cylindrical_specimen_synthesizing.pdf

1.Purpose:

The purpose of this protocol is to offer a guideline for synthesizing cylindrical specimens of SMPs, which are suitable for standard uniaxial compression experiments.

2. Materials and Equipment:

tert-Butyl Acrylate, Poly(ethylene glycol) Dimethacrylate, Di(ethylene glycol) Dimethacrylate, 2,2-Dimethoxy-2-Phenylacetophenone

Centrifuge Polypropylene Tubes (50ml), Tube Racks, Balance, Pipette, Pipet Tips, Transfer Pipets with Standard Bulb, Vortex Genie 2 Mixer, Weigh Boats, Spatula, Glass Tubes (Inner diameter 12mm), Rubber Stopper (diameter 12mm), Vacuum Oil, UV Oven, Incubator, Refrigerator, Laser Cutter

3.Steps:

(As an example, the following steps are for the synthesizing of 10 wt% specimens. For 20, 40 wt% specimens the procedure is the same but with different chemical ratios, refer to Table 1. The absolute amount of each chemical is subjected to change based on the number of specimens need to be synthesized.)

Step1: Put the polypropylene tube on the balance, and then zero the balance.

Step2: Transfer 1.24ml DEGDMA into the polypropylene tube using a pipette with

pipet tip. Measure the mass using the balance.

Step3: Change a new pipet tip. Transfer 2.84ml PEGDMA into the polypropylene tube using a pipette with pipet tip. Measure the mass using the balance. Make sure the mass ratio of DEGDMA: PEGDMA is 3:7.

Step4: Change a new pipet tip. Transfer 45.92ml tBA into the polypropylene tube using a pipette with pipet tip. Measure the mass using the balance. Make sure the mass ratio of DEGDMA: PEGDMA: tBA is 3:7:90.

Step5: Put a weigh boat on the balance. Zero the balance. Add the photoinitiator (2,2- Dimethoxy-2-Phenylacetophenone) to the weigh boat using a spatula until the mass of the photoinitiator is 0.1% of the mass of the polymer solution.

Step6: Add the photoinitiator to the polymer solution. Screw the cap on tightly. Put the tube on the mixer for 1-2 mins. Make sure the photoinitiator is fully dissolved.

Step7: Seal one end of the glass tube using a rubber stopper. Secure the sealing with vacuum oil. Make sure there is no leaking.

Step8: Inject the polymer solution into the glass tube using a transfer pipet with bulb. Seal the other end of the glass tube using a rubber stopper. Secure the sealing with vacuum oil. Make sure there is no leaking.

Step9: Put the sealed glass tube into the UV oven.

Step10: Turn on the UV oven. Expose the glass tube containing polymer solutions to UV light for 20 mins in total. For the first 10 mins, rotate the glass tube every 1 minute to get a uniform exposure to the UV light. For the next 10 mins, do this every 2 or 3 mins.

Step11: Turn off the UV oven. Transfer the glass tube into the incubator. Equilibrate at 70°C for 60-90 mins.

Step12: Cool down the specimen in a refrigerator. Separate the cylindrical polymer specimen from the glass tube. Cut the specimen into several short ones with desired length using a laser cutter.

Table1. Mass ratios and volume ratios of three chemicals for 10, 20 and 40 wt%