One of the groundbreaking companies in specialty chemicals, Kenrich Petrochemicals Inc. has been a vanguard in developing products for the polymer industry.
The company has turned its expertise and long history of developing industry-leading compounds to the area of graphene and making the “wonder material” even better.
Kenrich recently joined The Graphene Council as a Corporate Member and we took that opportunity to interview Salvatore J. Monte, the president of Kenrich, to learn how Kenrich became involved in graphene and where the company expects graphene development to go in the future.
Q: Can you describe the genesis of how Kenrich started to look at graphene for its specialty chemicals portfolio?
A: The name Kenrich comes from three graduates from the University of Kentucky who planned to get rich by selling a unique aromatic resin/polymeric plasticizer called 'Kenflex® A', produced at Socony Mobil’s R&D laboratories in Paulsboro, NJ via a formalite condensation polymerization of certain gasoline bottoms consisting of polycyclic aromatic hydrocarbons.
In 1959, DuPont approved Kenflex® A for use in Neoprene® and Hypalon® rubber high voltage wire and cable insulation compounds. The aromaticity worked well in dispersing carbon black and metal oxides. As a result, Kenrich also got into the business of making paste masterbatches of the metal oxides and other raw materials used to accelerate and cure the rubber insulation compounds.
Kenrich’s current President Sal Monte had married Erika Spiegelhalder, the daughter of the owners of Kenrich Petrochemicals, Inc. and was made VP when he joined the company in April of 1966. At the time, Monte was a licensed P.E. He went back to school and in 1969 obtained a M.S. degree in Polymeric Materials at NYU Tandon School of Engineering.
In 1973, the first titanate coupling agent was invented in an effort to make a good dispersion of 85% of a fine particle ZnO in a naphthenic oil base. Monte tested most of the then known surfactants and could not obtain a satisfactory dispersion. Frustrated, he had the Kenrich Bayonne, NJ laboratory synthesize a titanate coupling agent by transesterifying 3-moles of isostearic acid with 1-mole of Tetraisopropyl titanate. The resultant titanate dubbed “Ken-React® KR® TTS” worked “best ever” on the ZnO and all the other inorganics and organics such as carbon black in the various masterbatches the company was producing.
KR® TTS is 2019 EU REACH registered in 680-cosmetic and sunblock formulations based on ZnO and TiO2. As an example, a 55% masterbatch of the ZnO was made smooth and creamy with just 0.5% additive.
The titanate coupling agents evolved into a distinct product line with 64-commercial titanate and zirconate products under the Ken-React® tradename. They proved to work where silane coupling agents didn’t in compositions like CaCO3 filled Polypropylene. The first published technical article on the material appeared in the December 1974 issue of Modern Plastics Magazine with the title: “A New Coupling Agent for Polyethylene”.
Keep in mind that this article positioned Kenrich’s titanate and zirconates as an alternate coupling agent technology to silane coupling agents that were used in the 1950’s to develop the Corvette glass reinforced polyester composites and that initiated the generation of “plastic” automobiles. Silanes worked well on silica/fiberglass but did not couple to carbon black and carbon fiber since carbon does not have hydroxyl groups for silane hydrolysis coupling mechanisms. The producers of silanes state their non-functionality with carbon interfaces in their literature.
Monte went on to write a 340-page book, filed 31-patents worldwide, and wrote over 450-ACS CAS Abstracted “Works by S.J. Monte” and was voted a Fellow of the Society of Plastics Engineers in 2004 around the same time when Professor Sir Andre Geim and Professor Sir Kostya Novoselov of the University of Manchester discovered and isolated a single atomic layer of carbon for the first time known as graphene.
Efforts to make thin films of graphite by mechanical exfoliation started in 1990, but nothing thinner than 50 to 100 layers was produced before 2004. The term graphene was introduced in 1986 by chemists Hanns-Peter Boehm, Ralph Setton and Eberhard Stumpp. It is a combination of the word graphite and the suffix -ene, referring to polycyclic aromatic hydrocarbons. Monte did his M.S. thesis on the synthesis of polycyclic hydrocarbons such as dimethylnaphthalene in the presence of formaldehyde and sulfuric acid clay catalysts to make a better Kenflex® A.
In the early 1960s, Dr. Akio Shindo at Agency of Industrial Science and Technology of Japan developed a process using polyacrylonitrile (PAN) as a raw material. This had produced a carbon fiber that contained about 55% carbon. In 1960 Richard Millington of H.I. Thompson Fiberglas Co. developed a process (US Patent No. 3,294,489) for producing a high carbon content (99%) fiber using rayon as a precursor. These carbon fibers had sufficient strength (modulus of elasticity and tensile strength) to be used as a reinforcement for composites having high strength to weight properties and for high temperature resistant applications.
In 1988, Kenrich and General Dynamics wrote a SAMPE technical paper comparing the property improvements in glass, carbon, and Kevlar® fiber reinforced thermosets demonstrating significant improvement and maintenance of mechanical properties of various polymeric compositions. The maintenance of tensile strength of long carbon fibers in anhydride cured epoxy subjected to 240-hour 10% salt water boil—and other thermosets tested—were quite revealing as they were 5 to 7 times stronger than the control with less than a 3% loss in original properties. In other words, the carbon interface with a polymer was not deteriorated due to the presence of the zirconate and titanate coupling agents.
Part of this resistance to deterioration of the carbon/polymer interface is a result of the neoalkoxy coupling mechanism of the patented Ken-React® zirconates and titanates as they couple via proton coordination with the hydrogens and hydroxyls on the carbon interface to form 1.5-nanometer atomic monomolecular layers in the absence of water with no leaving groups. This is in contradistinction to silanes, which need water and leave water at the interface after coupling.
In simple layman terms, if graphite is the unsliced bologna then graphene are its one-molecule thin slices. The physics of fiber reinforcement materials such as graphite, fiberglass and aramids work on a simple reinforcement principle: Any composition subjected to direct compression forces will act as a column with no bending stresses if the ratio of the length of the column to the diameter of the column is less than ~ 15:1. Once the column becomes longer, bending forces come into play. It’s why the Romans built fat columns and round arches. For example, concrete has 3,000 psi compression strength and only 300 psi bending strength and that’s why steel rebars are inserted in concrete beams to carry the bending loads. The reinforcement that carbon fibers bring is in proportion to their length over diameter ratio. Graphene provides the greatest reinforcement because it is the ratio of its thinness over its cross sectional area.
Kenrich has worked with conductive carbon black for silicone rubber for decades. And in early rubber experiments before graphene was created, Kenrich could disperse carbon black with its titanate and zirconate additives as discussed in the 340-page Ken-React® Reference Manual.
Q: How are you currently incorporating graphene into some of your products?
A: We don’t make graphene or graphene-reinforced products – we make graphene work better. Researchers work with our products using graphene. The Chinese are copying a lot of my old literature and using a lot of the older titanates.
I am much complemented in China and totally ripped off in Japan under a forced licensing of IP to Ajinomoto in an attempt to gain access to the Japanese microelectronics market in the late 1970’s-early 1980’s. For example, all the magnetic recording media and digital copier toner uses my pyrophosphato titanates to eliminate tape hiss and blurred reproduced images.
We have been doing nanotechnology from the beginning – and graphene is an extension of that work in fulfillment of my mission statement: To make more efficient use of raw materials using titanium and zirconium chemistry.
Q: How are you sourcing your graphene and what basic types of graphene are you using to create your compounds?
A: We have a full program established with Matthew McGinnis, PhD and Jeff Bullington and will be working with them at Garmor Inc.’s labs in Orlando by MCO airport, which is 20-minutes from my house in Oviedo, FL.
Q: You have worked extensively with carbon black in applications such as Neoprene. Could you explain some of the benefits and challenges that graphene offers over carbon black in those applications in which both can be used?
A: We can compatibilize the interfaces of almost any dissimilar materials – even Addition and Condensation polymers without fillers.
We have recently been awarded a patent compatibilizing oil (polycyclic aromatics - #4 fuel oil) soaked seawater sand with ordinary Portland cement. Graphene has great potential to make any composition stronger – even concrete – and the solutions are at the nanocarbon interface.
Q: What has proven to be the biggest challenge in incorporating graphene into your products?
A: We believe we will achieve complete deagglomeration of Garmor’s graphene oxide and keep it stable in suspension to take full advantage of its geometry.
Q: Do you anticipate that Kenrich will be using graphene for other products in the future, or do you believe you have already explored all the possibilities for it in your product line?
A: Graphene needs an effective coupling agent in the 21st century such as the mentioned titanates and zirconates, just as silanes did in the 1950’s for fiberglass composites. The work has just begun.
Q: What are your expectations for the commercialization fo graphene over the next 5 to 10 years?
Graphene will grow significantly once the interfacial coupling agent art becomes part of the fabric of the industry.