(1) Functional composite materials.
At present, many kinds of functional composites mentioned above have been applied, but from the perspective of development, they are far from enough. Functional composites cover a wide range of applications. There are conductive, superconductive, insulating, absorbing (electromagnetic wave), semi-conductive, shielding or transmitting electromagnetic wave, piezoelectric and electrostrictive in electrical function, permanent magnet, soft magnetism, magnetic shielding and magnetostriction in magnetic function, light transmission, selective filtering, photochromism, photoluminescence, anti-laser, X-ray shielding and X-ray transmission in optical function, sound absorption, soft magnetism, magnetic shielding and magnetostriction in acoustic function. Sonar, anti-sonar, etc. In terms of thermal function, there are heat conduction, thermal insulation and heat protection, ablation resistance, flame retardant, thermal radiation, etc. In terms of mechanical function, there are damping, vibration reduction, self-lubrication, wear resistance, sealing, bullet-proof armor, etc. In terms of chemical function, there are selective adsorption and separation, corrosion resistance, etc., and others are not listed. Among the above functions, composite materials can play an important role in logistics packaging as main materials or auxiliary materials.
(2) Multifunctional composite materials.
Composite materials have the characteristics of multi-component, so they will inevitably develop into multi-functional composite materials. Firstly, a composite material with both function and structure has been formed, which has been proved in practical application. For example, U.S. military aircraft has self-preserving stealth function, that is, the application of electromagnetic wave absorbing functional composite material on the aircraft skin to avoid radar tracking, and this composite material is a high-performance structural composite material. At present, a multi-functional composite material which can absorb electromagnetic wave, infrared ray and be used as a structure is being developed. It can be said that the development towards multi-function is an inevitable trend to give full play to the advantages of composite materials. It also opens up broad prospects for the manufacture of special-purpose packaging.
(3) Smart composite materials.
Human beings have been expecting materials to have the ability to perceive external effects and to respond appropriately. At present, the sensing functional material and the material with executive function have been compounded together through a certain matrix, and connected with the external information processing system to transmit the information given by the sensor to the executive material so as to produce corresponding actions, thus constituting the smart composite material and its system. It can sense changes in the external environment and respond actively. Its function can be manifested in self-diagnosis, self-adaptation and self-repair. Only from the packaging aspect, it is predicted that smart composite materials will play a great role in the quality change of inner packaging commodities, damage and pollution during storage and transportation.
(4) Intelligent composite materials.
Intelligent composite materials are the highest form of functional materials. In fact, it is the development of self-decision-making ability on the basis of sensitive composite materials. It relies on the artificial intelligence system added in the external information processing system to analyze information, give decision-making, command and execution materials to make optimal choices. In this way, higher requirements are put forward for the sensitivity, accuracy and response speed of the sensing part and the executing part of the material, and a good blueprint for the future of packaging is also presented.
