Hardness Determinations of Various Polymer Coatings


TEACHER NOTES


Objectives: Students will

Applicable Science Concepts:

Supplies:


Safety:
Manufacturers provide instructions for the use of their products, and these instructions should be followed completely. Protective gloves and lab coats should be used when preparing and handling the glass slides with coatings, and safety glasses should be used at ALL times.

Activity:

Taken from the ASTM Standard Test Method for Film Hardness by Pencil Test: ASTM D 3363 - 74 (1989) http://www.astm.org/cgi-bin/SoftCart.exe/BOOKSTORE/COMPS/CONTENTS/71.html?L+mystore+mhth9641.


Preparation:


Investigation Procedures
:


Report:


The one/two endpoints as follows:


Conclusions:
Have groups of students share their data with other groups by putting their data either on the board or on an overhead. Students should discuss why hardness is important. Where would you use softer or harder coatings? Why? They can then compare the results of the hardness test to other physical characteristics they have already observed.


OUR TEST RESULTS (Scratch Hardness):

A: Armorall Car Wax – none E: Epoxy – F
B: 100% Acrylic Latex – HB F: Krylon Spray Enamel – F
C: Oil Based High Gloss Enamel – none G: Kilz Spray – none
D: Krylon Fusion – none H: Kilz in a Can – none

 

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