Nowadays, extensive environmental problems due to the use of synthetic polymers have provoked efforts for their replacement with biopolymers as the most important research priorities. Polylactic acid (PLA) is one of the well-known biodegradable biopolymers. In this work, for the first time, PLA was modified with hydrophilic triazine-based dendrimers to obtain PLA with improved hydrophilic properties. In this regard, at first, dl-lactic acid (DLLA) was polymerized through the melt polycondensation to obtain poly-dl-lactic acid (PDLLA). The effects of reaction time and catalyst types on the molecular weight of the PDLLA were investigated. Also, the thermal behavior of PDLLAs with different molecular weights was evaluated using differential scanning calorimetry (DSC) technique. The obtained results from the DSC analysis showed that the PDLLA with higher molecular weight has a higher glass transition temperature (T_g) and melting point (T_m). In the following, various generations (G) of the triazine-based dendrimers were synthesized. To increase the hydrophilicity of the prepared PDLLA, chemical modification of PDLLA with the different generations of triazine-based dendrimer (G₁, G_1.5 and G₂) was performed. Due to the modification of PDLLA with dendrimers, the number of functional groups and hydrophilicity of PDLLA increased. Based on the obtained results, it is expected that the prepared systems could be a good and promising candidate for the production of biocompatible plastics with more hydrolytic degradation ability.

中文翻译：

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星形聚乳酸基三嗪树枝状大分子：催化剂类型和时间因素对聚乳酸分子量的影响

如今，由于使用合成聚合物而引起的广泛的环境问题促使人们努力将其替换为生物聚合物，将其作为最重要的研究重点。聚乳酸（PLA）是众所周知的可生物降解的生物聚合物之一。在这项工作中，首次用亲水性三嗪基树枝状聚合物对PLA进行了改性，从而获得了具有改善的亲水性的PLA。在这方面，首先，通过熔融缩聚使dl-乳酸（DLLA）聚合以获得聚dl。-乳酸（PDLLA）。研究了反应时间和催化剂类型对PDLLA分子量的影响。此外，使用差示扫描量热法（DSC）技术评估了具有不同分子量的PDLLA的热行为。从DSC分析获得的结果表明，具有较高分子量的PDLLA具有较高的玻璃化转变温度（T _g）和熔点（T _m）。在下文中，合成了三代的基于三嗪的树枝状大分子。为了增加制备的PDLLA的亲水性，请使用不同代的三嗪基树枝状大分子（G ₁，G _1.5和G ₂）。由于用树枝状聚合物修饰了PDLLA，所以PDLLA的官能团数和亲水性增加了。基于获得的结果，预期制备的系统将是生产具有更高水解降解能力的生物相容性塑料的良好且有前途的候选者。