###### Abstract  
Previous research extensively characterized PLA blends for various biomedical applications, especially in polymer-based biodegradable implant fixations, offering advantages over metallic counterparts. Nevertheless, achieving an optimal PLA mixture with both mechanical resistance and fast biodegradability remains a challenge. Currently, literature still lacks insights into the manufacturing parameter impact on sago starch/PLA in combination with PEG plasticizer. The objective of this study is to assess variations in injection molding temperatures and sago/PLA/PEG weight compositions to identify the optimal combination enhancing miniplate mechanical properties and biodegradation behavior. Mechanical tests reveal that incorporating PEG into pure PLA yields high mechanical performance, correlating linearly with increasing injection temperature. However, the interaction once the three materials are mixed decreases mechanical performance across tested temperatures. Higher biodegradation rates are observed with a larger weight composition of the hydrophilic behavior attributed to sago starch presence. The observed novelty in PLA mixed with 20% sago starch and 10% PEG at 170 \({}^{\circ}\)C indicates a better performance in elastic modulus and elongation at break also the degradation rate, emphasizing the role of injection temperature in molding miniplate implants. In conclusion, the interplay of injection molding parameters and material compositions is crucial for optimizing PLA-based miniplate implants, with potential contributions to tissue implants rather than bone implants due to their mechanical limitation. sago starch; degradable PLA; PEG plasticizer; degradable implant +
Footnote †: journal: Applied Sciences  
Article  
PLA-Sago Starch Implants: The Optimization of Injection Molding Parameter and Plasticizer Material Compositions  
[PERSON], [PERSON], Y.  
tensile strength and potential mismatches in degradability rates. Ideally, implants should degrade as fractures regain structural integrity during the recovery and growth process, acknowledging that bone remodeling can occur within three months to two years [8; 9]. Recent studies even suggest the remodeling starting as early as a month after a fracture, continuing beyond the typical two-month period [10]. In contrast, existing miniplate implants take approximately one to five years to degrade [5]. To address these challenges, new materials such as polylactic acid (PLA) have emerged, offering transient properties that commence with strength and support and gradually degrade over time, making space for newly grown bone to take over [11]. PLA stands out as the most commonly used biodegradable polymer in contemporary clinical applications [12]. Its versatility spans applications in drug delivery systems, tissue engineering and both temporary and permanent implantable devices, continually expanding into new fields [6]. This widespread use is attributed to PLA's favorable biocompatibility and the production of safe degradation devices, making it a prospective choice for temporary biomedical systems. PLA's primary monomeric building block exists in L-, D-, or both L/D-lactide forms, influencing the polymer's biodegradability and mechanical properties [13; 14; 15]. The primary mechanism of PLA degradation within the body is the hydrolysis of the ester-bond backbone, catalyzed by newly formed carboxylic groups at the end of cleaved PLA chains [16; 17]. However, PLA's inherent hydrophobic properties and resistance to hydrolysis result in a slow degradation rate of about two to five years in the crystalline phase hydrolysis [18]. Consequently, PLA may pose complications in tissues and prove unsuitable for use as medical appliances due to its extended degradation period, as observed in applications like surgical suture threads [5]. Blending PLA with natural-based composites or plasticizers stands out as an efficient method to address PLA's inherent disadvantages and broaden its applications [19; 20].