聚乳酸的合成方法

聚乳酸是一类具有优良生物相容性和可生物降解的高分子材料，被广泛应用于医用领域，受到越来越多的关注。聚乳酸的合成主要有两种方法：丙交酯的开环聚合和乳酸直接缩聚。综述近年来聚乳酸合成研究的最新进展，介绍了聚乳酸聚合的两种高效方法-反应挤出法和直接-固相聚合法．并展望了聚乳酸合成研究的前景。     

溶液直接缩聚法合成聚乳酸的特点

聚乳酸具有良好的生物相容性、生物降解性和牛物可吸收性,它被广泛用作药物缓释、手术缝合线及骨折内固定等生物医用高分子材料.文章探讨了近年来国内外研究溶液直接缩聚法合成聚乳酸的进展情况,概述了乳酸溶液直接缩聚的原理,研究了溶液聚合中影响聚乳酸相对分子质量的因素.开展聚乳酸直接合成方法的研究,具有非常重要的意义,期望能通过对溶液聚合中影响聚乳酸相对分子质量的因素进行研究,改进聚乳酸的直接合成工艺,通过直接合成法得到较高相对分子质量的聚乳酸.     

表面改性聚合物左旋聚乳酸-多聚赖氨酸可促进骨髓基质细胞的初始黏附

背景：通过增加表面活性基团对生物支架材料进行表面改性,可提高材料对细胞的亲和力,有效提高材料的细胞相容性。目的：合成表面改性聚合膜左旋聚乳酸-多聚赖氨酸（PLLA-PLL）,并观察其对骨髓基质细胞黏附、增殖的影响。方法：通过开环聚合反应合成不同组分高分子聚合膜PLLA139-PLL131,PLLA77-PLL72,PLLA45-PLL246,将人骨髓基质细胞接种至不同组分聚合膜PLLA-PLL表面、左旋聚乳酸及商品化的细胞培养板,寻找最佳PLLA-PLL组分。结果与结论：与左旋聚乳酸比较,不同组分PLLA-PLL聚合膜细胞黏附量均升高,以PLLA77-PLL72聚合膜组增高显著（P〈0.05）,所以最佳组分为PLLA77-PLL72,连续培养结果显示PLLA77-PLL72聚合膜表面骨髓基质细胞骨架蛋白表达丰富,清晰有序,增殖实验也证实了PLLA77-PLL72聚合膜可促进骨髓基质细胞增殖。     

表面改性聚合物左旋聚乳酸-多聚赖氨酸可促进骨髓基质细胞的初始黏附

背景:通过增加表面活性基团对生物支架材料进行表面改性,可提高材料对细胞的亲和力,有效提高材料的细胞相容性。目的:合成表面改性聚合膜左旋聚乳酸-多聚赖氨酸(PLLA-PLL),并观察其对骨髓基质细胞黏附、增殖的影响。方法:通过开环聚合反应合成不同组分高分子聚合膜PLLA139-PLL131,PLLA77-PLL72,PLLA45-PLL246,将人骨髓基质细胞接种至不同组分聚合膜PLLA-PLL表面、左旋聚乳酸及商品化的细胞培养板,寻找最佳PLLA-PLL组分。结果与结论:与左旋聚乳酸比较,不同组分PLLA-PLL聚合膜细胞黏附量均升高,以PLLA77-PLL72聚合膜组增高显著(P<0.05),所以最佳组分为PLLA77-PLL72,连续培养结果显示PLLA77-PLL72聚合膜表面骨髓基质细胞骨架蛋白表达丰富,清晰有序,增殖实验也证实了PLLA77-PLL72聚合膜可促进骨髓基质细胞增殖。     

可注射生物降解聚合物聚乳酸羟基乙酸-聚乙二醇-聚乳酸羟基乙酸温敏凝胶的体外释药行为

背景：蓖麻毒素具有强烈的细胞毒活性,但缺乏特异性,全身用药可导致严重毒副作用,采用缓释载体包载进行间质化疗可达到提高肿瘤局部治疗效应,并且避免全身毒性的效果。目的：制备可注射可生物降解的聚乳酸羟基乙酸-聚乙二醇-聚乳酸羟基乙酸温敏型凝胶,观察其作为蓖麻毒素缓释载体的体外药物释放行为。设计、时间及地点：对比观察实验,于2007/08-12在福建医科大学医药生物工程中心完成。材料：蓖麻毒素由福建省超声医学研究所纯化,纯度达95%。DL-丙交酯、L-乙交酯由北京元生融科技有限公司提供。方法：采用开环聚合法合成聚乳酸羟基乙酸-聚乙二醇-聚乳酸羟基乙酸聚合物。主要观察指标：试管翻转法测定相转变温度,高效凝胶渗透色谱法测定相对分子质量,核磁共振推测聚合物嵌段比例,酶联免疫吸附法测定凝胶包载蓖麻毒素的体外释放行为,高效液相色谱法检测释放蓖麻毒素结构完整性,MTT法测定体外释放蓖麻毒素的细胞毒活性。结果：合成的聚合物具有反向热敏性,质量浓度为230g/L时的相转变温度为26℃。聚合物质均分子质量为8027,数均分子质量为6643,多元分散系数为1.17,聚乙二醇与聚乳酸嵌段比例约为3∶2。载药凝胶在体外持续释放蓖麻毒素达18d,并且较好地保持了蓖麻毒素结构稳定性和细胞毒活性。结论：合成的聚乳酸羟基乙酸-聚乙二醇-聚乳酸羟基乙酸聚合物是蓖麻毒素较理想的药物缓释载体。     

医用聚乳酸类高分子材料的应用

目的:阐述医用聚乳酸类高分子材料的需求,综述聚乳酸类高分子材料在生物医学领域的应用,并对其在医学领域的应用前景进行展望。资料来源:应用计算机检索ACS美国化学学会数据库2000-01/2006-12关于医用聚乳酸类高分子材料的文章,检索词“polylactide”;利用Elsevier Science全文电子期刊数据库2000-01/2006-12进行检索,检索词“polylactide”和全文检索“Medical polymeric material”。同时利用计算机检索中国期刊全文数据库1994-01/2005-12的相关文章,限定文章语言种类为中文,检索词“聚乳酸类医用高分子材料”。资料选择:对资料进行初审,纳入标准:①关于聚乳酸类医用高分子材料的需求。②医用聚乳酸类高分子材料的合成及应用。排除标准:重复性研究。资料提炼:共收集到符合上述要求的文献100篇,排除70篇重复性研究。30篇符合纳入标准:其中6篇关于聚乳酸类医用高分子材料的需求,24篇关于医用聚乳酸类高分子材料的合成及应用。资料综合:聚乳酸是一种具有良好的生物相容性和可生物降解的聚合物,最终的降解产物是二氧化碳和水,对人体无毒、无刺激。目前,聚乳酸类材料产品在医学领域广泛用于药物控制释放载体、组织工程、骨内固定、修复、手术缝合线、人造皮肤以及三维多孔支架等。结论:医用聚乳酸类高分子材料有非常广阔的应用前景,今后研究的重点是研发高效低成本的聚乳酸制备方法,合成适应于不同医疗或其他用途的、具有优良生物相容性的聚乳酸共聚物高分子材料。     

“刚／柔”可控的新型聚氨酯材料的制备与表征

背景：生物可降解聚氨酯是生物医用材料领域研究的-个热点。基于聚乳酸的智能型聚聚氨在生物医学领域具有广阔的应用前景。目的：以D，L-丙交酯、1，6-六亚甲基二异氰酸酯、1，4-丁二醇和1，4-丁二胺作为原料，从分子设计角度出发，制备-种基于聚乳酸的“刚，柔”可控多嵌段聚氨酯材料。方法：采用熔融聚合法首先合成羟基封端聚（D，L-乳酸），加入六亚甲基二异氰酸酯作为交联剂，再聚合得到基于聚（D，L-乳酸）的聚氨酯。通过红外光谱仪、核磁共振波谱仪、热重，差热综合热分析仪、万能材料试验机等仪器对羟基封端聚（D，L-乳酸）及基于聚（D，L-乳酸）的聚氨酯进行结构表征和性能测试。结果与结论：实验发现，经熔融聚合后的产物与预期分子结构设计相符，通过调节材料中反应物的比例调节硬段和软段的比例，从而实现调控该材料“刚，柔”转变程度（断裂伸长率从472％-112％）和“刚，柔”转变温度（玻璃化转变温度从36．33-44．04℃）。结果表明由可降解生物材料制备的基于聚（D，L-乳酸）的聚氨酯材料具备热敏效应，且其断裂伸长率和玻璃化转变温度可控，具备应用于生物医学工程领域的基础。     

混杂结构聚乳酸／钙磷盐／胶原骨支架的表面处理研究

目的：将聚乳酸／钙磷盐／胶原复合材料作为制造骨组织工程支架的材料。方法：采用碱式反应法和共混法获得两种胶原／钙磷盐复合材料，然后通过真空吸附法在聚乳酸／磷酸三钙的支架表面沉积胶原，又通过碱式反应法沉积钙磷盐。结果：观测碱式反应法合成胶原-钙磷盐复合材料：胶原交联纤维束间形成薄膜状粘连。共混法获得胶原-钙磷盐复合材料显示：钙磷盐和胶原海绵紧密结合。快速成形工艺获得混杂结构支架可见：最后用碱式反应法合成的片状钙磷盐颗粒沉积在胶原海绵的表面。结论：此法获得了具有混杂结构的支架，可以应用于骨的修复。     

生物降解材料聚L-乳酸的熔融缩聚合成

背景：通过对合成工艺和催化剂的优化和选择，合成较高相对分子质量的聚乳酸生物降解材料。方法：实验于2003-02/2004-10在哈尔滨工业大学市政环境工程学院绿色化学与技术研究中心完成。以L-乳酸为原料，通过熔融缩聚的一步法合成可生物降解的聚L-乳酸。乳酸首先在无催化剂存在条件下发生自催化缩聚反应，生成较低相对分子质量的预聚物OLLA;然后将催化剂加入到OLLA中继续反应，最后得到较高相对分子质量的聚乳酸。实验考察了预聚条件、催化剂种类和用量、催化剂溶解程度、聚合温度及反应时间对聚乳酸分子量的影响。采用傅立叶变换红外光谱仪和核磁共振氢谱对聚合物结构进行了分析确认，通过凝胶气相色谱测定了聚合物的相对分子质量分布。结果：L-乳酸在140℃下，先在30kPa下脱水反应2h；然后减压至5kPa继续反应4h，可得到黏均相对分子质量（Mη）为6500左右的OLLA。以SnCl2-TSA复合体系为催化剂，按SnCl2与OLLA质量比=0．4％，TSA：SnCl2=1．0（mol／mol）的用量和配比，将催化剂加入OLLA中并充分溶解后，在165℃左右，5kPa下搅拌反应8h左右，至反应物出现爬杆现象时终止反应，可得到Mη约为65000的聚L-乳酸。结论：在优化的工艺条件和催化剂下，能够在较短时间（8h）内获得较高相对分子质量的聚L-乳酸，使该生物降解材料具备了一定的实用价值。     

混杂结构聚乳酸/钙磷盐/胶原骨支架的表面处理研究

目的将聚乳酸/钙磷盐/胶原复合材料作为制造骨组织工程支架的材料.方法采用碱式反应法和共混法获得两种胶原/钙磷盐复合材料,然后通过真空吸附法在聚乳酸/磷酸三钙的支架表面沉积胶原,又通过碱式反应法沉积钙磷盐.结果观测碱式反应法合成胶原-钙磷盐复合材料胶原交联纤维束间形成薄膜状粘连.共混法获得胶原-钙磷盐复合材料显示钙磷盐和胶原海绵紧密结合.快速成形工艺获得混杂结构支架可见最后用碱式反应法合成的片状钙磷盐颗粒沉积在胶原海绵的表面.结论此法获得了具有混杂结构的支架,可以应用于骨的修复.     

聚乳酸膜等离子接枝聚合聚乙烯基吡咯烷酮及表面性能研究

背景:由于聚乳酸表面亲水性差、缺乏天然分子识别位点等缺点而限制了其应用.通过复合、化学接枝等方法试图引进亲水性基团,但过程比较复杂,并应用大量有机试剂,影响材料的生物相容性.目的:利用低温等离子技术对聚乳酸进行表面改性,改善其亲水性.设计:对比观察.单位:暨南大学科学与工程系.材料:实验于2004-10/2005-10在广州人工器官和材料工程研究中心实验室完成.实验用主要材料:聚乳酸(Mr 29 000,山东医疗器械研究所),乙烯基吡咯烷酮(美国Acros公司,使用前经重蒸纯化).方法:通过改变不同的工作条件(功率=150 W,时间=3,2,1 min;功率=30 W,t=10,8,5,3,1 min)选择优化条件,然后通过气相法和常压液相法进行PLA-乙烯基吡咯烷酮接枝反应.主要观察指标:通过扫描电镜和原子力显微镜观察材料的表面形态;水接触角测量仪测定材料等离子处理和等离子接枝前后亲水性的变化;傅里叶变换红外光谱仪测定材料的结构变化;通过材料改性前后质量变化分析材料的接枝情况.结果:①扫描电镜显示等离子处理和接技后的材料表面呈现大小不一的气孔和沟痕.②接枝后的水接触角由原来的78°下降到50°.③傅里叶变换红外光谱图表征1750cm-1吸收峰的低波数侧1 637.19 cm-1出现新的吸收峰,该峰对应于聚乙烯基吡咯烷酮链段上酰胺基团中的羰基伸缩振动吸收.④聚乳酸膜材料经低温等离子处理后,材料的质量变化百分数为-0.6.结论:等离子处理和接枝后材料的亲水性有明显变化,材料表面呈现大小不一的气孔和沟痕.此表面有利于细胞的黏附.     

Cytokine-stimulated secretion of group II phospholipase A2 by rat mesangial cells. Its contribution to arachidonic acid release and prostaglandin synthesis by cultured rat glomerular cells.

Potent pro-inflammatory cytokines, such as interleukin 1 (IL-1) or tumor necrosis factor (TNF) alpha have been found to increase group II phospholipase A2 (PLA2) synthesis and secretion by mesangial cells. In all cases 85-90% of the enzyme is secreted from the cells and a parallel increase in prostaglandin (PG)E2 synthesis is observed. We report here that co-incubation with a monoclonal antibody that specifically binds and neutralizes rat group II PLA2 attenuates IL-1 beta and TNF alpha-stimulated PGE2 production by 45% and 52%, respectively. CGP43182, a specific inhibitor of group II PLA2, potently blocks mesangial cell group II PLA2 in vitro with a half-maximal inhibitory concentration (IC50) of 1.5 microM, while only slightly affecting mesangial cell high molecular weight PLA2. CGP 43182 markedly attenuates IL-1 beta- and TNF alpha-stimulated PGE2 synthesis in intact mesangial cells with IC50's of 1.3 and 1.0 microM, respectively. PLA2 secreted from cytokine-stimulated mesangial cells was purified to homogeneity. Addition of the purified enzyme to unstimulated mesangial cells causes a marked release of arachidonic acid and a subsequent increased synthesis of PGE2. Moreover, addition of purified PLA2 to a cloned rat glomerular epithelial cell line and cultured bovine glomerular endothelial cells augmented both arachidonic acid release and PGE2 synthesis, with the endothelial cells being especially sensitive. Thus, cytokine-triggered synthesis and secretion of group II PLA2 by mesangial cells contributes, at least in part, to the observed synthesis of PGE2 that occurs in parallel to the enzyme secretion. Furthermore, extracellular PLA2 secreted by mesangial cells is able to stimulate arachidonic acid release and PGE2 synthesis by the adjacent endothelial and epithelial cells. These data suggest that expression and secretion of group II PLA2 triggered by pro-inflammatory cytokines may crucially participate in the pathogenesis of inflammatory processes within the glomerulus.     

聚乳酸膜等离子接枝聚合聚乙烯基 吡咯烷酮及表面性能研究

背景：由于聚乳酸表面亲水性差、缺乏天然分子识别位点等缺点而限制了其应用。通过复合、化学接枝等方法试图引进亲水性基团,但过程比较复杂,并应用大量有机试剂,影响材料的生物相容性。目的：利用低温等离子技术对聚乳酸进行表面改性,改善其亲水性。设计：对比观察。单位：暨南大学科学与工程系。材料：实验于 2004-10/2005-10 在广州人工器官和材料工程研究中心实验室完成。实验用主要材料：聚乳酸（Mr 29 000,山东医疗器械研究所）,乙烯基吡咯烷酮（美国 Acros 公司,使用前经重蒸纯化）。方法：通过改变不同的工作条件（功率=150 W,时间=3,2,l min;功率=30 W,t=10,8,5,3,l min） 选择优化条件,然后通过气相法和常压液相法进行 PLA-乙烯基吡咯烷酮接枝反应。主要观察指标：通过扫描电镜和原子力显微镜观察材料的表面形态;水接触角测量仪测定材料等离子处理和等离子接枝前后亲水性的变化;傅里叶变换红外光谱仪测定材料的结构变化;通过材料改性前后质量变化分析材料的接枝情况。结果：①扫描电镜显示等离子处理和接枝后的材料表面呈现大小不一的气孔和沟痕。②接枝后的水接触角由原来的 78°下降到 50°。③傅里叶变换红外光谱图表征1 750 cm-1吸收峰的低波数侧1 637.19 cm-1出现新的吸收峰,该峰对应于聚乙烯基吡咯烷酮链段上酰胺基团中的羰基伸缩振动吸收。④聚乳酸膜材料经低温等离子处理后,材料的质量变化百分数为-0.6。结论：等离子处理和接枝后材料的亲水性有明显变化,材料表面呈现大小不一的气孔和沟痕,此表面有利于细胞的黏附。     

Synthesis and properties of a temperature-sensitive hydrogel based on physical crosslinking via stereocomplexation of PLLA-PDLA

A synthetic route to amphiphilic conetwork (APCN) gels was developed and involved (1) a ring-opening polymerization (ROP) synthesis of the macromonomer HEMA-PLLA/PDLA, and (2) a radical polymerization of a stereocomplex of the synthesized macromonomers with P(MEO₂MA-co-OEGMA) to form the APCN gels. The structure of the gel was successfully verified using X-ray diffraction. Thermal analysis and differential scanning calorimetry data showed that the thermal behaviors of the gels were greatly improved compared with that of polylactic acid (PLA). The mechanical properties of the gels were measured by using a dynamic viscometer, and the results indicated a greater mechanical strength before swelling than afterwards, and an increasing strength of the gels with increasing amount of PLA stereocomplex. Gels placed in different aqueous phases at different temperatures showed different swelling ratio (SR) values. Specifically, the SR gradually decreased as the temperature was increased, indicating a temperature sensitivity of the gels. In addition, the gels placed in the aqueous and organic phases presented as hydrogels and hydrophobic gels, respectively, and their SR values were relatively low. These results indicated the amphiphilic nature of the gel, and indicated great application prospects for the gel in biomedicine.

A synthetic route to amphiphilic conetwork (APCN) gels was developed and involved (1) ring-opening polymerization synthesis of the macromonomer, and (2) radical polymerization of stereocomplex of the synthesized macromonomers with MEO₂MA, OEGMA to form the APCN gels.     

Humidity sensor based on poly(lactic acid)/PANI–ZnO composite electrospun fibers

The electrospinning technique has been successfully used to prepared micro-fibers of the poly(lactic acid)/polyaniline–zinc oxide (PLA/PANI–ZnO) composite. The polyaniline–zinc oxide (PANI–ZnO) nanocomposites are synthesized by hydrothermal and in situ polymerization methods. X-ray diffraction techniques are used to study the structural properties of the PLA/PANI–ZnO composite fibers and the PANI–ZnO nanocomposite. The average crystallite size of the PANI–ZnO nanocomposite is found to be 36 nm. The morphology and diameter of the composite fibers are analyzed by scanning electron microscopy (SEM). The average fiber diameter of the pure poly(lactic acid) (PLA) fiber is around 2.5 μm and that of the PLA/PANI–ZnO composite fiber is around 1.4 μm. Differential scanning calorimetry (DSC) provides the thermal properties of the PLA/PANI–ZnO composite fibers. The melting temperature (T_m) for the pure PLA is observed at 149.3 °C, and it is shifted to 153.0 °C for the PLA/PANI–ZnO composite fibers. The enhanced thermal properties of the composite fibers are due to the interaction between the polymer and the nanoparticles. The water contact angle measurements probe the surface hydrophilicity of the PLA/PANI–ZnO composite fibers. The role of the PANI–ZnO nanocomposite on the sensing behavior of PLA fibers has also been investigated. The humidity sensing properties of the composite fiber based sensor are studied in the relative humidity (RH) range of 20–90% RH. The experimental results show that the composite fiber exhibited good response (85 s) and recovery (120 s) times. These results indicate that the one-dimensional (1D) fiber structure enhances the humidity sensing properties.

The electrospinning technique has been successfully used to prepared micro-fibers of the poly(lactic acid)/polyaniline–zinc oxide (PLA/PANI–ZnO) composite for humidity sensor application.     

Three-dimensional crimped biodegradable poly(lactic acid) fibers prepared via melt spinning and controlled structural reorganization

Biodegradable three-dimensional crimped fibers were prepared by the side-by-side composite spinning of poly(lactic acid) (PLA) and low-melting point PLA (LM-PLA). The structural variation of the PLA/LM-PLA composite fibers during dry and wet heat treatment was explored systematically. It is shown that crystallization and disorientation were two key factors for the formation of the three-dimensional crimped structure of PLA/LM-PLA side-by-side composite fibers (SSCF). The wet heat-treated fiber has better crimp performance and fluffiness, and the crimp number, crimp ratio and crimp elasticity ratio of the treated PLA/LM-PLA SSCF with good comprehensive properties are 21 per 25 mm, 31.9% and 81.6%, which are similar to those of industrialized PET/PTT three-dimensional crimped fibers. The results of this study shed light on the development of novel three-dimensional crimped fibers with biodegradability.

Biodegradable three-dimensional crimped Poly(Lactide acid)(PLA)/low-melt point poly(Lactide acid) (LM-PLA) side-by-side composite fiber was prepared by regulating the crystallization and disorientation through dry and wet heat treatment.     

A predictive model for the clearance of soluble phospholipase A2 during septic shock

Circulating phospholipase A2 (PLA2) has been recognized as a mediator of cardiovascular collapse in septic shock. Proximal mediators of endotoxemia, including tumor necrosis factor and interleukin 1, induce PLA2 synthesis and release, but the factors regulating PLA2 elimination are unknown. Similarly, the kinetics of PLA2 clearance during recovery from septic shock have not been examined. An autoregressive mathematical model was developed to describe the rate of PLA2 clearance during the recovery phase of septic shock. This model (which estimates that the current day's PLA2 level is 77% of the previous day's level), accounted for 89% of the variability seen in the data. The estimated circulating half-life of soluble PLA2 in septic shock in man was 32 hours. Since elevation in serum PLA2 activity is closely associated with bacteremia or endotoxemia, a significant deviation from predicted PLA2 values may denote impending relapse.     

Super tough poly(lactic acid) blends: a comprehensive review

Poly(lactic acid) or poly(lactide) (PLA) is a renewable, bio-based, and biodegradable aliphatic thermoplastic polyester that is considered a promising alternative to petrochemical-derived polymers in a wide range of commodity and engineering applications. However, PLA is inherently brittle, with less than 10% elongation at break and a relatively poor impact strength, which limit its use in some specific areas. Therefore, enhancing the toughness of PLA has been widely explored in academic and industrial fields over the last two decades. This work aims to summarize and organize the current development in super tough PLA fabricated via polymer blending. The miscibility and compatibility of PLA-based blends, and the methods and approaches for compatibilized PLA blends are briefly discussed. Recent advances in PLA modified with various polymers for improving the toughness of PLA are also summarized and elucidated systematically in this review. Various polymers used in toughening PLA are discussed and organized: elastomers, such as petroleum-based traditional polyurethanes (PUs), bio-based elastomers, and biodegradable polyester elastomers; glycidyl ester compatibilizers and their copolymers/elastomers, such as poly(ethylene-co-glycidyl methacrylate) (EGMA), poly(ethylene-n-butylene-acrylate-co-glycidyl methacrylate) (EBA-GMA); rubber; petroleum-based traditional plastics, such as PE and PP; and various biodegradable polymers, such as poly(butylene adipate-co-terephthalate) (PBAT), polycaprolactone (PCL), poly(butylene succinate) (PBS), and natural macromolecules, especially starch. The high tensile toughness and high impact strength of PLA-based blends are briefly outlined, while the super tough PLA-based blends with impact strength exceeding 50 kJ m⁻² are elucidated in detail. The toughening strategies and approaches of PLA based super tough blends are summarized and analyzed. The relationship of the properties of PLA-based blends and their morphological parameters, including particle size, interparticle distance, and phase morphologies, are presented.

PLA is a renewable, bio-based, and biodegradable aliphatic thermoplastic polyester that is considered a promising alternative to petrochemical-derived polymers in a wide range of commodity and engineering applications.