Lab #8 - Polymers - Results and Discussion Poly(vinyl...

Info icon This preview shows pages 1–2. Sign up to view the full content.

View Full Document Right Arrow Icon
Results and Discussion: Poly (vinyl alcohol) or PVA is made by first polymerizing vinyl acetate then, the poly (vinyl acetate) is hydrolyzed in a basic solution which yields the acetate ion CH 3 CO 2 - and PVA. There are many –OH groups in PVA which causes it to form good hydrogen bonds, making PVA very soluble in water. It can also form good hydrogen bonds with other substances such as the borate ion, B(OH) 4 - . When B(OH) 4 - is added to an aqueous PVA solution , the ion cross links the PVA by forming hydrogen bonds. This creates a three dimensional network of polymer strands that are hydrogen-bonded to the borate ions and water molecules. This cross-linking can be removed by the addition of an acid and restored by the addition of a base. This experiment tested the effect cross- linking had on the viscosity, or the resistance of a liquid to flow, of the polymer solution. Part A - Cross-linking PVA First, the PVA solution was made by adding 2.045g PVA to 90°C tap water. The PVA was added very slowly with constant stirring. A clear gel-like solution was formed. The viscosity was tested here before any cross-linking occurred. A ball bearing was used to test the viscosity of the PVA solution. It was dropped in the solution and the time it took to fall was measured.
Image of page 1

Info icon This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
Image of page 2
This is the end of the preview. Sign up to access the rest of the document.

{[ snackBarMessage ]}

What students are saying

  • Left Quote Icon

    As a current student on this bumpy collegiate pathway, I stumbled upon Course Hero, where I can find study resources for nearly all my courses, get online help from tutors 24/7, and even share my old projects, papers, and lecture notes with other students.

    Student Picture

    Kiran Temple University Fox School of Business ‘17, Course Hero Intern

  • Left Quote Icon

    I cannot even describe how much Course Hero helped me this summer. It’s truly become something I can always rely on and help me. In the end, I was not only able to survive summer classes, but I was able to thrive thanks to Course Hero.

    Student Picture

    Dana University of Pennsylvania ‘17, Course Hero Intern

  • Left Quote Icon

    The ability to access any university’s resources through Course Hero proved invaluable in my case. I was behind on Tulane coursework and actually used UCLA’s materials to help me move forward and get everything together on time.

    Student Picture

    Jill Tulane University ‘16, Course Hero Intern