A Comparative Study on the Mechanical, Thermal and Morphological Characterization of Poly(lactic acid)/Epoxidized Palm Oil Blend

In this work, poly(lactic acid) (PLA) a fully biodegradable thermoplastic polymer matrix was melt blended with three different epoxidized palm oil (EPO). The aim of this research was to enhance the flexibility, mechanical and thermal properties of PLA. The blends were prepared at various EPO contents of 1, 2, 3, 4 and 5 wt% and characterized. The SEM analysis evidenced successful modification on the neat PLA brittle morphology. Tensile tests indicate that the addition of 1 wt% EPO is sufficient to improve the strength and flexibility compared to neat PLA. Additionally, the flexural and impact properties were also enhanced. Further, DSC analysis showed that the addition of EPO results in a decrease in Tg, which implies an increase in the PLA chain mobility. In the presence of 1 wt% EPO, TGA results revealed significant increase in the thermal stability by 27%. Among the three EPOs used, EPO(3) showed the best mechanical and thermal properties compared to the other EPO’s, with an optimum loading of 1 wt%. Conclusively, EPO showed a promising outcome to overcome the brittleness and improve the overall properties of neat PLA, thus can be considered as a potential plasticizer

Mechanical, Thermal and Morphological Properties of Poly(lactic acid)/Epoxidized Palm Olein Blend

Poly(lactic acid) (PLA) is known to be a useful material in substituting the conventional petroleum-based polymer used in packaging, due to its biodegradability and high mechanical strength. Despite the excellent properties of PLA, low flexibility has limited the application of this material. Thus, epoxidized palm olein (EPO) was incorporated into PLA at different loadings (1, 2, 3, 4 and 5 wt%) through the melt blending technique and the product was characterized. The addition of EPO resulted in a decrease in glass transition temperature and an increase of elongation-at-break, which indicates an increase in the PLA chain mobility. PLA/EPO blends also exhibited higher thermal stability than neat PLA. Further, the PLA/1 wt% EPO blend showed enhancement in the tensile, flexural and impact properties. This is due to improved interaction in the blend producing good compatible morphologies, which can be revealed by Scanning Electron Microscopy (SEM) analysis. Therefore, PLA can be efficiently plasticized by EPO and the feasibility of its use as flexible film for food packaging should be considered

Graphene nanoplatelets as novel reinforcement filler in poly(lactic acid)/epoxidized palm oil green nanocomposites: Mechanical properties

Abstract: Graphene nanoplatelet (xGnP) was investigated as a novel reinforcement filler in mechanical properties for poly(lactic acid) (PLA)/epoxidized palm oil (EPO) blend. PLA/EPO/xGnP green nanocomposites were successfully prepared by melt blending method. PLA/EPO reinforced with xGnP resulted in an increase of up to 26.5 % and 60.6 % in the tensile strength and elongation at break of the nanocomposites respectively, compared to PLA/EPO blend. XRD pattern showed the presence of peak around 26.5 ° in PLA/EPO nanocomposites which corresponds to characteristic peak of graphene nanoplatelets. However, incorporation of xGnP has no effect on the flexural strength and modulus. Impact strength of PLA/5 wt % EPO improved by 73.6 % with the presence of 0.5 wt % xGnP loading. Mechanical properties of PLA were greatly improved by the addition of a small amount of graphene nanoplatelets (<1 wt%)

A systematic review of self-regulated learning in flipped classrooms: key findings, measurement methods, and potential directions

Online instruction through a flipped classroom approach has continued to gain popularity in recent years. Engaging learners’ attention in achieving learning outcomes while embracing the flexibility of online learning via flipped classrooms remains an essential topic among educators, educational institutions, and society. Studies have found that students equipped with self-regulated learning strategies thrive in such learning environments. The present study describes and analyses the state of research in self-regulated learning strategies and their association with the flipped classroom based on the review of articles published in Q1 and Q2 journals from 2016 to the middle of 2021. The instructions in PRISMA guided the development of systematic review protocols. Thirty-two scientific texts from four search databases, Science Direct, Scopus, ERIC, and ProQuest, were reviewed. The key findings present the effects of self-regulation on academic and non-academic outcomes and the factors that influenced the outcomes. The findings also revealed six preferred methods to measure self-regulated learning in a flipped classroom, specifically through self-report questionnaires, as the most preferred approach, followed by learning analytics, interviews, think-aloud protocols, reflective documents, and observation. Furthermore, the potential future areas of study are detailed as prospect references. In conclusion, it is highly recommended for educators and future studies to integrate the essential characteristics of flipped learning as pointed out by the four pillars (F-L-I-P): flexible environment, learning culture, intentional content, and professional educator. Ultimately, this justifies the successful integration of the flipped classroom into learning and facilitates the development of self-regulated learning strategies