# Heat-Resistant Behavior of PLA/PMMA Transparent Blends Induced by Nucleating Agents  
[PERSON]  
1 CCTEG Coal Mining Research Institute, Beijing 100020, China; [EMAIL_ADDRESS] (Y.F.); [EMAIL_ADDRESS] (Q.Y.) 12 State Key Laboratory of Coal Mining and Clean Utilization, Beijing 100013, China 23 School of Material Science and Engineering, Xihua University, Chengdu 610039, China; [EMAIL_ADDRESS] (Z.L.); [EMAIL_ADDRESS] (Z.Z.) 24 Correspondence: [EMAIL_ADDRESS] (Tel./Fax: +86-010-62019922 4 These authors contributed equally to this work. 2525156738 24 April 202516  
and heat resistance. However, this specialized nucleating agent exhibited unsatisfactory crystallization solidification during actual processing and a limited ability to improve mechanical properties. Furthermore, due to the uncontrollable crystal size, the refractive index differences between the crystalline and amorphous regions resulted in unstable mechanical properties, severely affecting the PLA transparency [6].  
PLA can be combined with polymethyl methacrylate (PMMA) [7] and polycarbonate (PC) to improve its mechanical properties without reducing its transparency [8]. The PLA/PMMA blend system demonstrates significant potential in advanced packaging applications, particularly in sustainable food packaging and high-temperature resistant containers. Since its refractive index is close to that of PLA (1.49-1.50), PMMA is a preferred resin for simultaneously improving heat resistance and transparency, exhibiting a high glass transition temperature (T\({}_{\mathrm{g}}\)), and excellent compatibility, transparency, and durability [9; 10]. [PERSON] et al. [11] used a semi-industrial twin-screw extruder and injection molding as preparation methods, resulting in semi-transparent PLA/PMMA blends. [PERSON] et al. [12] prepared transparent PLA/PMMA blends via melt blending. The results revealed partially crystallized PLA, while the presence of spherulites increased the overall heat resistance of the material. Although PMMA addition restricted the size of the PLA spherulites and improved the blend transparency, it reduced the nucleation and spherulite growth rates [12; 13].  
Although several studies have examined PLA/PMMA blends and the addition of nucleating agents to control PLA crystallization kinetics [14; 15], minimal research is available regarding nucleating agent addition to PLA/PMMA blend systems. Therefore, this study investigates the relationship between nucleating agents and the crystalline structure and properties of the blend system. Furthermore, according to the International Organization for Standardization (ISO), when the relative biodegradation rate of a completely degradable plastic exceeds 90%, it is considered fully degraded by microorganisms [16]. PLA belongs to the category of fully biodegradable materials, while PMMA is non-biodegradable. Considering the requirements for biodegradability while improving the heat resistance of PLA, the PMMA content added in this study is 10%. This material system successfully addresses the conflicting demands of thermal resistance, optical clarity, and biodegradability in modern packaging through PMMA-induced spherulite size reduction and hydrogen-bonding nucleating agents.