Step 1: Heat treatment

to make sure that all the solvent is evaporated from the specimen. Whichever state you want the specimen in after curing, it is safer to perform the heat treatment before any curing. It also helps making sure that you are not curing a physically aged state after a long storage.

  1. Put your specimen overnight in the incubator at 70C.
  2. Follow by one hour at 100C in the oven to put the specimen in a full isotropic state.
  3. From this point on, make sure the specimen is not stretched, or bent too much.
  4. Finally let the specimen cool at room temperature for at least 20 minutes on a flat and clean surface.

Step 2: Choice of cure state You need to know whether you want a polydomain or a monodomain specimen.

EITHER

Step 3: Photopolymerization in the polydomain state

The specimens contain an excess of acrylate molecules that react to UV light and form chemical bridges between molecules. The goal of this step is to make the excess acrylate react.

  1. Place the polydomain specimen on a clean flat surface.
  2. Take the UV lamp (far right upper cabinet), remove the protection on the bulb, plug it in.
  3. Position the UV lamp above it using chemistry poles, wood, books, whatever makes it stable.
  4. Prepare a timer
  5. <fc #ff0000>Put goggles on</fc>
  6. Turn on the UV lamp and make sure it is on WITHOUT LOOKING DIRECTLY AT IT! If the lamp is not on, there is sometimes a bad contact at the base of the lamp, giggling the wires might do the trick.
  7. Time the cure, 12 minutes should be enough, leaving it more will not damage the material but will heat it. Do not leave the lamp on more than 20-30 minutes.

OR

Step 3: Photopolymerization in the monodomain state

The specimens contain an excess of acrylate molecules that react to UV light and form chemical bridges between molecules.The goal of this step is to make the excess acrylate react on the monodomain state so that the oriented state is fixed. When you remove the load, the specimen will stay elongated and transparent.

  1. Measure the section of the specimen
  2. Place the polydomain specimen in the tensile machine, the same way you would to do a simple tensile test. Fill out the dimensions in the software. Make sure the distance between the grips is close the gage length of the specimen and that you are as precise asa possible on the gage length.
  3. Take the UV lamp (far right upper cabinet), remove the protection on the bulb, plug it in.
  4. Position the UV lamp on a chemistry pole placed on the ladder in front of the tensile machine, use whatever you find makes it stable and facing directly the specimen in between the grips. CAREFUL the specimen will be stretched at least a hundred percent so make the UV lamp aim a little bit higher than the current position of the specimen.
  5. Prepare a method in TestWorks stretching the specimen to 100% relatively slowly (⇐ to 1%/s) and holding the stretch for 20 minutes at least. Make sure you do not put return to gage length at the end.
  6. Prepare a timer on your phone or computer
  7. Start the mechanical test
  8. Watch the specimen to make sure it does not slip out of the grips or sideways
  9. <fc #ff0000>MOST IMPORTANT STAGE</fc> when the strain reaches 100% and is constant, check that the specimen is fully transparent (Fully monodomain) along the gage length. If it is, go to the next step. If not, stop the test, the strain will still hold but the load won't be recorded anymore. If necessary, increase slowly the strain using the manual command until the specimen is fully transparent. Write down the current extension and compute the new cure strain.
  10. <fc #ff0000>Put goggles on</fc>
  11. Turn on the UV lamp and make sure it is on WITHOUT LOOKING DIRECTLY AT IT! If the lamp is not on, there is sometimes a bad contact at the base of the lamp, giggling the wires might do the trick.
  12. Time the cure, 12 minutes should be enough, leaving it more will not damage the material but will heat it. Do not leave the lamp on more than 20-30 minutes.

Step 4: Heat treatment

  1. Place the specimen 20 minutes at 120C to bring it to the isotropic state
  2. Let the specimen cool at room temperature for at least 15 minutes before any further testing.
  3. If you cured in the polydomain, the specimen should exactly the same as when you started (I know, disappointing).
  4. If you cured in the monodomain state, the specimen should be almost perfectly transparent at room temperature. If you see opaque (white) zones appearing or the whole specimen becoming opaque, the curing failed. In that case, take a new specimen and start all over again.