###### Abstract
Studies [21; 22; 23; 24] have successfully demonstrated the positive impact of starch incorporation into PLA composites, enhancing both mechanical and biocompatibility performances for medical applications. However, the utilization of sago starch as a natural-based polymer in PLA implants presents a promising yet limited understanding [25; 26; 27]. Recognized for its ability to improve biodegradability, non-toxicity and its consideration as a renewable resource, sago starch encounters challenges in achieving homogeneity, often leading to agglomeration and poor bonding with other materials due to its hydrophilic characteristics [28; 29]. To address these challenges, additional polymers such as polyethylene glycol (PEG) are introduced to enhance cohesion among the phase materials. In PLA-based implants, PEG enhances hydrophilicity, surface wettability, elongation percentage and impact strength through copolymerization with PLA [30; 31]. However, literature on PLA-based performance in combination with both sago starch and PEG as the plasticizer material remains limited [27]. The addition of starch and PEG can decrease mechanical strength, necessitating careful observation and formulation of the mixing proportions to ensure sufficient strength in PLA products. Adding PEG to the PLA/starch mixture at an 80:20 ratio, based on previous research [32], aims to achieve a balance of strength and stiffness. Exceeding 20% starch addition significantly reduces tensile strength and elongation at the break of PLA. The study explores two variations of PEG addition: 10% and 20% by weight of the PLA/starch mixture, revealing that 10% PEG is more effective in increasing break elongation compared to 20% PEG. Previous findings indicated that adding sago starch up to 20% \(w/w\) maintained tensile strength at over 60% of pure PLA, while concentrations beyond that significantly reduced strength to below 36% of pure PLA [27]. PEG increased tensile and bending elongations at break and flexural strength compared to sago starch/PLA blends but reduced tensile strength and elastic modulus, obtained after injection molding at 180 \({}^{\circ}\)C. Thermochemical manipulation during the injection molding process, particularly with orientation control systems (SCORIM), can enhance PLA's mechanical properties. SCORIM has been successfully applied to starch-PLA mixture materials for medical applications, as reported in previous study [27]. However, the optimal temperature and polymeric mate rial compositions for achieving the desired properties in PLA-based miniplates implants remain unclear. In short, previous studies have extensively characterized PLA blends for diverse biomedical applications [21; 22]. Additionally, a comprehensive examination of a sago starch/PLA/PEG compound, fabricated into miniplate samples with a focus on physico-chemical and mechanical properties, has been reported in the previous paper [27]. However, there is a notable gap in the literature concerning the impact of the manufacturing process when producing PLA in combination with the starch and the plasticizer. Therefore, it is hypothesized that by understanding the balance of injection molding parameter and the mixture composition, the functionality of the PLA-based miniplate implant could be improved. This research aims to assess the effects of variations in injection molding temperatures and sago/PLA/PEG weight compositions to identify the optimal combination for enhancing the mechanical properties and biodegradation behavior of the miniplates. The reported mechanical properties involve the results of tensile and bending tests, revealing information about the strength, elastic modulus and elongation at break of the miniplates. The study also observes the biodegradation performance, aiming to determine if the miniplates exhibit faster degradation compared to the existing result within the observed time period.