The brilliance and poverty of Russian biodegradable polymers

Decomposable materials

Oksana PRILEPINA, "Rosatom Country"300 meters from the Kremlin, on more than three hectares of priceless Moscow land, the shabby buildings of the NIFKHI are spread out.

Karpova. Five buildings, the premises of the former workshops and design center, metalworking workshops, warehouses – once Karpovka was reputed to be the leading physico-chemical institute of the country, moving forward world science. On the rusty honor board, instead of photos, there are huge holes through which the lush greenery of an unkempt park makes its way. We are walking with Dmitry Polyakov, head of the polymerization processes laboratory, who has been working at the Institute for 50 years. "Linden Alley was planted by a landowner in the 19th century, he went to the Yauza River to shoot ducks," says Polyakov. – There was a church on the site of our fifth building, and in 1918 a scientific institution was built. The last major overhaul was in 1968." Despite the decadence, it is beautiful here: columns, bas-reliefs with the faces of academics, massive mirrors inside the building, four-meter ceilings. Of the 25 laboratories in Karpovka, three scientific and technical centers have recently been formed, since some laboratories consisted of one to four people. Scientists continue to do what they love, managing to create innovative technologies on the equipment of the 60-80s.

Laboratory of polymerization processesAnd biopolymer threads that are made in NIFHI

Currently, biodegradable materials are being actively developed all over the world – a fashionable topic.

In the West and in the USA there are impressive polylactide productions, natural polymers obtained from grain, cane, corn and vegetables are carefully studied. Karpovka took the path of creating synthetic biodegradable materials. Here, for about 10 years, a new matter has been born from lactic acid. Polymers were originally created for medicine. Threads that dissolve themselves in the body after surgery have already become familiar. In domestic hospitals, metal staples, pins, screws, spokes are still used for complex fractures, which in most cases requires repeated surgical intervention to remove the devices. Bio-fasteners perform their function no worse than metal, but when bones fuse, polymers decompose into carbon dioxide and water. 

Gird the Earth three timesIn Karpovka, back in the 90s, they tried to produce pins from polyglycolide for splicing bones and threads of any thickness up to the minimum - for stitching nerve tissues.

Together with the Institute of Surgery named after Vishnevsky proved that our materials are no worse than foreign ones. Together with the Institute of Traumatology, Orthopedics and Military Field Surgery (Chernivtsi), they conducted successful clinical trials on 65 patients, received permission from the Ministry of Health for industrial production, but they did not have time to launch production in the prescribed three years – they did not find money.

Until now, both threads and products for fixing bones are imported to Russia, although there are their own scientific developments. "The production of surgical thread can fit on two tables, the equipment is simple," says Dmitry Polyakov.– Because of its small size, it is even difficult to call it industrial. From 1 kg of polyglycolide, so many threads are obtained that they can encircle the globe three times." The surgical thread resolves after 1.5 months, the pins hold the strength for four months. NIFHI studies have shown that the polymer decomposition time can be programmed and used in the production of long-acting drugs. A concentrated medical preparation is placed in a shell of a biodegradable substance, injected into the body – and the medicine is given out in the right portions at the right time. "The lifetime of a biopolymer depends on many reasons,– Dmitry Polyakov continues. "It depends on the type, molecular weight, degree of crystallinity, and so on." Long-acting capsules are used very widely in various fields of medicine before and after operations. And there is no alternative to them in the treatment of extensive skin burns, because the worst thing in burns is infections. The Institute suggests applying bandages and cotton wool made of non–woven biodegradable materials with antibacterial impregnation to burns and wounds - then painful bandages are not needed. This property of polymers can also be used in photodynamic therapy in the treatment of almost all types of skin cancer. With the help of a biopolymer, porphyrin is injected into the body, which is concentrated in the affected skin cells. When the accumulated porphyrin is irradiated, the so-called singlet oxygen is generated, which has great activity in oxidation and devours the modified tissue. In the future, the biopolymer can be used in ophthalmology as a kind of glue. The doctor will apply polylactide to the incision, it will tighten the edges of the wound, and you can not sew it. Regenerative surgery is rapidly developing in the world – scientists have already learned how to grow cells, new tissues and even organs. Synthetic biodegradable materials are the best scaffolds – matrices for growing cells. Research in this direction has begun at NIFHI. The first samples have already been given to the Institute of Dentistry and Maxillofacial Surgery. They say that the cells in the new matrices are growing. Whether the state will finance this project of Karpovka and her medical partner will be decided in the coming months.

Miracle Meat GrinderWe go down to the laboratory, where the directorate was located in Soviet times.

Chaos reigns in the room, generated by the tests of a new electroforming unit. Leading employee Sergey Belousov snatches a nondescript rag from somewhere and proudly reports: "This is a mixture of polyamide and polycarbonate polymers, it can be used as a filter. It will easily protect the respiratory tract from such smog, which was this summer, and from radioactive aerosols." The value of nonwoven fabric is not only in the substance from which it is made – in Karpovka, a new production technology was invented in a year. No one in the world, except us, has an installation where it would be possible to fill in monomer granules and immediately get a finished product from a polymer. The know-how is kept secret because the patent has not yet been received. But the general scheme is this. The main part of the installation is the extruder. "Translating into simple language, an extruder is a meat grinder," says Sergey Belousov. "We pour granules of the initial substance, monomer, into it, they melt, turn into a polymer, scroll and are pulled through the thinnest hole by a powerful electrostatic field, weaving such a material."The technology is inexpensive, environmentally friendly, the cost of the product will mainly depend on the polymer and electricity prices. A similar technology is used in NIFHI in the production of "Petal" and "Alina" respirators, but they are based not on a molten polymer, but on a solution. The use of solvent is not only expensive, but also not environmentally friendly, so perhaps these respirators will now be produced in a new way. 

No transparency 

"Rub the sample," Chief Researcher Sergey Chvalun hands me a small blue piece of polylactide, similar to a hard matting. It easily crumbles into fine dust, which will eventually turn into the same CO2 and H2O. I have in my hands the hope of Russia to get rid of bags, bottles and other packaging made of polyethylene and polystyrene, of which we produce at least 2 million tons per year. Time has no power over them, landfills are growing. The US has already sounded the alarm, organized a state program and lowered prices to 3.5 euros per 1 kg of polymer for bio-packaging. But it's still one and a half times more expensive than the usual polyethylene terifluorate. "Our polylactide in the prototype costs $ 3 per 1 kg," says Sergey Chvalun, "you can make several thousand packages from it, the cost of one is a penny. But polystyrene is even cheaper, about 25 rubles per 1 kg. The global trend leads to making packaging from vegetable raw materials, which is not so expensive. We are also thinking of experimenting with grain, beets, corn. This problem is also being dealt with in Krasnoyarsk and in a couple of other places in Moscow." The problems of packaging biomaterial are not only in price, but also in transparency – literally. Of course, bottles, disposable tableware, film for non-food products can be made both cloudy and colored. But the consumer will want to take a closer look at food in supermarkets. However, it is not necessary to immediately switch to expensive biodegradable packaging, you can start working while waiting for the wonderful material to become cheaper. "During the production of the film, a biopolymer can be added to polyethylene, which will be distributed in the form of small inclusions – such a composite material will turn out," explains Dmitry Polyakov. – When the polylactic acid begins to disintegrate, the material will crumble into dust. The resulting polyethylene powder, according to many studies, can be a harmless component of the soil, such as clay granules of expanded clay. So we will gradually switch to environmentally friendly packaging." The head of the laboratory told how a Russian private company tried to buy a plant for the production of a new generation of film, but was faced with a lack of raw materials. We do not have an enterprise synthesizing polylactides. Germany has proposed a production capacity of 30 thousand tons of polymer per year, and it takes at least 100 thousand tons to achieve an acceptable price of products. That's the point so far. Now all hope is for a targeted state program. State policy should be aimed at encouraging manufacturers who produce their goods in biodegradable packages, otherwise in the very near future our cities will find themselves in a ring of landfills. Incinerators are only a partial solution to the problem, since emissions into the atmosphere do not improve the environmental situation at all. Carbon dioxide, the concentration of which continues to increase, is a good illustration of the current weather disasters. 

Science as the meaning of life 

There are a lot of areas of development for biopolymers – there would be enough imagination. At one time, one Voronezh plant received an order for the production of coffins made of impact-resistant polystyrene due to the lack of forest in the region. They made it, but it didn't work, because the product decomposed for too long - 50 years. The prospects are completely different now. Biopolymer matrices are also new, in which various nanoparticles can be restored under the action of radiolysis. "These particles have unique properties: catalytic, optical, electrodynamic," says Sergey Chvalun. – We irradiate the matrix, the nanoparticles grow, and a polymer film filled with silver, hydrogen, gold, and copper is obtained. For example, it is used as a "smart" coating that changes color when irradiated." And yet it is strange to see in what poverty scientific achievements are born. Heads of departments, doctors of sciences at NIFHI receive 10.7 thousand rubles, senior staff – 10.3 thousand rubles. The allowances, if any, are low. Graduates of universities make the most attractive offers – 17-20 thousand, but few go for it. The average age of employees in Karpovka is high, but this is just a plus: a pension is added to the salary. "The scientists who stayed here see the meaning of their lives in science,– says Dmitry Polyakov. – We live with an interest in our favorite business."

Portal "Eternal youth" http://vechnayamolodost.ru21.03.2011