Germany invents a new type of fresh plastic film

German scientists recently invented a plastic film “stained” with chlorophyll that prevents the rot of light from chlorophyll in green foods to cause food rot, thus greatly prolonging the preservation time of green foods.
According to reports, scientists at the Fraunhofer Institute of Processing and Packaging Technology in Germany “stained” plastic films with chlorophyll in a special way. After such processed films are used to package foods, they can effectively “intercept” food rots. The light thus greatly extends the food shelf life. The new method is not only easy and inexpensive. Most green foods contain large amounts of chlorophyll, and this pigment undergoes photooxidation under light irradiation, decomposing the energy in the food and leading to food rot. In order to extend the shelf life of foods, traditional packaging materials are either made of opaque packaging material or plastic and vacuum-treated to insulate the food from oxygen. The former can't make customers choose intuitively, while the latter is more complicated and the cost is relatively high.
Synchronous crystal transformation and corona polarization equipment is an important instrument for preparing polymer piezoelectric films. The piezoelectric strain constant of piezoelectric films prepared by it is much higher than that of piezoelectric films prepared by non-simultaneously stretched polarization equipment. The strain constant of the film. In particular, with the wide application of PVDF piezoelectric films, the development of such piezoelectric thin film special equipment has become a hot topic for people in the scientific and technological circles and the business community.
In order to adapt to the actual needs of domestic research and production of polymer piezoelectric films, in 1999, under the funding of the Chinese Academy of Sciences, Changchun Yinghua undertook the task of “simultaneous crystal-type conversion and corona polarization equipment”. They designed their own. A polymer film making machine and a synchronous stretching polarizing device: a polymer film forming machine composed of a transmission device, a charging device, a screw, a head, and a film-attaching machine, and a corona pole Tensile and corona polarization equipment consisting of a box, transmission, support device, and heating device. Simultaneously solved the key technical problems of crystallographic conversion and corona synchronization of the entire equipment, and successfully developed this equipment for synchronous crystal transformation and corona polarization. After related units used the equipment to prepare piezoelectric films, It is considered that the polarization performance is good, the voltage and temperature are adjustable, and the stretching ratio can be controlled. The PVDF piezoelectric strain constant can reach 20-34 PC/N, and the instrument is easy to use and has good performance.
According to reports, the piezoelectric thin film special equipment has the following characteristics: the use of speed difference and the ratio of the number of teeth to control the stretching ratio, while polarization, can be continuously prepared PVDF piezoelectric film; in the processing of PVDF piezoelectric film technology, shortened The processing time, reduced polarization temperature, industrialization is relatively easy to achieve; PVDF piezoelectric films prepared with this device have excellent piezoelectric properties. The successful development of this equipment has great economic and social benefits. It not only creates good conditions for the mass production of piezoelectric films in the future, but also provides the basis for technology and equipment for further industrialization.