Making cakes, Hue girls accidentally discovered materials that can replace nylon

In an unintentionally discovered filter powder capable of creating a thin film of tensile strength, the two Hue girls immediately thought of using thin-rolled starch to film and then forming a bag.

They are 'Antimicrobial biological bags capable of decomposing and replacing plastic bags' by two students Nguyen Cam Binh Minh (grade 12) and Nguyen Cam Kieu Khanh (grade 11, Hue National High School for Education).

Antibacterial biological bag

Binh Minh and Kieu Thanh said, according to preliminary statistics of the Ministry of Natural Resources and Environment, an average daily consumer has to use at least one plastic bag. So with a population of more than 90 million people, our country consumes more than 90 million plastic bags a day and this number is increasing according to population growth.

In parallel with that, the amount of waste also increased constantly. This is a great challenge for the environment, because it takes a very long time for these plastic bags to be biodegradable, maybe 500 years or longer.

The existence of nylon in the environment will seriously affect the soil and water, because the plastic bags mixed with the soil will prevent oxygen from passing through the soil, causing soil erosion, making the soil unable to retain water and nutrients. , thereby making crops slow to grow.

Biological bags are synthesized at the rate of 20/70/30 Cassava crystals / PVA / nano Ag.(Photo: Nhat Tuan).

Binh Minh shared: 'More seriously, the soil and water environment polluted by plastic bags will directly and indirectly affect human health. In fact, many types of plastic bags made from pure petroleum when absorbed into the water will penetrate into the human body causing dysfunction and birth defects in young children. From the above fact, we have developed an antibacterial biological bag capable of decomposing plastic bags'.

Materials for manufacturing include: 100 ppm silver nano solution, Polyvinyl anlcol (PVA) pure powder, cassava starch and 99% glycerol.

'About a year ago, while making filter cake, I accidentally discovered filtered powder that was able to create a thin film of tensile strength. I immediately thought of using thin-rolled starch to film and then forming a bag . After that, I consulted Mr. Le Dai Vuong and was consulted by the teacher, contacting the lab to implement the idea ', Kieu Khanh added.

They are studying in the laboratory.(Photo: Nhat Tuan).

The substances contained in the nano silver solution create stability for nano silver and enhance the antibacterial properties of the solution. The cassava starch has the ability to create thin bags by itself and when mixed with other bagging materials and has the ability to quickly biodegrade in the natural environment.

To create the bag, the starch particles spread out and rearrange and interact directly with each other through hydrogen bonding and indirectly through water molecules, PVA has the ability to create bags, PVA bags with good tensile strength.

The combination of PVA and starch will create a product that improves the properties of materials to create bags. In addition, I also use essential additives such as glycerol in the fabrication of nano-silver and cassava starch to increase the processing capacity of starch.

By early 2017, the product was relatively complete. However, the product still has many shortcomings about aesthetics and now has basically perfected with beautiful design, high durability.

Antimicrobial biological bag capable of decomposing plastic bags

Binh Minh said, using bio-bags with antibacterial ability to pack vegetables to replace partially PE, PVC, and PP bags of high quality food packages.Biological bags are capable of decomposing instead of plastic bags and food -grade plastic bags to minimize the problem of plastic bags.

'Comparison of breaking tensile strength of plasticizer, glycerol bonding agent, showing biological bag tensile strength made from cassava starch at the rate of 10/80/30, 20/70/30 with price Treatment is nearly equal to the breaking strength of plasticizers, bonding agents. Thus, bio-manufactured bags at these rates are capable of being used to produce packaging , 'Binh Minh said.

Over the course of the experiment, the bags have the ability to absorb moisture increase over time. Along with that, the children determine the bag thickness is 0.038mm. The test results of the antibacterial activity of biological bags by the antibacterial ring method with two bacteria E.Coli and Salmonela proves that the bag has good antibacterial activity.

In addition, they also investigated the biodegradability of the bag by burying in soil environment by monitoring the weight loss of the bag. Accordingly, the bag's digestion time in soil environment decreases day by day and does not affect the environment.

Initial product of the test process on tomatoes.(Photo: NVCC).

They also tested the application of bags to preserve tomatoes. The results showed that the rate of evapotranspiration of the fruit has no biological bag faster than the fruit of bio-bag storage. Since then, it is known that this bio-bag has the ability to extend the shelf life and shelf life of food.

In order to better see the storage capacity of the bag, they should observe the tomato for 20 days. Specifically, tomatoes do not have biological bags with more wrinkled surfaces, fruit sizes are much smaller than those of bio-bagged tomatoes, softer than tomatoes with biological bags and there is a lot of damage. more tomatoes have biological bags.

After 20 days, two tomato fruits give different results.(Photo: NVCC).

According to Kieu Khanh: 'Products created are similar to plastic bags but are of better quality, have antimicrobial ability, cost of production and are equal or cheaper than current plastic bags. In addition, the product is biodegradable, not harmful to the environment. The application of antibacterial bio-bags in the export of fruits and food of Vietnam is a right choice for food to be fresh and delicious. '

At an average cost of about VND 400 per bag, products that are transferred technology will create environmentally friendly products and human health.

Sharing about the difficulties, they said, because they are still students, it is difficult to balance learning and working in the lab. In addition, they take a lot of time to balance the materials that make up the product, to achieve better tensile strength and to be more beautiful outside.

Recently, the product has won the first prize in the biochemistry field of the Thua Thien Hue province's Science and Technology Contest in 2017, the first prize in the Thua Thien Hue Youth and Children Innovation Contest. Thien Hue in 2017.

Binh Minh (third from left to right) and Kieu Khanh (next to Minh) received the prize in the Thua Thien Hue Youth and Children's Creative Contest in 2017. (Photo: Nhat Tuan).

In the near future, the product will be taken to the National Youth and Children's Creative Competition and they want to develop the topic by testing many other materials and looking forward to putting products into production lines to bring come closer to consumers.

Talking to Discovery Magazine, Mr. Le Dai Vuong (instructor) said that he appreciated the working spirit of Minh and Khanh's two children, they actively sought topics and could express their ideas. Good idea and passion for science.

'Biological bags are capable of decomposing for 2 months, with safety and durability, in the composition of nano-silver combination, so they are antibacterial. Products that can be kept dry and wet are not preserved, so in the coming time, the two children will overcome this limitation, ' said Dai Vuong.