The hottest plapha bioengineering packaging materi

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PLA, PHA - hot spots of bioengineering packaging materials

I. concept of bioengineering packaging materials

what is biomaterial? Due to the rich connotation of biomaterials and the fact that scientists from different fields are engaged in the research of biomaterials, there is no exact definition of biomaterials at present. In a broad sense, biomaterials can be understood as all applied materials related to organisms. According to its application, it can be divided into bioengineering materials, biomedical materials and other biological application materials. According to the source of biomaterials, they can be divided into natural biomaterials and artificial biomaterials. At the same time, the development of materials science makes some materials have both natural and synthetic characteristics. In a narrow sense, biomaterials refer to the materials that can be used to make various artificial organs and medical appliances and products in contact with the artificial physiological environment, namely biomedical materials and biological packaging materials

the biological packaging materials referred to in this paper refer to the packaging materials in bioengineering materials. Its definition refers to the packaging application materials related to organisms using biotechnology. Or Bioengineering packaging materials

Second, the current situation and development trend of bioengineering packaging materials

the contemporary biomaterial industry is developing rapidly, especially the packaging materials and biomedical materials in bioengineering materials

in terms of packaging materials, it is well known that due to human production and living activities, many plastic products that cannot be naturally degraded are abandoned in nature, resulting in white pollution, which is one of the most serious environmental and social problems encountered by countries around the world after industrialization. In the past 50 years, the application of petroleum plastics and various polymers in packaging has increased tremendously. Now the world produces various plastic related materials worth 150billion US dollars every year. Many solutions have been proposed at home and abroad, but most of them can only partially solve the pollution problem or cover it up with the method of pollution transfer. Now many developed countries have passed legislation to industrialize technology research platforms and teams, which are relatively lacking to reduce the use of non environmentally friendly plastics. China has also made corresponding regulations. In many provinces and cities, such as Beijing, Heilongjiang, Liaoning, etc., the use of disposable foamed plastics has been banned by legislation. On December 28, 2001, the State Economic and Trade Commission, the State Administration of quality supervision, inspection and quarantine and the State Environmental Protection Administration jointly issued the "notice on strengthening the law enforcement and supervision of the elimination of disposable foamed plastic tableware", which provides a good opportunity for the development and use of biodegradable plastics. At the same time, the worldwide oil shortage is also a favorable driving force to promote the sustainable development of biological packaging materials to the market. Compared with biological packaging materials, contemporary biological materials have become more industrialized, and biomedical materials and products have accounted for half of the global medical device market share. In developing countries such as China, the growth of biomedical materials is faster

it is estimated that after the listing of engineered tissues and organs, a new market of US $80billion can be opened up. It is expected that in the next 15-20 years, the biomedical materials industry will reach a scale equivalent to the drug market share. At the same time, as the frontier research of biomaterials continues to make progress, it will open up a broader market space and provide guidance for the improvement and innovation of conventional materials

$page break $3. Several types of bioengineering packaging materials that have become hot spots

among biomaterials, synthetic biomaterials are the earliest and most studied, and bioceramics, inorganic materials, metals and alloy materials are also studied more, among which metal materials have been used the earliest, with a history of hundreds of years. Hydroxyapatite is another kind of synthetic biomaterial that has been studied more now. It is the main inorganic component of mammalian hard tissue. Since the 1970s, Hideki Aoki of Japan and Jarcho of the United States successfully synthesized hydroxyapatite, it has become a research hotspot of hard tissue repair materials

with the improvement of people's requirements for environmental protection, but also in response to the requirements of biomaterials' own biodegradation, natural and semi natural biomaterials have attracted more and more attention. Natural biomaterials are natural materials formed by biological processes, such as shells, bones, teeth, silk, spider silk, wood, eggshells, skin, tendons, etc. Because biomaterials have evolved over thousands of years, their unique structure leads to many excellent comprehensive properties of natural biomaterials compared with synthetic materials. Among many such materials, polylactic acid (PLA), which is polymerized from biosynthetic lactic acid, as a typical representative of natural materials, has become the most active biological materials in recent years because of its good performance and the application characteristics of both bioengineering materials and biomedical materials

1. Polylactic acid (PLA)

polylactic acid is a polymer synthesized by artificial chemistry from lactic acid produced by biological fermentation, but it still maintains good biocompatibility and biodegradability, has impermeability similar to polyester, and has gloss, clarity and processability similar to polystyrene, and provides heat sealability at a lower temperature than polyolefin. Melting processing technology can be used, Including spinning technology for processing. Therefore, PLA can be processed into various packaging materials, plastic profiles and films for agriculture and construction, as well as non-woven fabrics and polyester fibers for chemical and textile industries. The production energy consumption of PLA is only 20% - 50% of that of traditional petrochemical products, and the carbon dioxide produced is only 50% of that

in addition to being used as packaging materials, PLA can become one of the research hotspots in these drug packaging materials and tissue engineering materials. PLA can be made into non-toxic tissue engineering scaffold materials that can carry out cell attachment and growth. The porous structure for cell growth and transportation of nutrients can be formed inside the scaffold, and it can also provide appropriate mechanical strength and geometry for supporting and guiding cell growth. Its disadvantage is the lack of selective interaction with cells. PLA is widely used in biomedical materials. It can be used for medical sutures (no need to remove sutures), drug controlled release carriers (reduce the number and amount of administration), orthopedic internal fixation materials (avoid secondary surgery), tissue engineering stents, etc. At present, there are five kinds of P pictures sold in the international market source: DuPont La -

(1) (ecopla) products of cargilldow company in the United States. In 1998, a 3600t/year semi industrialized device was built, and the production capacity doubled at the end of the year. It is estimated that the plant in NE brasla can produce 7% in 2002 × 105T PLA. This figure can reach 1 in 2003 × 106t (its production capacity is 1.5 × 106t/year). Cargill Dow first cooperated with four Japanese companies (Pacific Dunlop, Sony, ntrpcomo and mitsdubishiplastics) that intend to use PLA as applied packaging materials, and then expanded to Europe and the United States (the above information is from Cargill Dow's homepage)

(2) LACEA products of Mitsui chemical company of Japan, with a production capacity of 500t/year

(3) lacty products of Shimadzu production Institute in Japan mainly produce polylactic acid films. The production capacity is 1000t/year

(4) CPLA Japan ink and chemical industry company has a production capacity of 1000t/year. In the next few years, the company will build thousands of tons of CPLA devices

(5) heplon chronopol products, 2000t/A, plans to build a world-class production plant. In terms of PLA as a plastic product, foreign chronopol companies have reduced the production cost of PLA from 80000 yuan/t-120000 yuan/T to 30000-40000 yuan/T; The total domestic production cost is at least 45000 yuan/T, slightly higher than that of the United States. The price of general plastics, such as polypropylene, is as low as 6200 yuan/T, which is only about 1/7 of the cost of PLA. To make polylactic acid widely used as packaging materials and disposable products, its price should be reduced to less than 20000 yuan/T in order to have a certain market acceptance. Therefore, accelerating the corresponding research and development has important social benefits. However, at present, the vast majority of the production, processing and Application Patents of PLA are still in the hands of some developed countries. Therefore, if we want to develop the PLA industry well, we must invest more in basic application research, in order to obtain our own independent intellectual property rights, so as to make PLA production better localized. In the future, the research on the biochemistry of synthetic biomaterials and the composite of various materials will be paid attention to

the annual production of plastics in the world is now 1.5 × 108t, of which 2 can be replaced by PLA at present × 105T (if there is enough production). As the price of petroleum products rises, the environmental performance advantages of PLA products are gradually reflected, and PLA will occupy more market share. According to the prediction of relevant Japanese experts, the annual demand for polylactic acid products in the world will reach 3 × 106t, which will greatly promote the development of polylactic acid. Therefore, further reducing the fermentation cost of lactic acid, improving the polymerization process of lactic acid and improving the application of PLA in tissue engineering will be the focus of PLA research

2. Polyhydroxy fatty acid ester (PHA)

a biopolymer material, polyhydroxy fatty acid ester (PHA), which has developed rapidly in recent 20 years, is an intracellular polyester synthesized by many microorganisms and a natural polymer biomaterial. PHA has become the most active research hotspot in the field of biomaterials in recent years because it has good biocompatibility, biodegradability and thermal processing properties of plastics, and can be used as biomedical materials and biodegradable packaging materials at the same time. PHA also has many high value-added properties, such as nonlinear optics, piezoelectricity, gas separation and so on

natural or synthetic biodegradable polymer materials often have high water vapor permeability, which is unfavorable in food preservation. PHA has good gas barrier, which makes it possible to be used in fresh-keeping packaging for a long time. Because the penetration of water vapor is an important indicator in fresh-keeping packaging, the performance of PHA can be completely compared with current pet, PP and other products. On the other hand, PHA also has good hydrolysis stability. When PHA is washed for 20 cycles with an automatic dishwasher at 75 ℃, the shape and molecular weight of the cup made of PHA have not changed, indicating that PHA can be well used in appliance production. In addition, compared with other polyolefins and polyaromatic polymers, PHA also has good UV stability. PHA can also be used as a source of biodegradable environmental solvents. For example, EHB (ethyl 3-hydroxybutyrate) is water active and has low volatility. It can be used as a solvent for cleaners, adhesives, dyes and inks. Because PHA brings together these excellent properties, it can be applied in a wide range of fields, such as packaging materials, bonding materials, spraying materials and clothing materials, appliance materials, electronic products, consumer durables, agricultural products, automation products, chemical media and solvents

(1) compared with PLA and other biological materials, PHA has diversified structures. The composition of PHA can be easily changed by changing bacteria, feed and fermentation process, and the performance diversification brought by the diversity of composition structure makes it have obvious advantages in application. According to the composition, PHA is divided into two categories: short chain PHA (monomer C3-C5) and short chain PHA

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