A more rigid and impact resistant plastic should shortly be available for the manufacture of car panels and shock absorbers, electronic equipment cabinets, packaging and an infinite number of domestic utensils. The raw material for the production of these parts is a new type of polypropylene (PP) that is being manufactured on a pilot scale by the company Braskem, a giant in the country’s petrochemical industry. The difference in the new polymer resin to that already offered to the market is that it possesses nanometric structure and results in greater impact and breakage resistance. Using nanotechnology resources, a new multidisciplinary area that deals with and produces structures at the level of nanometers, a measurement represented by 1 millimeter divided by 1 million, the company has obtained this new material by way of a partnership with the Chemistry Institute of the Federal University of Rio Grande do Sul (UFRGS). “We make use of a type of clay in nanometric form that disperses itself and joins up with the molecules of the polypropylene and confers greater rigidity to the final product”, advised professor Raquel Santos Mauler, the research coordinator.
The clay used is composed of minerals, known as betonite and montmorilonite, which come layered. In the process, developed by the UFRGS and company researchers, the stacked up layers of clay dispersed to a thickness of 1 nanometer by the polypropylene, fix themselves onto the resin molecules and form a material called a nano-composite. “The new material endows the final product with 30% more rigidity and four times greater impact resistance”, advised Braskem’s nanotechnology manager, Manoel Lisboa da Silva Neto, who is working with a group of eight researchers, four of them with their doctorate degrees and four technicians dedicated to this area at the company’s Innovation and Technology Center in the town of Triunfo, close to Porto Alegre city. They make up part of a group of 170 people who are working in the same Center.
The first product to be tested with the nano-composite resin was the external structure of a thermal jug produced by the company Termolar, also from Porto Alegre. “The results were very good”, advised manager Silva Neto. 10 liter buckets have also been produced that have proven to have greater resistance. “We’ve passed on the resin to other manufacturers of plastic products, but as yet we can’t say who they are because of confidentiality agreements”, advised the Braskem researcher, Susana Liberman. “With the improved properties of polypropylene the use of this resin widens as in the substitution of another polymer of higher cost, namely acrylonitrile-butadiene-styrene (ABS), used in the cabinet structures of electro-electronics or in washing machines.”
The wagering on nanotechnology as an impulse factor in innovation started within the company during 2003. “One of our functions is to accompany that which is happening throughout the world in the area of plastic resins. In 2002 we had already perceived the new tendencies in resins, principally in relation to polypropylene. The following year we entered into a partnership with the UFRGS and during 2005 we registered out first patent about the nano-compound and then in December of 2006 it was the turn of four other patents, one of them being registered abroad”, explained researcher Susana. “We already maintain a close relationship with Braskem, who have master’s degree and doctorate degree students studying at our institute. With this interaction they get to know that we’ve been working with nano-composites, but as well in other polymers”, stated professor Raquel.
The system of the incorporation of the clay into polypropylene is also going well using polyethylene (PE), another polymer resin equally used in manufacturing domestic utensils and electronic apparatus and car parts. Contrary to the situation with PP, in which the clay is added after it is ready and diluted, the production of PE forming a nano-composite occurs during the polymerization process. “We developed a process in which we produced the PE with ethene, clay and a catalyst (a substance that speeds up the chemical reaction) within the polymerization reactor vessel”, advised Osvaldo de Lázaro Casagrande Júnior, a researcher at the UFRGS.
The production process for polyethylene is occurring on the laboratory scale and as yet has not been tested in final products, ready for the consumer. The greater mechanical resistance could improve the fuel tank of automobile vehicles and substitute some car parts and gearing, also making them lighter. For researcher Casagrande, the more rigid PE could have more top class uses such as the substitution of titanium in prostheses, making these devices cheaper, as well as more specific uses such as the coating of tipper trucks, which transport earth and stones, and shelters for dock quays, in the location of ships’ moorings.
The company has invested R$ 5 million in the development of this new technology and forecasts that at the start of sales the prices will rotate around 30% more than the traditional resin. The main consumers are the companies that transform the resins into plastic products. Still in 2007, Braskem hopes to produce 10,000 tons of PP with the nano-composite, a volume that should double every six months until it reaches 100,000 tons per year, a total sum considered by the company as the potential of these new resins. Currently the company is producing 1.3 million tons per year of polypropylene and polyethylene and is the leader in this market in Latin America.
One of the problems that the company must resolve over the next few years is making a national clay available because that used up until now is imported. There are possibilities of a mine of this mineral in Paraíba State and studies exist on national clays being developed at the Multidisciplinary Center for the Development of Ceramic Materials (CMDMC), coordinated by professor Elson Longo, from the Paulista State University (Unesp), of Araraquara. Collaboration between this Center and the other UFRGS groups, as well as coordination by professor Raquel, and Embrapa Agricultural Instrumentation Unit of Sao Carlos, has strengthened Braskem’s intention to invest in studies with nanotechnology.
After the technologically good results with the new products, the company is researching the adoption of other nano-composites in another type of polymer, namely polyvinylchloride (PVC), also to improve its resistance. Another line of research is to add nanotubes of carbon to polypropylene. These nanotubes are rolled up sheets of carbon with the thickness of an atom that present high resistance to breakage, greater even than that of steel. They can also carry, for example, enzymes in their interior and indicate, in the case of a food package, what is inside it, and whether or not there are any alterations in the consistency and validity of the product. “This is an intelligent packaging line that still requires lots of tests and the verification of its economic viability”, advised researcher Susana.Republish