生物塑料聚(3-羟基丁酸酯-co-4-羟基丁酸酯)改性研究

文章介绍了生物塑料聚(3-羟基丁酸酯-co-4-羟基丁酸酯)(P3/4HB)的性能;综述了针对P3/4HB加工成型温度窄、产品脆性大、应用成本高等缺点而进行的物理改性、化学改性等技术进展;提出了对P3/4HB发展过程中需要解决的问题;同时指出P3/4HB的研究将集中在其材料结晶性能、加工流动性改善的发展方向。     

聚(3-羟基丁酸酯-co-4-羟基丁酸酯)研究进展

介绍了生物可降解材料聚(3-羟基丁酸酯-co-4-羟基丁酸酯)(P(3HB-co-4HB))的性能及特点;综述了针对P(3HB-co-4HB)加工温度窄、脆性大、成本高等缺点而进行的增塑改性、扩链改性、共混改性的技术进展以及P(3HB-co-4HB)纺丝成纤技术;阐述了利用P(3HB-co-4HB)可塑性、生物降解性和生物相容性等在医疗领域的应用情况及发展前景;指出P(3HB-co-4HB)的研究将集中在其材料加工流动性、结晶性能的改善及其纤维加工技术与纤维表面整理技术等方面。     

聚(3-羟基丁酸酯-co-4-羟基丁酸酯)的扩链改性

采用环氧丙烯酸型扩链剂改性聚(3-羟基丁酸酯-co-4-羟基丁酸酯)[P(3HB-co-4HB)],考察了扩链剂对熔体黏弹性、力学性能和成型发泡的影响.用流变仪测试熔体稳态黏度与剪切速率、动态黏弹模量与角频率、模量与时间的关系,用扫描电子显微镜观察改性前后P(3HB-co-4HB)的断面形貌.结果表明,扩链剂的加入提高...     

聚(3-羟基丁酸酯-co-4-羟基丁酸酯)/纳米氮化钛共混体系研究

采用熔融共混方法制备了聚(3-羟基丁酸酯-co-4-羟基丁酸酯) [P(3HB-co-4HB)]和纳米氮化钛(TiN)的复合体系,并通过万能材料试验机、差示扫描量热仪(DSC)、偏光显微镜(POM)、X射线衍射仪(XRD),热失重分析仪(TG)等测试手段考察了不同含量TiN对P(3HB-co-4HB)基体的力学、热力学及结晶性能的影响.结果表明:纳米氮化钛在共混体系中起到成核剂作用,可有效改善P(3HB-co-4HB)结品性能,提高其韧性.     

聚(3-羟基丁酸酯-co-4-羟基丁酸酯)的性能

采用毛细管流变仪、差示扫描量热仪、热失重分析仪及偏光显微镜(POM)研究了聚(3-羟基丁酸酯-co-4-羟基丁酸酯)[P(3HB-co-4HB)]的流变性能、热性能及结晶性能.P(3HB-co-4HB)熔体属于典型的假塑性流体,剪切应力与剪切速率关系符合Ostwald-de Wale幂率定律,熔体表观黏度与温度的关系符合Arrhenius方程;P(3HB-co-4HB)的玻璃化转变温度约为-10℃,熔点在100～120℃,降解温度约为205℃;POM观察发现,P(3HB-co-4HB)在约78℃时球晶半径径向生长速率最大.     

聚(3-羟基丁酸酯-co-4-羟基丁酸酯)/酰胺成核剂共混体系

采用熔融共混方法制备了聚(3-羟基丁酸酯-co-4 -羟基丁酸酯)[P( 3HB-co-4HB)]和酰胺成核剂的复合体系,并通过万能材料试验机、差示扫描量热仪( DSC)、偏光显微镜(POM)和X射线衍射仪(XRD)等测试手段考察了不同含量酰胺成核剂对P( 3HB-co-4HB)基体的力学、热力学及结晶性能的影响.结果表明:酰胺成核剂在共混体系中起到成核剂作用,可有效改善P(3 HB-co-4HB)结晶性能,提高其韧性.     

可生物降解聚(3-羟基丁酸酯-co-4-羟基丁酸酯）/层状?-磷酸锆纳米复合材料的制备及性能

以可生物降解聚（3-羟基丁酸酯-co-4-羟基丁酸酯）[P(3,4)HB]为基体,有机改性层状化合物?-磷酸锆（OZrP）为增强相,采用溶液插层法制备了P(3,4)HB/OZrP纳米复合材料。分别用X射线衍射仪（XRD）、扫描电镜（SEM）、偏光显微镜（POM）、热重分析仪（TGA）和差式扫描量热仪（DSC）等对其微观结构、热稳定性、结晶行为及降解性能进行了表征与分析。研究表明,具有纳米片层结构的OZrP能均匀分散在P(3,4)HB基体中形成纳米复合结构,OZrP能通过异相成核作用促进P(3,4)HB的结晶,并能促进P(3,4)HB的降解,但降低P(3,4)HB 的热稳定性。     

第四代PHA生物塑料聚3-羟基丁酸酯4-羟基丁酸酯

PHA具有很好的生物降解性能,随着聚羟基脂肪酸酯(PHA)的研究及发展,新一代全生物降解塑料聚3-羟基丁酸酯4-羟基丁酸酯(P3HB4HB)是一种综合性能优异的生物塑料,力学性能与通用塑料PP和PE相近,并可以在传统塑料加工设备上加工成型,新一代生物塑料问世较晚,相应的开发研究和应用还需进一步挖掘。     

聚乳酸/聚(3-羟基丁酸酯-co-4-羟基丁酸酯)/改性高岭土纳米复合材料的结晶、动态力学及流变行为

为提高聚乳酸(PLA)/聚(3-羟基丁酸酯-co-4-羟基丁酸酯)(P(3HB-co-4HB))基体的综合性能,采用熔融共混法制备聚乳酸/聚(3-羟基丁酸酯-co-4-羟基丁酸酯)/改性高岭土(modified kaolin)纳米复合材料。利用DSC、DMA、旋转流变仪、扫描电镜(SEM)等对复合体系的结晶、动态力学性能、流变行为、表面结构等进行了研究。结果表明:复合体系的冷结晶温度逐渐变小,降低了12.5℃,结晶能力有所提高。此外,结晶度由21.65%增加到35.22%,提高了62.68%。DMA结果显示,随着改性高岭土添加量的增多,复合体系的储能模量E′和玻璃化转变温度出现先增大后减小的变化。熔融态下,复合体系的黏度随剪切速率的增大而减小,属假塑性流体。当体系中改性高岭土添加量为4%时,材料的缺口冲击强度有明显的改善。利用SEM发现,少量改性高岭土可以均匀地分散在PLA/P(3HB-co-4HB)基体中并能显著提高复合体系的韧性。     

聚(3-羟基丁酸酯-共-4-羟基丁酸酯)/马来酸酐共混物性能的研究

采用熔融共混方法制备了一系列聚(3-羟基丁酸酯-共-4-羟基丁酸酯)/马来酸酐(MA)的共混物。研究了MA含量对共混物力学性能的影响,并且采用差示扫描量热仪和热失重分析仪对共混物热性能的变化进行了研究。结果表明,MA的加入有效改善了聚(3-羟基丁酸酯-共-4-羟基丁酸酯)的力学性能和热稳定性,拓宽了其加工窗口,其中加入0.5份MA就可将共混物的起始热分解温度提高19.31℃。同时,MA能够改善3-羟基丁酸酯微区和4-羟基丁酸酯微区的相容性。     

Difference in environmental degradability between poly(ethylene succinate) and poly(3-hydroxybutyrate)

A chemosynthetic aliphatic polyester, poly(ethylene succinate) (PESu), was degraded by a poly(3-hydroxybutyrate) (P(3HB)) depolymerase in vitro. While P(3HB) exhibited good biodegradability in all environments, PESu hardly underwent biodegradation in a marine environment. To understand the difference in environmental degradability between PESu and P(3HB), we investigated the distribution of P(3HB)- and PESu-degrading microbes in various environments. PESu-degrading microbes were never detected in marine environments. PESu-degrading bacteria isolated from various environments in this study belonged to the phyla Firmicutes and Proteobacteria. Most PESu-degrading bacterial isolates could not degrade P(3HB), suggesting that PESu was not degraded by P(3HB) depolymerase in actual environments. In addition, all bacterial isolates that were screened for P(3HB) degrading activity from various environments in this study did not degrade PESu, suggesting that PESu does not induce P(3HB) depolymerase in their bacteria and P(3HB)-degrading bacteria are not involved in biodegradation of PESu in actual environments. Taken together, these results could be related with the low biodegradability of PESu in marine environments.     

Microbial synthesis and properties of poly(3-hydroxybutyrate-co-4-hydroxybutyrate)

Microbial synthesis of copolymers of [R]-3-hydroxybutyrate (3HB) and 4-hydroxybutyrate (4HB), P(3HB-co-4HB), by Alcaligenes eutrophus, Alcaligenes latus, and Comamonas acidovorans from various carbon sources has been studied. The copolyester compositions varied from 0 to 100 mol% 4HB, depending on the microorganism and the combination of carbon substrates supplied. The thermal and physical properties of compositions with 0–100 mol% 4HB were investigated. The copolyesters represented a wide variety of polymeric materials, from hard crystalline plastic to very elastic rubbers, depending on composition. The copolyester films with high 4HB fractions (64–100 mol% 4HB) exhibited the characteristics of a thermoplastic elastomer, and the tensile strength increased from 17 to 104 MPa as the 4HB fraction increased. The enzymatic degradation of P(3HB-co-4HB) films was studied in an aqueous solution of extracellular polyhydroxybutyrate (PHB) depolymerase from Alcaligenes faecalis or lipase from Rhizopus delemer. The erosion rate of P(3HB-co-4HB) films was strongly dependent on the copolymer composition. In addition, environmental degradation of P(3HB-co-4HB) films in sea water was investigated.     

Controlled Delivery of Gentamicin Using Poly(3-hydroxybutyrate) Microspheres

Poly(3-hydroxybutyrate), P(3HB), produced from Bacillus cereus SPV using a simple glucose feeding strategy was used to fabricate P(3HB) microspheres using a solid-in-oil-water (s/o/w) technique. For this study, several parameters such as polymer concentration, surfactant and stirring rates were varied in order to determine their effect on microsphere characteristics. The average size of the microspheres was in the range of 2 μm to 1.54 μm with specific surface areas varying between 9.60 m(2)/g and 6.05 m(2)/g. Low stirring speed of 300 rpm produced slightly larger microspheres when compared to the smaller microspheres produced when the stirring velocity was increased to 800 rpm. The surface morphology of the microspheres after solvent evaporation appeared smooth when observed under SEM. Gentamicin was encapsulated within these P(3HB) microspheres and the release kinetics from the microspheres exhibiting the highest encapsulation efficiency, which was 48%, was investigated. The in vitro release of gentamicin was bimodal, an initial burst release was observed followed by a diffusion mediated sustained release. Biodegradable P(3HB) microspheres developed in this research has shown high potential to be used in various biomedical applications.     

Thermal stability of poly(3‐hydroxybutyrate‐co‐4‐hydroxybutyrate)/modified montmorillonite bio‐nanocomposites

Poly(3‐hydroxybutyrate‐co‐4‐hydroxybutyrate) (P34HB)/modified montmorillonite (EMMT) bio‐nanocomposites were prepared via melt intercalation method. The thermal stability of the bio‐nanocomposites was investigated. The results showed that the decomposition temperature (T _5%) of P34HB/EMMT bio‐nanocomposite reached 271.4°C, 39.9°C higher than that of pure P34HB. The remarkable thermal stability enhancement was presumably originated from the uniform dispersion of EMMT in the matrix and intercalated structures of P34HB/EMMT bio‐nanocomposites, which was related to the increased compatibility of EMMT and P34HB caused by the ester group in EMMT. TGA‐FTIR analysis on the thermal degradation procedures of the bio‐nanocomposites manifested that the introduction of EMMT did not alter the degradation mechanism of P34HB. However, the intercalated structures hindered the mobility of P34HB macromolecular and slowed down the decomposing process of P34HB. POLYM. COMPOS., 38:673–681, 2017. © 2015 Society of Plastics Engineers     

P34HB共混改性聚乳酸纤维柔软性能研究

将聚乳酸与聚3-羟基丁酸酯-4-羟基丁酸酯共聚物(P34HB)按一定比例进行共混,再用熔融纺丝的方法制备聚乳酸共混纤维,通过扫描电镜、X射线衍射仪、织物风格仪等对纤维的结晶取向、相容性、力学性能、手感等进行了研究。结果表明:随着P34HB含量增加,共混纤维的断裂强度下降,断裂伸长率变大,分子链的取向度、动态弹性模量降低;但P34HB的加入,能大大改善织物的表面粗糙度,特别在P34HB质量分数为40%的时候,共混织物表面粗糙度为3.07μm,表面光滑;并且该比例的织物易剪切变形,剪切回复力好,能轻松错动。     

Effect of zinc borate on the fire and thermal degradation behaviors of a poly(3-hydroxybutyrate-co-4-hydroxybutyrate)-containing intumescent flame retardant

The aim of this study was to investigate the effect of zinc borate (ZnB) on the fire and thermal degradation behaviors of a poly(3-hydroxybutyrate-co-4-hydroxybutyrate) [P(3,4)HB]-containing intumescent flame retardant (IFR). The IFR system was composed of ammonium polyphosphate, pentaerythritol, and melamine. The fire properties of P(3,4)HB/IFR/ZnB blends were evaluated by limited oxygen index, Underwriters Laboratories 94, microscale combustion calorimetry (MCC), and cone calorimetry (CONE) testing. The results of MCC and CONE show that the peak heat release rate, which is an important indicator of material fire hazard, of P(3,4)HB/IFR decreased when a small amount of the IFR was substituted by ZnB. The thermal degradation behavior of the P(3,4)HB/IFR/ZnB blends were measured by thermogravimetric analysis and thermogravimetric analysis–infrared (TG–IR) spectrometry. The data of TG–IR showed that the flammable gas products of P(3,4)HB released during the thermal degradation process were greatly decreased. Scanning electron microscopy analysis revealed that more compact char residues were observed with the incorporation of ZnB. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

P34 HB/木粉生物复合材料降解过程中结构与性能的变化

以毛白杨木粉(WF)和聚(3-羟基丁酸酯-co- 4-羟基丁酸酯)(P34HB)为原料,采用共混热压法制备P34HB/木粉生物复合材料。利用电子扫描显微镜(SEM)、差示扫描量热法(DSC)、热重(TG)分析、力学试验机等研究了生物复合材料自然降解过程中的结构、力学性能及热稳定性的变化。结果表明：复合材料降解前期主要是P34HB基体的降解,其后木粉纤维开始降解,降解过后的P34HB基体呈现蜂窝状。复合材料的质量损失随着时间的增加呈现上升趋势,降解100天后复合材料的质量下降了34.43%。TG和DSC进一步表明复合材料最开始降解的主要是P34HB基体,后期开始伴随有木粉纤维的降解。复合材料的弯曲强度和杨氏模量随降解时间的增加呈下降趋势,降解前10天弯曲强度和杨氏模量下降较快,分别从24.67和2 768.25 MPa下降到16.72和1 339.34 MPa,下降率为32.23%和51.62%,随后下降速率减慢,降解80天后复合材料的弯曲强度和杨氏模量达到6.74和469.43 MPa,分别下降了72.68%和83.04%,之后趋于平衡。     

Novel Poly(3-hydroxyoctanoate)/Poly(3-hydroxybutyrate) blends for medical applications

Novel Poly(3-hydroxybutyrate)/Poly(3-hydroxyoctanoate) blends were developed with varying amounts of Poly(3-hydroxyoctanoate), P(3HO) and Poly(3-hydroxybutyrate), P(3HB) for their potential use in various medical applications. These blend films exhibited higher tensile strength and Young’s modulus values compared to neat P(3HO). The overall protein adsorption and % cell viability was also found to be significantly higher in the blend films than the neat P(3HO) film. Hydrolytic degradation was faster in the blend films and the degradation rate could potentially be tailored to achieve the optimum rate required for a particular medical application. Hence, these novel blends were found to be highly biocompatible with surface, mechanical and thermal properties suitable for a range of potential medical applications, a great step forward in the area of medical materials.