An investigation of melt rheology and thermal stability of poly(lactic acid)/ poly(butylene succinate) nanocomposites

A systematic investigation of the rheological and thermal properties of nanocomposites prepared with poly(lactic acid) (PLA), poly(butylene succinate) (PBS), and organically modified layered silicate was carried out. PLA/PBS/Cloisite 30BX (organically modified MMT) clay nanocomposites were prepared by using simple melt extrusion process. Composition of PLA and PBS polymers were fixed at a ratio of 80 to 20 by wt % for all the nanocomposites. Rheological investigations showed that high clay (> 3 wt %) contents strongly improved the viscoelastic behavior of the nanocomposites. Percolation threshold region was attained between 3 and 5 wt % of clay loadings. With the addition of clay content for these nanocomposites, liquid‐like behavior of PLA/PBS blend gradually changed to solid‐like behavior as shown by dynamic rheology. Steady shear showed that shear viscosity for the nanocomposites decreased with increasing shear rates, exhibiting shear‐thinning non‐Newtonian behavior. At higher clay concentrations, pseudo‐plastic behavior was dominant, whereas pure blend showed almost Newtonian behavior. Thermogravimetric analysis revealed that both initial degradation temperature (at a 2% weight loss) and activation energy of thermal decomposition nanocomposite containing 3 wt % of C30BX were superior to those of other nanocomposites as well as to those of PLA/PBS blend. Nanocomposite having 1 wt % of C30BX did not achieve expected level of thermal stability due to the thermal instability of the surfactant present in the organoclay. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Tailored biodegradable films via extrusion blow molding using PBS,PBAT, and TPS

Research to replace synthetic polymers with biodegradable polymers is on the rise because common plastics have generated serious ecosystem problems. Films with thermoplastic starch (TPS), poly(butylene succinate) (PBS), poly(butylene adipate-co-butylene terephthalate (PBAT), and citric acid (CA) were produced by blown extrusion. They were characterized by blow-up ratio (BUR), water vapor permeability (WVP), soluble ratio (SR), water sorption isotherm, and thermogravimetric (TG) techniques. Films were uniform and showed BUR > 205%. The different proportions of PBS and PBAT significantly influenced the WVP of the films. All samples had WVP with an order of magnitude similar to other blends with high starch content (10⁻⁶ g m⁻¹ day⁻¹ Pa⁻¹). CA efficiently decreased the WVP of the PBS/PBAT/TPS formulations (15/15/70% and 20/10/70% by mass) by 25.2% and 24.7% compared to the acid-free formulations. There was no significant difference in SR (19.0%–20.1%). These materials were sensitive to moisture since the equilibrium moisture content increased pronouncedly from water activity of 0.5. Films showed good thermal stability, with a maximum decomposition temperature close to pure polyesters. CA did not increase the thermal stability of blends, probably because of the low content used (0.1%). Given the outcomes of this study, these films could be deemed appropriate for applications in food packaging.     

Preparation and property testing of polymer blends of poly(lactic acid) and poly(butylene succinate) plasticised with long-chain fatty acids

This study investigates the influence of three fatty acids (lauric acid, palmitic acid, and stearic acid) on biodegradable polymer blends based on poly(lactic acid) (PLA) and poly(butylene succinate) (PBS), containing different weight ratios (100:0, 100:2, and 100:4) of fatty acids on the transparency, mechanical properties, morphology, contact angle, and water vapour permeability. All of the blends were pressed into thin films and tested. The experimental results showed that the properties of the samples varied with chain length and amounts of the fatty acids. Thus, it could be concluded that use of fatty acids opens up new ways for the plasticisation of PLA/PBS blends for use as new bioplastics.     

Fabrication of micelles from poly(butylene succinate) and poly(2‐methacryloyloxyethyl phosphorylcholine) copolymers as a potential drug carrier

A series of copolymers of poly(2‐methacryloyloxyethyl phosphorylcholine)‐b‐poly(butylene succinate)‐b‐poly(2‐methacryloyloxyethyl phosphorylcholine) (PMPC‐b‐PBS‐b‐PMPC) were synthesized by atom transfer radical polymerization. The structure of the polymers was characterized by ¹H NMR and infrared spectroscopy, and their thermal properties were described using TGA and DSC. In aqueous solutions, the PMPC‐b‐PBS‐b‐PMPC could form micelles with sizes ranging from 108 to 170 nm. In vitro release studies showed that acidic media and a longer PMPC chain benefited doxorubicin (DOX) release. 3‐(4,5‐dimethylthiazol‐2‐yl)‐2,5‐diphenyltetrazolium bromide (MTT) assays indicated that the micelles had low cytotoxicity to HeLa and L929 cells. DOX‐loaded micelles exhibited high cytotoxicity to HeLa cells. Flow cytometry results demonstrated that DOX‐loaded micelles could be internalized by HeLa cells. The in vitro phagocytosis results showed 3.9‐fold and 5.5‐fold reductions compared with poly(lactic acid) (PLA) nanoparticles and PDS55 micelles. These results demonstrate that PMPC‐b‐PBS‐b‐PMPC block copolymer micelles have great promise for cancer therapy. © 2017 Society of Chemical Industry     

拉伸形变作用下PLA/PBS增韧共混物力学性能研究

通过叶片挤出机对聚乳酸/聚丁二酸丁二醇酯（PLA/PBS）及添加剂进行塑化共混后制备复合增韧体系,研究不同PLA/PBS配比、挤出机转速以及添加剂种类对共混物力学性能的影响。结果表明,随着PBS含量的增加,PLA/PBS共混物的拉伸强度变化不大,而韧性明显提高;当叶片挤出机转速为75 r/min,改性剂邻苯二甲酸二仲辛酯(DCP)含量为0.05 %(质量分数,下同),马来酸酐接枝聚丙烯（PP-g-MAH)含量为1.5 %时,共混物具有最佳力学性能;PLA与PBS相容性较差,但叶片挤出机提供的拉伸力场迫使分散相分散均匀,尺度较小。     

金属离子对脂肪族聚酯降解性能的影响

在土壤培养液中添加不同种类的金属离子,研究了它们对可生物降解聚酯聚乳酸（PLA）、聚丁二酸丁二酯（PBS）膜降解性能的影响。采用傅里叶变换红外光谱仪表征了PLA和PBS膜降解前后的化学结构。结果表明：所有降解后的膜表面均有明显被侵蚀的痕迹;在土壤培养液中的Mg^2＋,Zn^2＋,Ca^2＋对PLA的降解性能有促进作用,对PBS的降解性能则影响不大;降解后PLA膜的玻璃化转变温度有所升高,但PBS膜变化不大。     

Phase behavior and morphology in blends of poly(L‐lactic acid) and poly(butylene succinate)

Blends of poly(L ‐lactic acid) (PLA) and poly(butylene succinate) (PBS) were prepared with various compositions by a melt‐mixing method and the phase behavior, miscibility, and morphology were investigated using differential scanning calorimetry, wide‐angle X‐ray diffraction, small‐angle X‐ray scattering techniques, and polarized optical microscopy. The blend system exhibited a single glass transition over the entire composition range and its temperature decreased with an increasing weight fraction of the PBS component, but this depression was not significantly large. The DSC thermograms showed two distinct melting peaks over the entire composition range, indicating that these materials was classified as semicrystalline/semicrystalline blends. A depression of the equilibrium melting point of the PLA component was observed and the interaction parameter between PLA and PBS showed a negative value of ?0.15, which was derived using the Flory–Huggins equation. Small‐angle X‐ray scattering revealed that, in the blend system, the PBS component was expelled out of the interlamellar regions of PLA, which led to a significant decrease of a long‐period, amorphous layer thickness of PLA. For more than a 40% PBS content, significant crystallization‐induced phase separation was observed by polarized optical microscopy. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 647–655, 2002     

阻燃聚丁二酸丁二醇酯复合材料的制备及其阻燃性能研究

采用熔融共混技术,将次磷酸铝(AHP)和三聚氰胺氰尿酸盐(MC)引入聚丁二酸丁二醇酯(PBS),制备了一系列阻燃PBS复合材料,并采用极限氧指数、垂直燃烧、微型量热测试以及热失重分析研究了复合材料的阻燃性能以及热稳定性。结果表明,AHP可以有效提高PBS复合材料的阻燃性能;AHP与MC复配可以进一步提高复合材料的阻燃性能,两者质量比为2∶1,添加量为20 %（质量分数,下同）即可使复合材料达到UL 94 V 0级别,极限氧指数达到29 %;AHP以及复合阻燃体系可以有效提高复合材料初始分解温度及其高温稳定性。     

增容剂DT对PLA/PBAT共混物性能的影响

以不饱和酯类化合物(DT)为增容剂,通过双螺杆挤出机反应性挤出制备聚乳酸(PLA)/聚己二酸对苯二甲酸丁二酯(PBAT)共混物。采用扫描电子显微镜、旋转流变仪、偏光显微镜、差示扫描量热仪、热重分析仪和万能试验机讨论DT对共混物相容性、结晶性能、热失重以及力学性能的影响。结果表明,适量的DT增加了两相之间界面黏结,有效改善了PLA和PBAT之间相容性;当DT添加量为0.3 %（质量分数,下同）时,断裂伸长率增加了46.3 %,冲击强度显著增加,冲击试样未完全断裂。     

PLA/PBAT共混物的降解性能研究

通过双螺杆挤出机和吹膜机组制备不同比例的聚乳酸/聚对苯二甲酸己二酸丁二酯（PLA/PBAT）共混物薄膜,测量共混物的热性能、力学性能,并观察其相形貌,计算共混物在堆肥条件下的生物降解率,研究共混物降解前后的结构、热力学行为和元素的变化。结果表明,PLA与PBAT是不相容体系,加入PBAT后PLA的韧性得到改善;PLA的生物降解率高于PBAT,共混物的生物降解率随着PBAT含量的增加而降低,且在降解初期,PLA的降解产物会促进PBAT的水解;PLA、PBAT及其共混物在堆肥降解前期只是大分子链水解为小分子链的过程,不发生分子链的结构变化;PLA及PBAT的降解会先发生在无定形区,共混物中PLA在无定形区的降解速度受到PBAT的影响而变慢,且共混物中PLA、PBAT的降解行为发生变化,无定形区与结晶区的降解同时发生;共混物在堆肥试验初期的降解以水解为主。     

生物可降解共聚物PBST和PBS的结构与结晶性能

利用核磁共振氢谱和广角X射线衍射法研究了生物可降解共聚物聚对苯二甲酸-共-丁二酸丁二醇酯(PBST)的结构及结晶性能,并与聚丁二酸丁二醇酯(PBS)进行比较。结果表明:PBST为无规共聚物,其晶体结构为三斜晶系,PBS为均聚物,为单斜晶系,PBST的结晶度和结晶尺寸均比PBS的小。     

High performance materials based on a self‐assembled multiple‐percolated ternary blend

In this study, it will be shown that morphologically tailored tricontinuous ternary blends, comprising polybutylene succinate (PBS), polylactic acid (PLA), and poly (butylene adipate‐co‐terephthalate)(PBAT), can generate new materials with excellent properties. Detailed morphological analysis is used to establish that all three phases in the ternary 33%PBS/33%PLA/33%PBAT blend morphology are highly continuous with a phase structure dominated by complete wetting dynamics. PBS is shown to situate itself between PLA and PBAT. This melt processed, self‐assembled, multiple percolated, blend possesses a high elongation at break (567%), high Young's modulus (1130 MPa), high impact strength (271 J/m), and a storage modulus about 50% higher than pure PBS at room temperature. None of the neat materials demonstrate this combination of high properties and the synergy derives from the tricontinuous structure of the system. The ternary nature of the blend allows for a modulation of the crystallinity behavior as examined by differential scanning calorimeter and X‐ray Diffraction. © 2014 American Institute of Chemical Engineers AIChE J, 60: 3005–3012, 2014     

聚乳酸／PBAT共混物的制备及其性能研究

用熔融挤出法制备了聚乳酸饼苯二甲酸-己二酸-1，4-丁二醇三元共聚酯（PLA／PBAT）共混物，研究了聚乳酸／PBAT共混物的力学性能、热性能以及相容性。结果表明：共混物的冲击强度及断裂伸长率随着PRAT含量的增加而增大，在PBAT含量为30％时，断裂伸长率最大，达到9％，PBAT的加入降低了共混物的拉伸、弯曲性能，但在添加量较少的情况下（如5％和10％），拉伸、弯曲性能下降不大。退火处理极大的提高了材料的维卡软化温度。当PBAT含量较高时，共混物的断面可以明显的观察到不相容的两相结构。     

熔融扩链反应制备PLA／PBAT多嵌段共聚物

以六亚甲基二异氰酸酯(HDI)为扩链剂,在催化剂辛酸亚锡作用下,通过熔融扩链反应制备了聚乳酸(PLA)/聚(己二酸丁二酯/对苯二甲酸丁二酯)(PBAT)多嵌段共聚物.研究了反应时间、温度、扩链剂用量等工艺条件对PLA/PBAT共聚物结构、相对分子质量的影响.用红外光谱仪、核磁共振仪、偏光显微镜等分析手段对PLA、PBAT和PLA/PBAT共聚物进行了分析表征.结果表明,通过扩链反应,PLA的分子链中引入了新的嵌段,其相时分子质量及柔韧性大幅度提高.     

P3/4HB/PBS共混物的物理性能及微生物降解

将不同比例的聚(3-羟基丁酸-co-4-羟基丁酸)共聚酯(P3/4HB)和聚丁二酸丁二酯(PBS)进行物理共混,通过FTIR、DSC、TG和SEM研究了复合材料的力学性能、亲水性能、热稳定性和结晶性。当PBS的添加量为10%时,复合材料的力学性能较好。与纯P3/4HB相比,拉伸强度增加了154%,达到了18.6 MPa;断裂伸长率增加了82%,为638%;弹性模量约下降94 MPa。复合物水溶解性能较小,只有0.34%,抗水性增强。DSC分析表明,2种聚合物的相容性较好。PBS的添加降低了材料的熔点,增加了结晶性能,同时减缓了材料的结晶速率。TG分析结果表明,复合材料稳定性增强,加工窗口拓宽了32℃。采用Pseudomonas.mendocina DS04-T菌株降解复合材料,当降解时间为120 h时,复合材料降解率为92.5%。     

聚丁二酸丁二醇酯的扩链改性及共混研究

采用扩链剂2,4-甲苯二异氰酸酯（TDI）、2,2′-双（2-恶唑啉）（BOZ）以及新型扩链剂ADR-4370对聚丁二酸丁二醇酯（PBS）进行扩链,对比研究3种扩链剂对PBS性能的影响。采用聚乳酸（PLA）与PBS共混,选择最佳配比以及合适的共混工艺。结果表明,新型扩链剂ADR-4370可以良好的改善PBS的加工性能和机械性能,m（PBS）/m（PLA）最佳配比为70：30,在共混同时进行扩链比扩链后再共混可以更好的提高PBS/PLA的性能。     

PBT共混改性研究最新进展

综述了最近几年国内外聚对苯二甲酸丁二醇酯(PBT)共混改性的研究进展,分类介绍PBT/聚烯烃、PBT/同系聚酯、PBT/液晶、PBT/弹性体、PBT/聚碳酸酯等不同共混体系,讨论了各体系中的相行为、相容性、热稳定性、力学性能等,并对该类共混物的发展趋势作了简要的分析。     

The effect of poly(butylene succinate) content on the structure and thermal and mechanical properties of its blends with polylactide

Poly(butylene succinate) (PBS) and polylactide (PLA) were blended in a co‐rotating twin‐screw extruder with various contents of PBS from 0 to 100 wt%. The effect of PBS content on the thermal and mechanical properties of PBS/PLA blends was investigated by using DSC, softening point measurements, a Charpy impact test and tensile testing. The Fourier transform infrared spectra showed that the polymers are immiscible, but the addition of PBS could modify the PLA structure in PBS/PLA blends by changing the content of amorphous and crystalline phases. In addition, the cold crystallization temperature of PLA in blends decreases in comparison with pure PLA, which shows that PBS could have a plasticizing effect on PLA. This is confirmed by the results of DSC analysis. The mechanical properties of the blends depend on the percentage of PBS addition. Typically, the mechanical properties of PBS/PLA blends are intermediate between the properties of the polyesters from which they are obtained. However, in some cases unexpected changes in mechanical properties of the blends were observed. For example, the elongation at break for a PBS/PLA blend containing 10 wt% PLA is higher than for pure PBS. © 2019 Society of Chemical Industry     

脂肪族聚酯降解材料的研究进展

本文对脂肪族聚酯类生物降解材料聚乳酸(PLA)、聚己内酯(PCL)、聚羟基烷酸酯(PHAs)、聚丁二酸丁二醇酯(PBS)等进行了简单的综述,简要地介绍了其主要应用领域及存在的主要问题。     

聚乳酸/聚(已二酸-对苯二甲酸丁二酯)共混物的非等温结晶动力学

采用熔融挤出法制备了聚乳酸/聚(已二酸-对苯二甲酸丁二酯)共混物。利用差示扫描量热仪研究了聚乳酸及其共混体系的非等温结晶过程。用经Jeziorny修正的Avrami方程和Mo法对其非等温结晶动力学进行了分析。结果表明:Avrami方程和Mo法都适用于处理聚乳酸及其共混体系的非等温结晶过程,共混物的结晶速率大于聚乳酸的结晶速率。此外,用Huffman-Lauritzen理论计算了非等温结晶的结晶活化能,发现共混体系的结晶活化能绝对值小于聚乳酸。