# Effect of LNR-g-MMA on the Mechanical Properties and Lifetime Estimation of PLA/PP Blends
## 1 Introduction  
In recent years, plastic waste has been increasing. The majority of plastic waste is generated from the petroleum industry, which cannot be replaced and degraded naturally. The disposal methods of these plastics are land-filled or incinerated, and some of them can be renewable [1; 2; 3]. They are one of the causes of severe environmental pollution. Therefore, this research was focused on the use of biodegradable polymers. Polylactide (PLA), a biodegradable polyester obtained by the synthesis of lactic acid produced via the fermentation of carbohydrate crops, has a good tensile strength and stiffness compared to general commercial polymers. Therefore, PLA is widely used as a packaging material, such as high\(-\)value films, coated paper packaging, and food and beverage containers [4; 5]. However, the use of PLA has several limitations: they are brittle, possess a low impact resistance, and are costly [4; 6]. Hence, improving the properties or limitations of general polymers can be undertaken through many methods, such as plasticization, chemical modification, and blending with other polymers, which is the most popular method. The blending of PLA with other tough polymers and thermoplastic elastomeric polymers, such as linear low density polyethylene (LLDPE) [6], poly(propylene carbonate) (PPC) [7], epoxidized natural rubber (ENR) [8], poly(bulylene succinate\(-\)butylene terephthalate)(PBST) [9], polyhydroxybutyrate (PHB) [10], or polypropylene (PP) [2; 3; 11; 12; 13; 14; 15], is regarded as a useful and economical way to overcome these limitations. The advantages of polymer blends result in new materials with a wide range of properties at a lower cost and higher efficiency compared to other methods. PP has outstanding mechanical properties, such as toughness, non\(-\)brittleness, and impact resistance, it is non-toxic and is cheap [16; 17]. Thus, the PP/PLA blend is quite interesting and can create materials with an improved moisture resistance, mechanical properties, impact resistance, and flexural modulus. However, the polymer blend of PLA/PP is immiscible due to PLA and PP being polar and non\(-\)polar substances, respectively [18]. This results in poorer mechanical properties. The compatibility of PLA/PP depends on interfacial tension and adhesion between the two phases. A compatibilizer can be added to improve the compatibility of immiscible blends [2; 3; 11; 12; 14; 18]. Numerous published research studies [3; 12; 14; 18] have been reported on PLA/PP blends using polypropylene\(-\)g\(-\)maleic anhydride (PP\(-\)g\(-\)MAH) as a compatibilizer to enhance the miscibility and decrease the interfacial tension between PLA and PP. [PERSON] et al. [3] prepared a blend of PLA and PP at various ratios (PLA:PP = 90:10, 80:20, 70:30, and 50:50) using reactive compatibilizers PP\(-\)g\(-\)MAH and glycidyl methacrylate (GMA) to induce miscibility. They found that adding PP\(-\)g\(-\)MAH, a compatibilizer, decreased the dispersed phase's domain size and increased the mechanical characteristics of PLA/PP/PP\(-\)g\(-\)MAH. [PERSON]\(-\)[PERSON] et al. [12] reported polymer blends with PLA/PP ratios of 80:20 and 20:80, and 1, 3, and 5 wt% PP\(-\)g\(-\)MAH. Thermal, mechanical, and morphological analyses were performed on dry blend injection\(-\)molded samples. The thermal investigation showed that PP\(-\)g\(-\)MAH did not affect the polymer components' crystalline melting temperature, but it improved impact strength. [PERSON] et al. [18] studied the effects of compatibilizers and hydrolysis on the tensile and impact strength, interfacial tension, and morphology of PP/PLA (80:20) blends with PP\(-\)g\(-\)MAH and styrene\(-\)ethylene\(-\)butylene\(-\)styrene\(-\)g\(-\)maleic anhydride (SEBS\(-\)g\(-\)MAH) as compatibilizers. They found that SEBS\(-\)g\(-\)MAH did not affect the compatibility of PP/PLA (80:20) blends. The impact strength of PP/PLA (80:20) blends increased with SEBS\(-\)g\(-\)MAH, suggesting that PP\(-\)g\(-\)MAH may operate as an impact modifier. [PERSON] et al.