# Effect of LNR-g-MMA on the Mechanical Properties and Lifetime Estimation of PLA/PP Blends
## 4 Conclusions  
This study aimed to investigate the effect of LNR\(-\)g\(-\)MMA content on the morphology, mechanical properties, water absorption, thermal degradation, and a lifetime of blends based on PLA and PP. PLA polymer, PP polymer, and PLA/PP (70:30 wt%) blend, with  
Figure 10: Thermal lifetime estimation for PLA, PP, and PLA/PP (70:30 wt%) without and with compatibilizer as obtained for different operating temperatures (T\({}_{\rm{T}}\)) at 20 \({}^{\circ}\)C/min and w = 0.05.  
Figure 9: Dependence of the activation energy of PLA, PP, and PLA/PP (70:30 wt%) blends without and with a compatibilizer as a function of the degrees of conversion obtained from the KAS method applied to thermal decomposition.  
LNR\(-\)g\(-\)MMA as compatibilizers with a content of 0.0, 2.5, 5.0, and 10.0 phr, respectively, were prepared by internal mixing and compression molding. SEM revealed that the PLA/PP blend underwent phase separation, resulting in the dispersion of PP in the form of small balls distributed evenly in the PLA matrix. When the presence of LNR\(-\)g\(-\)MMA increased, the PP droplet sizes reduced considerably, with an almost homogenized and refined blend morphology. LNR\(-\)g\(-\)MMA was added as a compatibilizer to improve the compatibility between PLA and PP. The neat PLA and PP has a tensile strength of 55.31 and 31.61 MPa and an elongation at break of 3.85 and 19.60%, respectively. However, an increasing trend of tensile strength and elongation at break of the polymer blends was observed, slightly increasing from 25.78 to 29.35 MPa and from 3.59 to 5.56%, respectively, with an increase in the LNR\(-\)g\(-\)MMA content from 0.0 to 10.0 phr, respectively. PLA displayed an impact strength of 2.75 kJ/m\({}^{2}\), indicating a brittle polymer. In the PLA/PP (70:30 wt%) system, an increasing trend was observed for the impact strength of the polymer blends, which slightly increased from 3.09 to 3.57 kJ/m\({}^{2}\) as the LNR\(-\)g\(-\)MMA content increased from 0.0 to 10.0 phr. Overall, the results showed that the values of tensile strength, elongation at break, and impact strength of the polymer blends increased, whereas water absorption values decreased with an increase in LNR\(-\)g\(-\)MMA content. Thermal degradation kinetics was studied over a temperature range of 50-800 \({}^{\circ}\)C, at multiple heating rates of 10, 20, 30, and 40 \({}^{\circ}\)C/min. When PLA was blended with PP at 70:30 wt%, the blend was more stable or resistant to temperature than PLA. However, the addition of LNR\(-\)g\(-\)MMA as a compatibilizer decreased the blend's thermal stability by increasing interfacial adhesion and interaction between the polymer phases. The above results suggested that adding PP to the PLA matrix increased the activation energy. Comparatively, adding a compatibilizer enhanced the compatibility of two polymers and decreased activation energy, thus decreasing the blends' thermal stability. Due to the lifetime calculated from the E\({}_{\text{a}}\) values of the polymers, PP was more durable than PLA and the PLA/PP (70:30 wt%) blend. The PLA/PP (70:30 wt%) blend without LNR\(-\)g\(-\)MMA had a longer lifetime than those with LNR\(-\)g\(-\)MMA. A material's thermal stability can influence the processing and applications of polymeric materials, thus necessitating knowledge of their thermal lifetime under a particular end-point criterion and operating temperature.  
Writing--original draft preparation, K.W.; writing--review and editing, W.P. and W.A. All authors have read and agreed to the published version of the manuscript.  
This research was funded by the Thailand Research Fund (TRF) under the Royal Golden Jubilee Ph.D. Program, grant number PHD/0209/2558.  
Not applicable.  
All the data is included in the article.  
The authors gratefully acknowledge the financial support of the Thailand Research Fund (TRF) and Silpakorn University through the Royal Golden Jubilee Ph.D. Program grant #PHD/0209/2558.  
The authors declare no conflict of interest.