Under the development trend of the most environmen

The development trend of environmentally friendly plastic products (2)

(2) fully degradable plastics

1, development and application of fully degradable plastics

1) starch

thermoplastic starch manufacturing film and garbage bag industrialization, such as ecopol film in Czech Republic and BIOflex film in Italy

starch foamed plastic balls, ropes, strips, sheets, vacuum forming containers and trays have been commercialized as substitutes for polystyrene foamed plastics. For example, amylun, nationalstar & Chemical and D in the United States need to be equipped with large punctuation elongation devices aniels, novon and in International; Biotec, storopack, sunstarke, novamont, paperfoam in Western Europe; Asian companies such as japancorn.starch, ァイセセセセセセセセセセセァイセセセセセセセセセセ; Championinternational made starch fiber with excellent mechanical properties

2) cellulose derivatives

Japan, Russia and the United States have carried out research on biodegradable plastics with cellulose derivatives as the main body. Shikoku Industrial Technology Testing Institute of Japan, physical and Chemical Research Institute of Japan, Xichuan rubber industry company, etc. have obtained casting film, facial tissue paper, foaming materials, etc. respectively

3) polylactic acid polylactic acid (PLA)

is smoked with corn, wheat, cassava and other starch as raw materials. After enzymatic decomposition, glucose is smoked. After fermentation by lactic acid bacteria, it is transformed into lactic acid. Finally, lactic acid is chemically synthesized to obtain high-purity polymers. At present, there are two main methods for the synthesis of PLA: ① direct polycondensation; ② Ring opening polymerization of lactide. The direct polymerization process is simple and the amount of chemical raw materials and reagents is small, but the molecular weight of the polymer is still low. The ring opening polymerization of lactide is an indirect method. The synthesis process is to take lactic acid as raw material, prepare lactide in the presence of initiator or catalyst, and then prepare PLA and its copolymer by ring opening polymerization of lactide in the presence of catalyst. High molecular weight (700000-1million) PLA can be obtained by this method, but the process is complex and the cost is high. At present, the United States, Germany, Japan, Finland, the Netherlands and other countries have achieved the industrialization of polylactic acid. Cargill Dow of the United States, with an annual output of 140000 tons, polylactic acid products are used in packaging, textiles, disposable plastic products and other fields

in 1998, Germany realized the commercialization of PLA boxes. In Japan, the annual output of Unica, Zhongfang, Toray, Mitsui chemical and other companies is less than 10000 tons, of which Toray is cooperating with cargilldow in spinning development. In addition, Denmark, Canada, South Korea and other countries are also conducting research on the industrialization of polylactic acid. Domestic Haizheng group has realized the industrialization of polylactic acid

4) polyhydroxyalkanoates (PHAs)

phas can be prepared by two methods: ① taking starch as raw material, it is produced by biological fermentation (such as true Alcaligenes); ② Using alkanes as carbon source, PHAs with different structures were prepared by changing the control conditions of carbon source and Pseudomonas culture process

Austrian Linz chemical group and Austrian Biotechnology Co., Ltd. use Alcaligenes hypertrophy with molasses as raw materials, with an annual output of 20 tons of PHB. The former British Imperial Chemical Company ICI commercialized PHB and PHBV, with the brand name biopol. Brazil phbindustrals/a company has an annual output of 50 tons. Mitsubishi Gas Chemical Company of Japan produces 10 tons per year. The aliphatic polyester PHB (polybutylene succinate) produced by Showa polymer in Japan is used for shopping bags, agricultural films, plates, etc. after being modified by isocyanates, the rigidity and thermoplastic of the material can be improved. Domestic Tian'an biomaterials Co., Ltd. has a PHBV production capacity of 1000 tons/year

5) copolyester

Mitsubishi Gas Chemistry (MGC) of Japan produces carbonated polyester (PEC), whose melting point is 110 ℃, and its performance is similar to that of PP Homopolymer. It is used by Sony in tape packaging. The aliphatic aromatic random copolyester (ecoflex) manufactured by BASF company in Germany does not need to be dried before processing. When it is processed below 230 ℃, it has good melt stability and tensile properties. It can produce a 10m thick film, which has good barrier properties to oxygen and water vapor and excellent price performance ratio

Inner Mongolia Mengxi company built a 3000 ton annual production line of carbon dioxide and propylene oxide copolymer (PPC) synthesis at the end of 2002, which is currently mainly used in packaging and medical materials

2. Completely degradable plastic recycling treatment

IV. development trend of environment-friendly plastics

(I) production technology innovation

1, recycled plastic recycling technology

1) reduction/energy saving technology, such as new microporous molding technology, auxiliary molding technology, shape control technology, low-pressure molding technology, composite molding technology

2) homogenization/ontology technology general discussion on the challenges and Countermeasures of food contact household appliances under the new national standard, such as high-performance technology of materials, hole compatibilizer, filling modification, dynamic crosslinking, nanocomposite and other snow and plastic assembly technologies

3) recycling and sorting technologies of recycled plastics, such as electrostatic separation of waste plastics, electromagnetic separation system, X-ray treatment and separation, and IR sorting technology

4) thermal cracking and energy recovery engineering technology and management system 5) high performance technology of recycled plastics

2. Synthetic modification technology of biological resources polymer materials 1) improve the variety and synthesis process of genetically engineered strains 2) blend modification with other biodegradable materials to improve performance, such as polycaprolactone (PCL), ethylene vinyl acetate copolymer, poly 4-vinyl phenol, polycaprolactone Poly3 hydroxybutyrate, etc

3) filling modification, such as hydroxyapatite (the mechanical strength of PLA/HA composites is 31% higher than that of unmodified composites), - tricalcium phosphate (- TCP snow, montmorillonite clay, layer 9, the charging voltage of hand-held spectrometer battery is 220V, exchange electric silicate, etc.

4) plasticization modification adopts all kinds of low molecular weight polymers, plasticizers High molecular weight peg plasticized and modified PLA, PHBV, PPC, etc. Using amine compounds such as urea, thiourea and guanidine hydrochloride instead of commonly used alcohol plasticizers can promote the gel fumigation of starch and effectively inhibit the aging and embrittlement of starch

5) cross linked modified potato starch was etherified, and water, PVA, glycerol and other additives were added to the modified starch to prepare all starch thermoplastic film. Using glyoxal as crosslinking agent, polyethylene glycol as auxiliary agent and modified starch as main raw material, all starch film can be prepared

6) polyimide ester and chitosan prepared from renewable materials modified by composite layer are used for composite layer modification of starch. Polyester starch polyester composite layer has good water resistance. Its products can be used in food packaging or controlled release of drugs, pesticides and herbicides

7) graft and copolymerization modification, such as PLLA PCL PLLA, PLA co PCL copolymer compatibilizers, these compatibilizers can promote the dispersion of PCL in PLA matrix, and improve the mechanical properties of the blend film

3. Production technology of environment-friendly plastic additives

1) synthesis and application technology of non-toxic plastic additives, such as the synthesis technology of oligomers, polymers, decomposition residues, and salts formed with zinc, calcium, magnesium, titanium tin, aluminum and other metals with fatty acid esters, epoxy esters, polyethylene glycol, alkanes, higher polyols, aliphatic amides, polysaccharides, amino acids as the basic structural units

2) synthesis and application technology of efficient and non-toxic composite plastic additives, such as the matching technology between various additives

3) application technology of non-toxic natural mineral filler, such as mineral ultra-fine powder, treatment technology and application technology

4. Molding and processing technology of environment-friendly plastic products

1) new molding and processing technology of water-soluble polymers, such as PVAL, starch, chitosan

2) new molding and processing technologies of fully biodegradable plastics, such as PLA flexible film molding, PLA reinforced and toughened injection/extrusion molding technology, PHAs reinforced and modified product molding and processing, and polyaliphatic carbonate plastic product modification technology

3) light natural fiber filled composite molding technology, such as straw, starch, shell powder filled environment-friendly plastic micro foaming molding technology

4) high performance recycled plastic product molding technology, such as co injection molding, CO extrusion and stretch oriented molding technology of composite products

5) special/special environment-friendly plastic products forming equipment and machinery (II) establish a perfect evaluation and supervision system. 1. Plastic classification standards, such as "definition, classification, marking and degradation performance requirements of degradable plastic sheets", "definition, marking and biodegradation performance requirements of biodegradable plastic sheets", "definition, marking and compostable performance requirements of compostable plastic sheets"

2. Environmental friendly plastic product identification, such as "identification and marking of plastic products"

3. Test methods and technical standards, such as "determination of the final aerobic biodegradation capacity of materials in soil by measuring the oxygen demand in the closed respirometer or measuring the released carbon dioxide", "determination of the disintegration capacity of materials under the conditions of defining the pilot scale of composting", "determination of the final aerobic biodegradation capacity of materials under the conditions of controlled composting adopts the method of measuring the released carbon dioxide"

4. Standardized, institutionalized and procedural laws and regulations for recycling, such as the solid waste disposal law, the resource recycling law, the pollution prevention law, the basic law for promoting the establishment of a circular society, the solid waste management and public cleaning law, the law for promoting the effective use of resources, the law for promoting the classification and recycling of containers and packages, the law for recycling household appliances, the law for recycling of buildings and materials Food recycling law and green procurement law

(III) national industrial policy guidance promotes the establishment of a complete material production system of a circular society

for example, Japan has comprehensively formulated the industrial science and technology development plan of a circular society, including the science and technology development plan and supporting operating systems/regulations in various related fields, and clearly put forward the economic development strategy from technology to environment. The Ministry of agriculture, forestry and fisheries has formulated Japan's biomass strategy

China has also included research projects in relevant fields in the ninth, tenth, 863 and eleventh five year plans, formulated the renewable energy law (Draft), the solid waste law (Revised) and other regulations, and proposed scientific, technological, humanistic and green Olympic projects

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