Page 23 - eBook_Proceedings of the International Conference on Digital Manufacturing V1

Degradation Analysis of 3D Printed PLA in Simulated Body

using standard buffer solutions (pH 4.00, 7.00 and 10.00) to
ensure measurement accuracy.

At each time point, the entire container—including both the
PLA sample and the corresponding volume of SBF—was used as
a single-use unit.

The pH was measured directly in the container without
transferring the solution to another vessel. After the pH
measurement and subsequent sample collection for mass loss
analysis, both the sample and the SBF were discarded. This single-
use approach eliminated the risk of cross-contamination between
time points and ensured consistent experimental conditions.

In addition to recording the pH values, the percentage change
in pH (ΔpH%) relative to the initial SBF pH (pH0 = 7.40) was
calculated using Equation (2):

− (2)
∆ %= × 100

where pHt represents the pH at each degradation time point. This
calculation helps quantify the relative acidification of the SBF
solution caused by PLA hydrolysis. All measurements were
conducted in triplicate to ensure data reliability and
reproducibility.

RESULTS AND DISCUSSION

Weight Loss Analysis

The weight loss behaviour of the 3D-printed PLA samples was
assessed over a 28-day degradation period in SBF. As shown in
Figure 1, all three geometries (Cube, Dogbone and Bar) exhibited
a progressive increase in weight loss percentage over time,
indicating gradual hydrolytic degradation of the PLA material
(Tsuji, 2022).

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