Category Archives: Science

Polymer Journal 4

In total we made 3 prototypes. Our end product is called Eco-Dough, and will be packaged in environmentally friendly paper bags lined with wax. You can purchase it for 20 Kuai per bag or it will be shipped to manufacturers in bulk.

Prototype 1:

3 tbs cornstarch

1 tbs water

Microwaved for a total of 40 seconds on medium heat

  • Very crumbly
  • Very cracked (after the crack test where we let it out to dry)
  • Not very bouncy
  • Dried extremely fast
  • Developed a hard ‘skin’ around the clay while it dried

One strength from this prototype is the hard skin proving that it will dry to be a strong material. All other observations are properties that are not desired in the final product. Since it was crumbly and had a fast dry time,  it would not allow the user to make their own toys successfully. 

Prototype 2:

2 tbs cornstarch

1 tbs guar gum

50 ml water

Microwaved for a total of 30 seconds on light heat

  • Squishy
  • Flexible
  • Holds its shape
  • Bouncy
  • Too sticky
  • Did not crack very much during crack test

The only limitation from this prototype was that it was too sticky. If the clay is too sticky, then molding toys with it will be extremely hard. All other properties such as its flexibility and its ability to hold its shape are all properties of polymer clay and is what we are looking for.

Prototype 3:

6 tbs cornstarch

2 tbs guar gum

40 ml water

Microwaved for a total of 40 seconds on light heat

  • Squishy
  • Soft
  • Flexible
  • Holds its shape
  • Dries hard and strong

Because of prototype 2’s  limit of the clay was too sticky, we decided to add less water so it would not be as sticky but microwaving it for less so it wouldn’t be too dry. The end product was exactly what we were looking for, a clay that had all properties of polymer clay but was 100% eco-friendly and safe. We have concluded that prototype is the best prototype out of all three.

Here is the table we used to record our data

Polymer Project 3

Our polymer idea is eco-friendly and child-safe polymer clay. We would want all the properties normal polymer clay has such as the ability to hold its shape, its flexibility, softness, and that it dries hard. Our plan was to take a basic dough recipe (cornstarch + water) but to alter it to fit the properties of polymer clay.

We first started out the basic clay recipe, but it was too hard and not moldable at all. We then decided to add some guar gum to give it an elasticity that is closer to polymer clay. We tried two prototypes one with 2 parts cornstarch 1 part guar gum and one with 1 part cornstarch 2 parts guar gum. Both were either too soft or too hard.

The process we went through was testing and revising until we got the perfect consistency.

Here is the final recipe:

6 tbs cornstarch

2 tbs guar gum

40 ml water

 

  1. Take cornstarch, guar gum and water. Mix
  2. Heat using microwave (light heat) for 30 seconds with 10 minute intervals
  3. Knead until clay

 

When you mix cornstarch, guar gum and water together it forms a frosting like consistency and the water gives the cornstarch and guar gum some room to move around so they can start forming long polymer chains. When you microwave the substance, the cornstarch/guar gum polymers will grab onto each other making them stick together- thus forming the clay.

A problem we encountered is that it cracks when it dries. We used different prototypes and compared them when they dried. The last prototype cracked the least and meets all our expectations.

Here is a picture of our second clay prototype when put through the ‘crack test’ (mentioned above)

Here are pictures of our final prototype

 

Citations:

Justice, Lisa. “Corny chemistry.” Corny chemistry – Explorit Science Center. 23 May 2019 <http://www.explorit.org/news/corny-chemistry>.

Polymer Journal 2

Our goal for the Polymer Project is to create a polymer clay that is 100% eco-friendly and has the properties of polymer clay (mold ability, softness,  flexible). Our target audience are kids who are looking forwards to using their imagination and making their own toy. This clay allows you to make your own toy and is also a toy itself.

Polymer clay is the widely known and used modeling clay. Unfortunately, it contains PVC and it is extremely harmful to you and the environment. According to CBC 90% of all toys are made with plastic. With our polymer clay (made of cornstarch, guar gum and water) it is 100% environment friendly and also 100% safe for little kids.

We use cornstarch and water to make the dough- the base. We added guar gum to give it a bouncy, stretchy and soft texture and to keep the clay from drying too fast.

 

Heres our second prototype for our eco-friendly clay

 

Citations:

“What’s So Bad About Vinyl Plastic (PVC)?” Eco, 24 Sept. 2013, www.eco-novice.com/2013/09/whats-so-bad-about-vinyl-plastic-pvc.html.

“’Wasted’: Greening the Plastics-Heavy Toy Industry | CBC Radio.” CBCnews, CBC/Radio Canada, 5 Jan. 2018, www.cbc.ca/radio/day6/episode-371-iran-nuclear-deal-plastic-toy-waste-kaepernick-bitcoin-bunkers-spotify-vs-composers-and-more-1.4470486/wasted-greening-the-plastics-heavy-toy-industry-1.4470526.

Polymer Journal 1

Polymers are molecules that are chemically bonded together to form a long, repeated chain. All polymers start with a base, called the backbone. There are also pendant groups that hang loose or connect chains together. A chemical bond is what holds the atom chains together. In class, we made slime using PVA glue and borax. When borax / laundry detergent is added to the PVA, it changes the position of molecules in a process called cross linking and forms chains- which is the slime.

Synthetic polymers are human-made polymers. Some examples are Nylon and Rubber, yet these are made from natural resources such as tree latex and petroleum oil. To make these natural resources into the polymers, polymerization (combining molecules), heating and spinning, and lastly manufacturing.

Citations:

Perkins, Sid. “Explainer: What Are Polymers?” Science News for Students, 13 Oct. 2017, www.sciencenewsforstudents.org/article/explainer-what-are-polymers.

“The Science Behind Slime.” Little Bins for Little Hands, 22 Apr. 2019, littlebinsforlittlehands.com/basic-slime-science-homemade-slime-for-kids/.

 

Here is a model of a polymer