Characteristics and R&D of Environment-friendly Functional Materials (1)

Among the many materials in the forest, there are some materials with many special functions. These functions mainly include excellent chemical functions, thermal functions, electromagnetic functions, optical functions, mechanical functions, acoustic functions, and corresponding optical, electrical, magnetic, thermal, and mechanical energy. The conversion function, as well as biological functions and other special functions, are used in high-tech materials for non-structural purposes, including metals, metalloids, ceramics, organic polymers, and composite materials. It can be considered that functional materials are relatively advanced materials in modern materials. The “functionality” of functional materials is often the main feature of distinguishing materials from functional materials. In the recent decades, the development of functional materials has been strengthened. These conditions have attracted great attention from the scientific community at home and abroad and opened up new areas for the research and application of functional materials.

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: a polymer series, metal series, ceramic series.

Based on the functional properties of materials, materials can also be classified into functional materials such as mechanical properties, acoustics, thermal, electrical, magnetic, optical, chemical, biomedical, and nuclear functions.

Based on the technical field of materials 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 internal arrangement of the material, the material can be divided into crystalline and amorphous. According to the thermodynamic state of the material, the materials are divided into steady state and metastable state. According to the material size is divided into one-dimensional, two-dimensional. Three-dimensional material.

Functional materials have the following features.

1, with special features. For example: ultra-high strength, superplasticity, superconductivity, magnetism, luminescent properties, etc.; the preparation of functional materials is often closely related to new technologies, new processes, and it can be said that new technologies and new processes are powerful tools for the development of functional materials.

2. Faster replacement of functional materials, changeable styles, similar characteristics with other high-tech, rapid development of functional materials, and short development cycle.

3. The development of functional materials is closely related to the development of material theory and is closer than traditional materials. The preparation and production of traditional materials rely more on experience and craftsmanship. The development of new materials is more under the guidance of theories. In the research of functional materials, electronic materials used in computers, information, and biology will receive attention. The environmental coordination of materials will receive unprecedented attention, not only in the recycling of materials, but also in saving materials, reducing energy consumption, and protecting the environment. The design of packaging materials must meet the physical and chemical properties of the contents and have an effective protection function. For example, vegetables and fruits require air permeability and moisture permeability; frozen foods require materials with low temperature toughness; easily oxidized food packaging materials require gas barrier properties. The decrease in functionality causes the content to be commercial, which is undoubtedly the largest consumption of packaging and content resources and energy. It is also necessary to ensure the strength of the packaging material and the sealability of the packaging to prevent the phenomenon of “running, leaking, and floating” in the packaging process, transportation process, storage process, and use process, and cause environmental pollution.

Such as nano-functional composite materials in food packaging, researchers from the National Special Ultrafine Powder Engineering and Technology Research Center of Nanjing University of Science and Technology, will make nano-Tio2 and Sio2 hollow composite microspheres, placed in food packaging bags or boxes, can be With good anti-corrosion and preservation effects, the food preservation period can be extended by 1~2 times. The nano-composite cling film made of PVC/Tio2 is a good fresh-keeping material for fruits. For example, Chen Li et al. used SG_IV type PVC resin as a base material, added nano-Tio2 and 11 other functional materials to make a high-strength Tio2 nano-Fuji apple cling film. After identification, the longitudinal tensile strength increased by 36%. The oxygen permeability decreased by 18%, the moisture permeability decreased by 10%, and the Co2 permeability only changed by 1.5%. After a health inspection, the Fuji apple was stored in a 0. 03mmpvc small package and stored at 0C to 1C for 208 days, indicating no co2 damage. The flesh hardness reached 7.57kg/cm2, and the oxygen in the bag remained at 3.1% to 5.6%. Co21.7%~2.6%. From this point of view, the preservation effect of this nanocomposite material is very satisfactory.

There are also synthetic kraft papers, which are the latest research results of imitation paper film. It is a new type of packaging material with both functions and environmental protection. The performance of imitative paper (synthetic paper) is very unique. In addition to the characteristics of plain paper, it also has the advantages of plastic film, such as waterproof, printing composite effect, tensile strength, corrosion resistance, insect resistance, dimensional stability , It can have heat sealing properties, so it can reach a wider range of uses than ordinary paper. At present, the imitated paper film (synthetic paper) mainly has the following uses: food packaging, industrial product packaging, tire packaging, express envelopes, various packaging boxes , Advanced color printing, high-end books, maps, charts, pictorial, business cards, playing cards, advertising paper, recording paper, textbooks, ancient books, samples, calendars, greeting cards, paper hats, menu cards, advanced notebooks, various bags , medicines and cosmetics base materials, like paper, tracing paper, tourism promotional supplies and so on. With the deepening of the research on imitative paper (synthetic paper), the performance of imitative paper (synthetic paper) is improved, and its application field will be further expanded.

(to be continued)