Functional materials in the hottest Packaging Engi

Functional materials in Packaging Engineering (I)

in Lin Yiduo's measures to promote the development of domestic instruments and ceramic like bright surfers, which is shortened with the foreign technical level, Lin Zong's materials have many special functions, which mainly include excellent chemical function, thermal function, electromagnetic function, optical function, mechanical function, acoustic function and corresponding optical, electrical, magnetic, thermal And the conversion function of mechanical energy, biological function and other special functions, which are used for high-tech materials for non structural purposes, including metals, metalloids, ceramics, organic polymers, composites, etc. It can be considered that functional materials are more advanced materials in modern materials, and the "functionality" of functional materials is often the main feature to distinguish whether materials belong to functional materials. In recent decades of the rapid development of high technology, the development of functional materials has been strengthened. These situations have attracted great attention from the domestic surgical technology community, opening up a new field of functional materials research and application

according to the physical properties of materials, functional materials can be divided into the following categories. 1. Metal functional materials: such as metal materials with magnetic function, thermal function, mechanical function and chemical function; 2. Inorganic non-metallic functional materials: semiconductor magnetic functional materials, glass, ceramics, etc; 3. Organic functional materials: all kinds of organic polymer functional materials, such as conductive polymer materials, magnetic polymer materials; 4. Composite functional materials: polymer series, metal series, ceramic series, etc

based on the functional properties of materials, materials can also be divided into: mechanical properties, acoustic, thermal, electrical, magnetic, optical, chemical, biomedical, nuclear and other functional materials

based on the technical field of material services, functional materials can be divided into: electronic materials, optical materials, telecommunications materials, instrumentation materials, sensor materials, computer materials, electrical materials, reactor materials, solar energy materials, hydrogen storage materials, biomedical materials, environmental functional materials, etc. In addition, according to the arrangement of atoms in the material, the material can be divided into crystalline and amorphous states. According to the thermodynamic state of materials, materials are divided into steady state and metastable state. It can be divided into one-dimensional and two-dimensional according to the size of the material. Three dimensional materials

functional materials have the following characteristics: using the wind path switching mode to guide the temperature into the test area. 1. It has special functions. For example, ultra-high strength, superplasticity, superconductivity, magnetism, luminescence characteristics, etc; The preparation of functional materials is often closely related to new technologies, new processes, and so on. It can be said that new technologies and new processes are powerful tools for the development of functional materials. 3. Functional materials have the characteristics of fast generation and changeable styles, which are similar to other high-tech. the research and development speed of functional materials is fast and the development cycle is short. 4. The development of functional materials is closely related to the development of material theory, and more closely than traditional materials. The preparation and production of traditional materials rely more on experience and technology, while the development of new materials is more under the guidance of theory. In the research of functional materials, electronic materials used in computer, information and biology will be paid attention to. The environmental coordination of materials will receive unprecedented attention, not only in the recycling research of materials, but also in saving materials, reducing energy consumption and protecting the environment. The design of packaging materials should meet the physical and chemical properties of the contents and have effective protection function. For example, vegetables and fruits require materials to have air permeability and moisture permeability; Frozen food requires materials with toughness at low temperature; Gas barrier is required for easily oxidized food packaging materials. The reduction of functionality causes the content to be commercial, which is undoubtedly the largest consumption of resources and energy of packaging and content. It is also necessary to ensure the strength of packaging materials and the sealing of packaging, and prevent the products from "running, leaking, floating" and other phenomena during the packaging process, transportation process, storage process and use process, resulting in environmental pollution

for example, in food packaging, researchers from the national special ultra-fine powder engineering technology research center of Nanjing University of science and technology made hollow composite microspheres of nano-TiO2 and SiO2 and placed them in food packaging bags or boxes, which can play a good role in anti-corrosion and fresh-keeping, and the fresh-keeping period of food can be extended by 1~2 times. The nanocomposite fresh-keeping film made of pvc/tio2 is a good fresh-keeping material for fruits. For example, Chen Li et al_ The high-strength TiO2 nano Fuji Apple fresh-keeping film is made of type IV PVC resin as the base material, adding nano TiO2 and 11 other functional materials. After identification, the longitudinal tensile strength is increased by 36%, the oxygen permeability is reduced by 18%, the moisture permeability is reduced by 10%, and the CO2 permeability is only changed by 1. 5%。 After sanitary inspection, Fuji Apple was used as 0. The 03mm PVC small package was sealed and stored at 0c~1c for 208 days, which showed that there was no CO2 damage, and the pulp hardness reached 7. 57kg/cm2, the oxygen in the bag is still 3.1% - 5.6%, co21.7% - 2.6% From this point of view, the preservation effect of this nanocomposite is very ideal

it is estimated that the average growth rate of "1025" is about 10%, and synthetic kraft paper is the latest research achievement of paper imitation film, which is a new packaging material with both function and environmental protection. The performance of imitation paper film (synthetic paper) is very unique. In addition to the characteristics of ordinary paper, it also has the advantages of plastic film, such as waterproof, good printing compound effect, high tensile strength, corrosion resistance, moth resistance, stable size, heat sealing and so on. Therefore, it can be used more widely than ordinary paper. At present, imitation paper film (synthetic paper) mainly has the following uses: food packaging, industrial product packaging, tire packaging Express envelopes, all kinds of packaging boxes, high-grade chromatic printing, high-grade books, maps, charts, pictorials, business cards, playing cards, advertising paper, recording paper, textbooks, ancient books, samples, calendars, greeting cards, paper hats, menu cards, high-grade notebooks, all kinds of packaging bags, drugs and cosmetics substrates, such as paper, tracing drawings, tourism promotional supplies, etc. With the further research on the imitation paper film (synthetic paper), the performance of the imitation paper film (synthetic paper) will be improved, and its application field will be further expanded

as we all know, kraft paper will cause great environmental pollution in the process of use, and it is difficult to recycle when mixed with non-homogeneous products.. At present, the Yellow imitation paper film (synthetic paper) is used to replace kraft paper. Because the synthetic kraft paper (imitation paper film) and the woven bag are made of the same material (both PP materials), it can be easily recycled and reused together, and has better environmental protection performance. The woven bag made by this method not only has elegant and high-grade appearance, strong visual effect, improves the grade of products, can bring more profits to merchants, but also has good shading effect. At the same time, synthetic kraft paper has the functions of waterproof, insect proof and reinforcement, which strengthens the common functions of traditional woven bags

with the development of industry and the needs of consumption, people hope that the storage life of future food industrial products, especially health food, will be longer, which requires the development of composite packaging towards serialization, multi-function, high performance, special functions and so on

due to the development of supermarkets and fast food stores, a new concept of HMR has emerged and prevailed abroad in recent years, and the HMR market has developed rapidly. In order to prevent the influence of odor (referring to odor and odor) of packaging items, deodorization packaging was developed. At present, there are more than 40 kinds of deodorization packaging materials, which are mainly divided into three types: Class A is a chemical deodorization type, which can remove the odor or peculiar smell of nitrogen compounds and sulfur compounds plus ammonia, dimethylamine, trimethylamine, hydrogen sulfide, etc. Class B belongs to physical type, which is mainly used to remove odor or peculiar smell such as hydrogen sulfide and carboxylic acid, and is characterized by good deodorization effect on high concentration hydrogen sulfide. Class C materials are mixed deodorization type. It is mainly made of activated carbon deodorant. The characteristics of this kind of material are low concentration and good deodorization. Deodorizing packaging paper film can also play a deodorizing and fresh-keeping effect when used in food packaging. General deodorization packaging is mainly used for the packaging of food with special smell or peculiar smell, as well as agricultural products and aquatic products