The 3d Printability and Mechanical Properties of Polyhydroxybutyrate (PHB) as Additives in Blends Polymer for 3d Printed Arm Cast

Additive manufacturing, widely known as three-dimensional (3D) printing is a
substantial part of in Forth Industrial Revolution (IR 4.0) for the manufacturing
ecosystem across a plethora of industrial sectors including electronics, automotive and
medical. Within the medical industry, stereolithography (SLA) technique emerges as
one of the predominant techniques due to the high-resolution capabilities which is better
compared to other additive manufacturing technique. This research aims to utilize
blended materials technique in the SLA process with using
polyhydroxybutyrate/urethane dimethacrylate (PHB/UDMA) combination to fabricate
a new 3D printed materials for medical application in particular arm cast. Viscosity
plays a crucial role in the printability of the 3D printed resins. For this research, the
maximum viscosity was achieved at approximately 2188 centipoise (cP) with the
concentration of PHB at 11% weight ratio. Based on this composition, the tensile and
impact strength were able to maintain with a minimal degradation of only 3% relative
to the pure UDMA resin which is at 16% in a one month period. The inclusion of PHB
is attributed to the structural integrity and stability of the 3D printed materials. Based
on the clinical application standards, only 3% by weight composition of PHB failed to
meet the requirements for the degree of double bond conversion (DC). These are good
indications as most of the composition shows a more complete polymerization process
which leads to better performance. For the crystallinity index, the inclusion of PHB
contributed towards crystalline structures within UDMA based resin and make the 3D
printed PHB/UDMA more prone to fracture, thus in line with the reduction of
mechanical performance. Meanwhile, FESEM pictures portrayed two distinct phases
region between PHB and UDMA proved the poor interfacial adhesion between the
polymer blend. Based on the overall results, 7 wt. % of PHB content was selected as an
optimal blending mixture composition for 3D printed arm cast due to better mechanical
performance and passed the minimum standard level of DC. This research shows
significant contributions in understanding the relationship between printability and
mechanical properties of PHB/UDMA resins in particular for 3D printed arm cast using
SLA technique.