Polyester Resin based Corrosion Casting: Experimental mechanical characterization of rigid and flexible polymers for Anatomical purposes.
Authors: Rueda‐Esteban Roberto Javier , Lopez‐McCormick Juan Sebastian , Vargas Jose German , Bigio David , Briceño Juan Carlos 
Published: June 2021

Gross Anatomy learning requires Three Dimensional (3D) structural visualization in order to facilitate spatial relation and structural organization understanding. This educational process ‐ when related to the use of cadavers ‐ has been limited due to the difficulties in acquiring specimens and their reduced shelf life. Synthetic models offer a solution to said issues, in spite of not showing possible anatomical variations.

Multiple anatomical techniques have been developed to diminish preservation drawbacks. Among these, polymer corrosion casting (CC) permits the repletion of multiple ducts of an organ, later on, corroded by acid or alkali solutions. Polyester, Epoxy and Acrylic resins are the most widely used rigid polymers for CC due to their polymerized characteristics.

This technique has been widely used for education but the final polymeric matrix exhibit several disadvantages like use‐related deterioration due to fragility. However, the mechanical characteristics of the polymers have not been described when casted under an Anatomy Laboratory protocol and not using industrial processes.

Our aim was to determine the mechanical characteristics of a rigid polyester resin (RPR) as used for CC and to compare them when using a flexible polyester resin (FPR) as an additive or the FPR by itself. FPR was used to aggregate plastic properties to the RPR, in concentrations of 10% and 20% Weight/Weight (W/W).

Multiple standard tests were carried out to characterize the resins mechanically. Tensile and three‐point bending tests were performed with an Instron Machine 3367, and impact tests with a 43‐1TMI impact tester. Each test followed the ASTM standard methods D790, D689 and D256 respectively.

Mechanical properties such as modulus of elasticity (Young Modulus), maximum strength and ultimate strength were obtained from tension tests. Flexural modulus, maximum flexural strength, maximum deflection and maximum flexural strain were obtained by three‐point bending tests while impact energy was acquired from Impact tests.

Polymer behavior showed a remarkable correlation to FPR concentration when used as an additive for RPR, increasing significantly the plastic properties of the polymer. Under tension, the major Modulus of Elasticity (1,28 ± 0,40 GPa) was visible at low FPR ratios, in contrast with the FPR alone which presented an average of 16,98 ± 1,24 MPa. This tendency is supported by the elongation at rupture results which increased significantly from 3,20 ± 2,59% for 10% FPR/RPR to 107,19 ± 13,6% for FPR alone. On the other hand, three‐point bending exhibited a similar correlation reducing the flexural modulus by 1.87 times and the maximum flexural strength 2.04 times. Impact test allows to corroborate that FPR at 10% is more fragile than FPR alone with an Impact energy of 0,062 ± 0,006 and 1,32 ± 0,24 J/cm respectively.

In comparison, RPR alone results presented a Modulus of Elasticity of 1,11 ± 0,14 GPa, an elongation at rupture of 4,73 ± 1,43%, a flexural modulus of 2,35 ± 0,37 GPa, a maximum flexural strength of 74,15 ± 17,49 MPa and an impact energy of 0,055 ± 0,005 J/cm.

Our results not only demonstrate that using additives to aggregate plastic properties to a RPR increase its mechanical resistance to rupture but also provides important information about the mechanical properties of RPR and FPR at the time of selecting a polymeric polyester‐based formulation to preserve any specimen through CC.

This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.