Casting Plastic Films:

1. PVC and plasticizer weight-ratios were combined in separate sterilized vials, using the table shown below.

2. 5 mL of dichloromethane solvent was added to each vial.

Sample vials
(click for enlarged)

3. Teflon paper was cut into 2.4 cm by 2.4 cm squares and one square was placed onto each microscope slide.

Sample slides
(click for enlarged)

4. To cast plastic films, pipettes were used to drop 1 mL of each solution onto the Teflon paper covered slide. 3 films were cast for each solution.
5. The slides were heated for fifteen minutes in a 60º oven to evaporate the dichloromethane solvent.
6. Forceps were used to peel the plastic films off the Teflon paper.

Pipettes used in the experiment
(click for enlarged)

Synthesis of Epoxidized Carthamus tinctorius Oil (ECTO):

Epoxidation was done via a chemo-enzymatic reaction with Novozym 435, a lipase. 7 mL of Carthamus tinctorius oil, 25 mL of toluene, and 0.75 g of Novozym 435 were mixed at constant agitation of 260 rpm with a stirrer at room temperature for 24 hours. 15 mL of hydrogen peroxide was injected into the flask over the same period of time via a syringe-pump. After agitation, a filtering funnel was used to separate the two distinct phases. The hydrophilic-toluene phase that contained the enzyme was removed, leaving the hydrophobic ECTO. Any remaining toluene solvent was evaporated by means of a rotary evaporator at 80ºC. Aliquots were examined by High Performance Liquid Chromatography to determine the extent of epoxidation. The percentage of epoxidized double bonds (EDB%) was calculated according to the following, where [Me], [De] and [L] are the respective molar concentrations of monoepoxyoctadecenoic acid, diepoxydecanoic acid and linoleic acid.

EDB % = ([Me]+2[De]) / (2[L]+2[Me]+2[De]) x 100

Release Behavior of DEHP:

PVC films were immersed in 1 mL of Polysorbate 80 solution in scintillation vials and these were then shaken in an incubator shaker at a constant temperature of 30ºC. The concentration of the leached DEHP was measured intermittently by HPLC (Waters 717 plus Autosampler), after every 18 hours over 72 hours. A calibration curve was created, and data was fitted to a linear regression.

Dimension Change Analysis:

            Films were cut into 5 mm x 1.5 cm strips and clamped. These were then loaded into a Thermo-Mechanical Analyzer (TI Q400) with a force of 0.05 N, ramp force of 0.015 N/min. to 0.15 N, and a preload force of 0.01 N.

Glass Transition Temperature:

            Films were cut into 5 mm x 1.5 cm strips and clamped. These were then loaded into a Thermo-Mechanical Analyzer (TI Q400) with a starting temperature of 0ºC, temperature change of 10ºC/min to 170ºC, and constant force of 0.05 N.

Extraction Resistance:

            The diblock plasticized films were analysed for extraction resistance in water by calculating mass change after immersing the films in distilled water for 24 hours.