Since the invention of plastic bags, and in a bid to improve the ways we package items, our environments have continued to suffer from the adverse effect of plastic materials carelessly dumped on the streets.
Mainly made from a derivative of crude oil, plastic bags may take ten to hundreds of years before they begin to break down. This automatically leads to land pollution. And if this is avoided by burning the plastic bags, it leads to air pollution.
Among the several ways targeted at mitigating the effect of plastic bags in our environment, bio-degradable bags have come to stay. They are made from plant products such as cornflour (corn starch) and wheat.
They’re a better alternative to plastic bags because of their ability to degrade even though they may take time (about three to six months). Also, they must be subjected to micro-organisms, humidity, sunlight, and oxygen.
The breaking down process of bio-degradable bags is relatively safe and biological.
Biodegradable Plastics
Biodegradable plastics are usually cellulose-based plastics, lignin-based plastics, natural fibers, reinforcement plastics, soy-based plastics, bacteria-based plastics, or starch-based plastics (which will be part of our case study in this article).
They are mainly classified into two types:
Hydro-biodegradable Plastics
During the degradation process, they may give off methane. They’re made from natural sources such as sugar cane, wheat, and corn. And they degrade faster than the oxo-biodegradable plastics.
Oxo-biodegradable plastics
In addition to their ability to compost, they can be recycled. They’re made by adding small amounts of fatty acid compounds of some transition metals to traditional plastics.
Both types of biodegradable plastics undergo chemical (oxidation and hydrolysis) and biological processes. They both give off carbon (iv) oxide as they degrade.
Conditions for Degradation of Biodegradable Bags
It’s not enough to just know the manufacturing process of biodegradable bags. Sound knowledge of the degradable process is also necessary, especially as there have been a lot of misconceptions about its degradability.
The term “biodegradable” doesn’t imply an automatic degradation of a biodegradable material once discarded. Some conditions must be met.
Heat
For degradation to take place, the material must be subjected to a heat of about 50 degrees Celsius. Sunlight must also be sufficient enough to trigger the degradation process. All these imply that if the bags are dumped in a water body, as is the norm with traditional plastics, they may still not degrade.
Oxygen
Biodegradable bags require oxygen for a complete breakdown of their molecules. If the oxygen present is not sufficient, methane may be produced, which is very harmful to the environment. Sadly, this is the case with most biodegradable bags dumped in landfills. This may make the bags no different from the traditional plastic bags.
Soil Organism
The main materials used in making biodegradable bags are natural materials that can be “eaten up” by microorganisms. Without the presence of microorganisms, degradation won’t be possible.
Characteristics of Biodegradable Bags
Just like any other material used for packaging food, biodegradable bags are ideal materials used in the food processing industry. They’re air and watertight, and resist bacteria. They are heat resistant, flexible, durable, and have a hard and crinkly texture.
This article will give you an insight on how to prepare biodegradable bags using two methods: corn starch and vinegar, and gelatin or agar.
Process of Making a Biodegradable Bag (Using the Corn Starch and Vinegar Method)
Ingredients Needed
Biodegradable bags can be made commercially or domestically. Ingredients necessary for this method include:
- 10ml of distilled water
- 1.5g of corn starch
- 1ml of white vinegar
- 0.5 – 1.5g of glycerol (also called glycerin)
- 1 – 2 drops of food coloring (optional)
Note: Glucose and sucrose can be used as a plasticizer in place of glycerol. Ordinary table salt can also be used as a substitute for vinegar.
Tools necessary for this production include
- Spatula
- Container
- Foil or parchment paper
- Sauce Pan
- Heat source (e.g. stove)
Procedure to Make Your Biodegradable Bag
- Step 1: Mix the corn starch and water in the container and stir with the spatula until it dissolves
- Step 2: Proceed to add the glycerol and vinegar, and mix properly. If you’re using the substitutes for vinegar and glycerol, be sure to inquire about the right measurements that will be perfect
- Step 3: Pour the mixture into the saucepan and heat. Turn the heat low and stir while it heats
- Step 4: When the mixture becomes thick and is free of lumps, remove it from the heat. You may add one or two drops of food coloring at this stage
- Step 5: Pour the mixture on a foil parchment or foil paper and leave the dough to cool
- Step 6: When the dough gets cool, you can then use your hand to shape it into a bag. The dough doesn’t have to be completely cold, otherwise, you won’t be able to shape it
- Step 7: Leave the bag for 2 – 3 days to dry properly
Process of Making a Biodegradable Bag (Using Gelatin or Agar)
Gelatin is a protein made from animal products. It’s made by the partial hydrolysis of collagen extracted from the skin and bones of animals. On the other hand, Agar is a gelatinous substance gotten from seaweed and usually processed into powders.
Ingredients Needed
- 12g of Gelatin or agar powder
- 3g of Glycerol
- 60ml of hot water
- Food coloring (optional)
Tools necessary for this procedure include
- Spatula
- Container
- Foil or parchment paper
- Sauce Pan
- Heat source (e.g. stove)
Procedure to Make Your Biodegradable Bag
- Step 1: Mix all the ingredients mentioned above into a fine mixture. You may beat the mixture to ensure that there are no lumps in it
- Step 2: Pour the mixture into a saucepan and heat in medium heat. At this stage, you may choose to add your color
- Step 3: Heat the mixture until it begins to froth, or when your candy thermometer indicates that it has reached a temperature of 95 degrees Celsius. As you heat, make sure you stir
- Step 4: Remove any excessive froth, then pour the mixture on a surface covered by foil or parchment paper
- Step 5: When it has cooled a little, you can mold the plastic into any shape you desire. You can also use a mold to determine the shape of your bag. Before you pour the hot mixture into the mold, coat the mold with a non-stick spray
- Step 6: Leave the molded plastic for two days to dry. To quicken the process, use a blow dryer
Safety Guides When Making Your Biodegradable Bag
Wear Protective Shields
In the process of stirring the mixture on heat, there could be some spills or splashes that may come in contact with your skin and cause it to scald. Make sure to put on gloves and aprons as you work.
Allow Proper Ventilation
It’s never advisable to work in an air-tight room. Smell and fumes from the heated mixture may trigger respiratory issues. If you have an already existing respiratory challenge, it’s best to carry out the process in the presence of another adult who might intervene if there happens to be an emergency.
Keep the Heat Low
When making your bag, it’s best to keep the heat source low. The process doesn’t require much heat.
Do it Under Close Supervision
If you’re inexperienced, underaged, or feel jittery about the process, you’re better off being under the supervision of someone more experienced than you. Fire incidents may arise, confusion may come up, and panic may even set in when things begin to turn out the way you don’t expect. Your supervisor will be there to help you.
Shop for Quality Ingredients
It’s best to visit a reliable mall around you to shop for your ingredients. To achieve your desired result, you need only original and natural materials. Using adulterated ingredients may be hazardous.
Keep Children Out of Reach
You must send children away and prevent them from coming too close. The smell, fume, and heated mixture may pose a serious health hazard for any child around. Even after you’re done with the process, it’s best to keep the newly made bag out of children’s reach. It may lead to suffocation.
Conclusion
Making a biodegradable bag can be fun, exciting, adventurous, and dangerous. However, by equipping yourself with the information contained in this article, you’re set to try out a homemade biodegradable bag. You may choose to study the process professionally after your first trial, then begin an industrial production.
