In the laboratory exercise "Preperation and Properties of Polymers", polyvinyl alcohol is dissolved in water and then reacted with borax (Na2B4O7·10H2O) in water. Which of the following are expected results of this reaction?

True or False?
1. Polyvinyl alcohol became graft copolymer with pendant borate groups.
2. Polymer crosslinks into a rock-solid mass.
3. Solution changes color (without a coloring agent such as a dye or food color.
4. Hydrogen-bonding between the polymer and boron hydroxide results in a slime.
5. Solution expands in volume dramatically.
6. Polymer forms 2-dimensional polymer sheets or films, similar to plastic wrap.
7. Solution becomes much more viscous (thicker).
8. Polymer disassociated into component monomers upon addition of boron.

To determine the expected results of the reaction between polyvinyl alcohol and borax, we can analyze the properties and behavior of these substances.

1. Polyvinyl alcohol became graft copolymer with pendant borate groups. - True: When polyvinyl alcohol reacts with borax, it forms a graft copolymer. Borate groups from borax become attached to the polymer chains of polyvinyl alcohol.

2. Polymer crosslinks into a rock-solid mass. - False: The reaction between polyvinyl alcohol and borax does not result in a rock-solid mass. Instead, it forms a gel-like substance.

3. Solution changes color (without a coloring agent such as a dye or food color). - False: The reaction of polyvinyl alcohol with borax does not cause a color change in the solution.

4. Hydrogen-bonding between the polymer and boron hydroxide results in a slime. - True: When polyvinyl alcohol reacts with borax, the hydrogen bonding between the polymer and boron hydroxide leads to the formation of a slimy substance. The slime is commonly referred to as "oobleck."

5. Solution expands in volume dramatically. - False: The reaction between polyvinyl alcohol and borax does not cause a dramatic expansion in volume.

6. Polymer forms 2-dimensional polymer sheets or films, similar to plastic wrap. - False: The reaction between polyvinyl alcohol and borax does not result in the formation of 2-dimensional polymer sheets or films.

7. Solution becomes much more viscous (thicker). - True: The addition of borax to the polyvinyl alcohol solution increases its viscosity, making it thicker.

8. Polymer dissociates into component monomers upon the addition of boron. - False: The reaction between polyvinyl alcohol and borax does not cause the polymer to dissociate into its component monomers.

In summary:
- True: 1, 4, 7
- False: 2, 3, 5, 6, 8