Biodegradable polymer materials and modifying additives: state of the art. Part I

T he global environmental problem of our time is the accumulation of wastes of polymer materials in the biosphere. Worldwide, nearly 380 million tons of plastics are produced annually [1]. About 9% is recycled, about 12% of polymer waste is incinerated [2–4]. The remaining 79% end up in landfills that occupy huge areas and remove millions of hectares of fertile land from agricultural circulation.

The problem is compounded by the fact that, due to improper burial, almost 12 million tons of plastic are carried annually by rivers into the seas and oceans [5]. As a result, the Pacific Ocean formed the Great Pacific

Garbage patch, the area of which, according to experts, is about 1.5 million square kilometers.

There are two main areas of solution: disposal of plastic waste and creation of biodegradable plastics [6–8].

The main ways to reduce the volume of synthetic plastic waste are incineration and recycling [9–11]. However, burning does not fundamentally improve the environmental situation. Moreover, the combustion of polymeric materials is an expensive process accompanied by the release of highly toxic contaminants (dioxins, furans, etc.) [12–15]. The processing of polymer wastes results in a higher cost of the material, while the quality of the obtained polymer decreases [13–18].

The development of new technologies aimed at the production of environmentally sound materials and

DEVELOPMENT OF NEW POLYMER MATERIALS

о 2018        2019

• Bio-based/non-biodegradable • Biodegradable

Fig. 1. Production capacity of bioplastics in 2018–2019, thousand tons

Source: European Bioplastics Institute excluding emissions of pollutants, as well as integrated waste treatment, are consistent with the concept of environmentally sound sustainable development of human activities adopted by the UN at the Conference on Environment and Development back in 1992 [19–20].

Giving traditional polymers the ability to biodegrade under the influence of microorganisms and natural-climatic factors will significantly reduce the volume of poly-

mer waste and, thereby, improve the environmental situation.

The optimal solution is the development of self-destructing polymer materials, especially for products with a short life cycle (packaging materials, disposable utensils, pens, razors, transport pallets), which must maintain technological characteristics during storage and operation, after which, under the action of certain factors (microorganisms, light, oxygen air, water), must decompose in a short period of time.

Existing biodegradable bio-based polymers are more expensive than synthetic polymers [21–22]. Therefore, biodegradable polymeric materials are mainly obtained by mixing thermoplastic synthetic polymers and biodegradable fillers of natural origin.

Currently, the production and consumption of bioplastics is only about 1% of the total amount of PM [23]. As demand and applications grow and new more complex biopolymers emerge, the bioplastics market grows and diversifies.

According to the latest data from the European Bioplastics Institute (European Bioplastics) and the novaInstitute Research Institute (Hürth, Germany), the global production capacity for the production of bioplastics in 2019 amounted to 2,114 million tons (Fig. 1) [23].

The main applications in the bioplastics consumption market are constantly changing. However, packaging remains the largest field of application of bioplastics, in 2019 it accounted for more than 53% (1.14 million tons) of the entire bioplastics market [23]. Segments, such as automotive/transport and construction, significantly increased their share in 2019 (Fig. 2).

Fig. 2. Production capacity of bioplastics by application industry in 2019, thousand tons

Source: European Bioplastics Institute

DEVELOPMENT OF NEW POLYMER MATERIALS

Table 1

Major producers of biodegradable PM

№	Producer	Product Name and Application
1	Archer Daniel Mildland Со. (USA)	Polylactides, polyhydroxybutyrates
2	BASF AG (Germany)	Polyesters of Butane-1,4-diol, terephthalic and adipic acids Ecoflex, Eastar Bio, additives for the production of biodegradable plastics
3	BAYER AG (Germany)	Polyester amides ВАК – thermoplastic polymer, like conventional thermoplastics for injection molding, extrusion, fiber production
4	Biotec Gmb H. (Germany)	Starch filled plastics “Bioplast” for compost bags, dishes, forks, spoons, cups
5	Cargill Inc. (USА)	Polylactides Eco-PLA for injection molding, thermoforming, production of nonwoven fabric
6	Chronopol (USА)	Synthesis of polylactic acid
7	CSM N.V. / Cargill Inc. (Holland)	Polylactides
8	DAICEL Chem. Ind. Ltd (Japan)	Composites based on polylactide, cellulose acetate
9	Du Pont Co. (USА)	Polylactides from milk, cheese and corn ECO Chem., Copolymer with polyester – Biomax
10	Ecolean (Sweden)	Packaging and equipment for filling liquid food products into branded “jugs”
13	EPI Environmental Technologies Inc.	Raw materials for the production of oxo-biodegradable packaging
14	GREENSAN LIMITED Srls (Italy)	Compostable packaging for food and industrial products
15	Hoechst Trespaphan (Germany)	Biophan Poly-α-Hydroxypropionates for Film Materials
16	Kanebo (Japan)	Bellfree, Lacton poly-α-hydroxypropionates for granules, threads, film materials
17	Mitsubishi Plastics (Japan)	Ecoloju Poly-α-Hydroxypropionates for Film Materials
18	Mitsui Chemicals (Japan)	Lacea poly-α-hydroxypropionates for granules, film materials
19	Mitsui Toatsu Chem. Ltd (Japan)	Products based on starch and polylactide
20	Monsanto Co. (Italy) / ICI. Zeneto Ltd (Great Britain)	Copolymer polyhydroxybutyrate-valerate for the production of bottles, toothbrushes
21	Nature Works (USА)	Ingeo™ polymers for products from coffee capsules and electronics to diapers and napkins. Vercet™ lactides for CASE products (coatings, adhesives, sealants and elastomers), toners and surfactants
22	NESTLE OY Chem. / Pri-malco (Finland)	Polylactides and starchy plastics
23	Novamont (Italy)	Produces "Mater Bi" for injection molding, obtaining films from starch
24	Planet Polymer / Nippon Mitsubishi (Japan)	20 types of Enviro Plastics water soluble, compostable, photodegradable injection molding resins, Aquarbo – polyvinyl alcohol for medical blown films, waste vessels
25	Procter & Gamble (France)	Nodax polyhydroxyalkanoates for nonwovens, films and fibrous materials
26	Roquette (France)	More than 650 by-products from corn, wheat, potato and pea starch
27	Rohm and Haas Co. (USA)	Polyaspartates, water-soluble dispersants, biodegradable dispersants for washing powders
28	Shell Chem. Co. (Great Britain)	Several biodegradable polyesters
29	Shimodzu Co. (Japan)	Transparent, colorless improved Lacty polylactides for injection molding
30	Silbo (Poland)	Cellulose packaging, new bio-compostable packaging standards
31	Showa Denko (Japan)	Bionolle special aliphatic polyesters, polybutylene / succinate and polybutylene / succinate / adipate copolymers
32	Solvay S. А. (Belgium)	Polylactides for a wide variety of applications
33	Sukano (Switzerland)	Masterbatches of additives and colorants for biodegradable polymers PLA and PBS
34	Sunkyong Ltd. (Korea)	Aliphatic polyesters Sky Green
35	Total Corbion PLA (Netherlands)	Luminy® PLA polylactic acid (PLA) and lactide monomers are high temperature and standard grades for a wide range from packaging to consumer products, fibers and automobiles
36	Union Carbide Corp. (USA)	Major supplier of high molecular weight polylactides for the production of films and sacks for food waste, also high molecular weight, water-soluble and biodegradable polyester Polyox

DEVELOPMENT OF NEW POLYMER MATERIALS

Fig. 3. Production capacity of bioplastics by type in 2019, thousand tons

Source: European Bioplastics Institute

Currently, non-biodegradable bio-based plastics account for up to 44.5% of the total bioplastics produced (Fig. 3) [23].

In 2019, bio-based innovative polypropylene entered the market on a commercial scale. PHA (polyhydroxyalkanoates) is the most developing class of polymers, completely obtained from biomaterial and biodegradable, has a wide range of physical and mechanical properties depending on their chemical composition. PEF* (polyethylene furanoate) is a new polymer, which is expected to enter the market in 2023 [23].

Asian countries are leading as a major hub of the entire bioplastics industry. In 2019, 45% of the total bioplastics were produced there (Fig. 4) [23].

Initially, biodegradable PM was a mixture of conventional polymers with starch. Now a whole spectrum of new biodegradable plastics has appeared, differing in production technologies and composition (Table 1).

Among domestic manufacturers of biodegradable polymer products, the following can be distinguished [24]:

• 1)    LLC “Company EuroBalt”, which launched the production of oxo-biodegradable packaging in 2008;

• 2)    JSC “TIKO-Plastik”, producing biodegradable bags with a catalyst additive;

• 3)    DAR PF, certified in October 2009 for production of biodegradable packages;

• 4)    LLC “Artplast”, which began production of biodegradable packaging in June 2010;

• 5)    LLC “Biaxplen”, which launched in 2008 a line capable of producing biodegradable packaging from bioraw materials (potatoes, corn, etc. – bio-materials with a high starch content);

• 6)    CJSC National Packaging Company “PAGODA”, which has biodegradable bags in its range;

• 7)    RT-Khimkompozit has developed the production of biodegradable plastics based on lactic acid. The essence

Fig. 4. Production capacity of bioplastics by region in 2019, %

Source: European Bioplastics Institute

DEVELOPMENT OF NEW POLYMER MATERIALS of this process is the synthesis of monomers by bacteria from available sugars, the decomposition period during composting is from 20 to 90 days.

Thus, the need for compostable bioplastics is growing, as evidenced by the increase in the number of manufacturers of such materials and products based on them. Natural polymers have high biodegradability, biocompatibility and safety. On the other hand, the use of synthetic materials is due to the fact that they can be adapted to obtain the necessary characteristics by using various

manufacturing technologies to reproduce the molecular structure and change mechanical properties depending on needs.

The task of the latest developments in the field of compostable bioplastics is to establish general patterns in the selection of components and technological parameters for the production of materials that combine a high level of operational characteristics with biodegradability, and basic rules for regulating the speed of their safe degradation at the end of service life.