling Committee)

 

20% WIND BY 2030: THE ROLE OF GOVERNMENT, INDUSTRY, AND ADVANCED MATERIALS

Steve Nolet, TPI Composites
(Composites & Tooling Committee)

 

RECENT DEVELOPMENTS IN ALTERNATIVE EPOXY RESINS

Dr. Daniel F. Schmidt, University of Massachusetts Lowell
(Coatings, Civil Engineering, Flooring Committee)

Epoxies represent a diverse, versatile and extremely important class of thermosets. That said, there is growing concern over the use of bisphenol A (BPA) in general and in the can coating sector in particular, as well as more and more interest in bio-derived resins. In this talk, a summary of recent efforts to explore alternative epoxy chemistries will be presented. One area of ongoing work relates to the use of epoxidized linseed oil as a basis for a range of rigid and semi-rigid epoxy formulations. Initially aimed at engineered wood products, this work has since expanded to include ongoing efforts to create bioepoxy-based glass fiber composites for wind turbine blades, with additional efforts designed to render these and their conventional counterparts fully reworkable and reprocessible. A second area of research has to do with the synthesis, characterization and application of high performance epoxy resins based on 2,2,4,4-tetramethyl-1,3-cyclobutanediol (CBDO) and designed to serve as direct replacements for conventional BPA-based epoxies. Scale-up of this technology is in progress, with relevant application areas including adhesives, composites, and coatings. The overall goal of these projects is the creation of solutions that are not just sustainable but practical and economically viable as well.

INCORPORATING ACRYLATES IN EPOXY-AMINE CURE SYSTEMS IMPROVES ADHESION

Dr. Yuan Chieh Chu, Valtech Corporation
(Adhesives and Sealants Committee)

An epoxy-amine cured system can be fast-curing at the measurement of 100-200 gram mass due to its high-exotherm and auto catalyzation. When an epoxy-amine system is applied as a thin film or as a thin layer adhesive, the exotherm heat is dissipated into the substrate. The cure time reaction is much slower without the excess heat generated during cure. Incorporating an acrylate demonstrates that through a Michael addition mechanism, the epoxy-amine system does not generate as much heat and the reaction proceeds on its own to shorten the through-cure time.

This paper demonstrates the increase of the reaction rate by the thin layer gel time and the bond strength and hardness build up with the cure time. The cross linking effect of the muti-functional acrylate is also demonstrated. Resistance of this acrylate containing epoxy-amine system to various solutions is shown to demonstrate the response to the demands of various applications.

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