聚对苯二甲酸-己二酸丁二酯/聚3-羟基丁酸酯4-羟基丁酸酯共混材料的制备及性能表征

采用熔融共混制备了聚对苯二甲酸-己二酸丁二酯(poly(butylene adipate-co-terephthalate),PBAT)与聚3-羟基丁酸酯4-羟基丁酸酯(poly(3-hydroxybutyrate-co-4-hydroxybutyrate),P34HB)的共混材料。研究了P34HB含量(0 wt%, 5 wt%、 10 wt%、 15 wt%、 20 wt%)对共混材料熔体流动性能、力学性能、热性能和界面微观形貌的影响,及其PBAT/P34HB吹塑薄膜的力学性能和氧气阻隔性能。结果表明,P34HB的加入降低了材料的熔体黏度,提高了材料的流动性以及薄膜的直角撕裂性能、穿刺性能和氧气阻隔性能。当P34HB含量为5wt%时,共混材料综合性能最佳,两相相容性良好,共混材料和吹塑薄膜均具有优异的力学性能,薄膜的拉伸性能和穿刺强度最高,是性能优异的包装和农膜材料。     

α-环糊精与聚己二酸乙二醇酯的包合物对聚己二酸乙二醇酯结晶性能的影响

制备了聚己二酸乙二醇酯（PEA）与α-环糊精（α-CD）的包合物（PEAIC）,用红外光谱、核磁共振氢谱和X射线衍射对产物的结构进行了表征,并用差示扫描量热仪和偏光显微镜研究了PEAIC对PEA结晶的影响。结果表明：PEA可以和α-CD发生非共价键作用,形成隧道状晶体结构;同时PEAIC的加入,提高了PEA的结晶温度,...     

聚丁二酸丁二酯的无卤阻燃性能的研究

本文研究了聚苯基膦酸二苯砜酯(PSPPP)对聚丁二酸丁二酯(PBS)的阻燃作用。研究发现,在PBS中仅添加4wt%的PSPPP,其垂直燃烧就可以达到UL-94 V-0级,极限氧指数达到34,PSPPP对PBS表现出高效阻燃作用。然而,PSPPP对PBS有促进降解的作用,破坏了PBS的力学性能。通过在PBS/PSPPP体系中添加0.5wt%氧化锌后,有效抑制了PBS的降解,力学性能得到改善。     

聚富马酸丁二酯的水热老化行为研究

研究了聚富马酸丁二酯(PBF)的水热老化行为,采用凝胶渗透色谱法(GPC)、力学性能测试,示差扫描量热法(DSC)和全反射红外光谱(ATR-FTIR)研究了老化过程中PBF的分子量、力学性能、热性能和表面化学基团含量的变化.研究结果表明,PBF在30℃下具有良好的耐老化性能.温度对PBF老化行为的影响显著,水热老化温度升至60℃,PBF各项力学性能急剧下降,老化20天后样品在水中断裂并形成碎片,力学性能完全丧失,同时数均分子量下降了50%.80℃水热老化5天,样品即断裂并形成碎片,失去结构的完整性,数均分子量下降了87%.老化过程中碳碳双键的含量未发生明显变化,老化降解的机理是水的增塑、溶胀以及酯键水解,聚合物分子链断裂,分子量下降.     

聚琥珀酸丁二酯的辐射交联及其生物降解性

对聚琥珀酸丁二酯（PBS1）采用两步法辐照，比其它辐照法得到的凝胶含量高，这是由于在室温下预先辐射所形成的交联网络结构减少了聚合物的降解。交联后的PBS1有较高的耐热变形性。通过酶降解试验和土需求量法降解实验，PBS1有很高的生物降解性，即使它产生了很高的交联结构。在65℃时，酶的降解率最高。由于交联样品所含有的交联网络结构阻碍它的降解，交联PBS1的生物降解失重低于未交联样品。     

真菌BFM-X1对聚丁二酸丁二醇酯薄膜的降解过程

对菌株Bionectria sp.BFM-X1(简称BFM-X1)分别利用不同碳源对聚丁二酸丁二醇酯(PBS)薄膜的降解情况及降解后的残留膜进行了观察分析,揭示PBS薄膜的微生物降解过程.结果表明:菌株分别以PBS乳剂、葡萄糖、大豆油及甘油为唯一碳源时均能有效降解PBS薄膜;降解过程表现为表面失去光泽期、裂纹状结构期、破碎期和完全降解期4个阶段,并存在迟滞期,且葡萄糖碳源下的降解速率快于其他碳源的;菌株的菌丝能在PBS膜表面上扩展生长是该菌株降解PBS的前提,真菌的寄生作用是前期降解的主要动力;降解过程中胞外酶的水解作用使聚合物的酯键水解,生成可被菌株同化吸收的小分子;菌株BFM-X1对PBS薄膜的降解首先发生在膜表面,非结晶部分先于结晶部分被降解.     

聚丁二酸丁二醇酯在堆肥条件下的生物降解性能研究

根据ISO 14855的检测方法,研究了聚丁二酸丁二醇酯(PBS)在堆肥条件下的生物降解性能,结果 表明PBS具有良好的生物降解性,且其形态对其降解速率有显著的影响,降解速率:PBS粉末>PBS片>PBS 颗粒。对堆肥中的微生物进行分离鉴定,在所选堆肥中主要分离出四种菌株:杂色曲霉菌、青霉菌、芽包杆菌 和直杆高温多孢菌,它们对PBS的降解能力各不相同,其中最有效降解PBS的菌株是杂色曲霉菌。     

生物降解PBS聚醋的改性研究进展

聚丁二酸丁二醇酯(PBS)是一种具有良好生物降解性的聚酯,本文简述了PBS的基础物性和力学性能,综述了各种改善PBS生物降解性、生物相容性、热学和力学性能的方法,重点介绍了通过共聚、共混等方法对PBS进行改性的研究进展.     

聚琥珀酸丁二酯的辐射交联和它的热变形行为

近年来 ,塑料废弃物污染环境的问题日趋严重 .对于环境的关心 ,已经使越来越多的科研人员对于研究环境友好化合物的发展产生了极大的兴趣 .发达国家先后制订了限制或禁止某些场合使用非降解性塑料 ,因此 ,多种可生物降解性塑料已经发展起来 .目前已经商业化的可生物降解性聚合物主要有脂肪族聚酯、聚醚、聚乙烯醇和聚多糖 .其中 ,利用化学合成法开发的可生物降解性聚合物是非常重要的 .脂肪族聚酯 ,例如聚乳酸(ＰＬＡ) .聚乙二酸 (ＰＧＡ)等被广泛地用于药物的载体[1] ,聚 (ε 己内酯 ) (ＰＣＬ)也已经被用作生产生物降解性薄膜 .脂肪族聚酯…     

乙酸稀土盐催化缩聚合成聚(对苯二甲酸乙二酯-co-己二酸乙二酯)

合成了一系列乙酸稀土盐(乙酸钇,乙酸镧,乙酸钕,乙酸镝),作为单组分催化剂,采用熔融缩聚法催化对苯二甲酸二甲酯、乙二醇和1,6-己二酸的共缩聚反应,制备了芳香族脂肪族共聚酯——聚(对苯二甲酸乙二酯-co-己二酸乙二酯)(PETA).通过1H-NMR,SEC,DSC及力学性能测试表征了聚合物的序列结构,分子量及分布,热性能及机械性能.结果表明,乙酸稀土盐单组分可催化共缩聚反应,效果优良,能够合成高分子量和较窄分子量分布的共聚酯,共聚酯具有较高的拉伸强度和断裂伸长率.     

Influence of Teflon Substrate on Crystallization and Enzymatic Degradation of Polymorphic Poly（butylene adipate）

Oriented and non-oriented Teflon films, which were found to have the same crystalline structure, but different surface morphologies, were used to sandwich poly(butylene adipate)(PBA) films during isothermal crystallization. It was found that both the Teflon surface structure and the PBA polymorphic structure are the determining factors to induce epitaxial crystallization. The oriented Teflon film was able to induce epitaxial crystallization of PBA α crystal, while the non-oriented Teflon did not induce any epitaxial crystallization of PBA. Epitaxial crystallization did not occurred for PBA β crystals between neither the oriented nor the non-oriented Teflon films. The enzymatic degradation rate of PBA films was not determined by the epitaxial crystallization, in fact it was still dependent on the polymorphic crystal structure of PBA. The morphological changes of PBA films after enzymatic degradation confirmed again that the epitaxial crystallization only occurred for the PBA film with α crystal structure which was produced by being sandwiched between oriented Teflon films, and it happened only on the surface of PBA films.     

末端为磷酰胆碱基团的聚丁二酸丁二醇酯的酶促降解和热性能

以聚丁二酸丁二醇酯(PBS)为参照, 研究了酯酶Lipase AY30对亲水磷酰胆碱(PC)基团改性的聚丁二酸丁二醇酯(PBS-PC)的生物降解性能的影响. 结果显示, 在酯酶Lipase AY30作用下, 21 d后PBS的质量损失仅为1.9%, 而PBS-PC的质量损失了9.7%. 相同条件下扣除各自水解引起的质量损失(PBS 1.4%和PBS-PC 6.5%)后, PC亲水基团的引入对聚合物的降解起到了促进作用. 示差扫描量热(DSC)研究结果表明, 改性后的聚合物熔融温度和熔融焓降低, 玻璃化转变温度升高, 表明PC端基的引入降低了PBS的结晶能力, 非晶相结构的增多对聚合物降解有促进作用. 因此PBS-PC有望作为一种新的具有良好生物降解性和生物相容性的高分子材料, 应用于药物控释、基因治疗及组织工程等生物医用材料领域.     

Effects of crystallization temperature and blend ratio on the crystal structure of poly(butylene adipate) in the poly(butylene adipate)/poly(butylene succinate) blends

The effects of crystallization temperature and blend ratio on the polymorphic crystal structures of poly(butylene adipate)(PBA) in poly(butylene succinate)(PBS)/poly(butylene adipate)(PBS/PBA) blends were studied by means of differential scanning calorimetry(DSC), wide-angle X-ray diffraction(XRD) and atomic force microscopy(AFM). It was revealed that the polymorphism of PBA can be regulated by the blend ratio even in a non-isothermal crystallization process. The results demonstrate that high temperature favors flat-on α crystals, while low temperature contributes to edge-on β crystals. It was also found that the effect of blend ratio on the crystallization mechanism of PBA is well coincident with that of the crystallization temperature. The increment of PBS content in the PBS/PBA blend gives rise to more β-form crystals of PBA. For those PBS/PBA blends with low PBA content, the interlamellar phase segregation of PBA makes its molecular chains so difficult to diffuse from one isolated microdomain to another that high crystallization temperature and sufficiently long crystallization time will be required if the PBA α-type crystals are targeted.     

Thermal and mechanical properties of mandelic acid‐copolymerized poly(butylene succinate) and poly(ethylene adipate)

Phenyl side chains were introduced to poly(butylene succinate) and poly(ethylene adipate) by the polymerization of the respective monomers in the presence of mandelic acid. The increasing content of the phenyl side chains decreased the melting temperature and the crystallinity but increased the glass‐transition temperature of the aliphatic polyesters. The phenyl side branches reduced the crystallinity of poly(butylene succinate) more significantly than the ethyl or n‐octyl side branches did. The tensile strength, elongation, and tear strength of poly(ethylene adipate) decreased with an increase in the content of mandelic acid units. However, the increasing content of mandelic acid units enhanced the elongation and tear strength of poly(butylene succinate) considerably without a notable deterioration of tensile strength. The biodegradability of the copolyesters was increased as a result of the introduction of more mandelic acid units due to the decrease in the crystallinity. © 2000 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 38: 1504–1511, 2000     

Miscibility and Crystallization in Binary Crystalline Blends of Poly(butylene terephthalate) with Poly(butylene terephthalate-e-caprolactone)

Poly(butylene terephthalate)/poly(butylene terephthalate-e-caprolactone) is a new A/AxB1-x binary crystalline blend with intra-molecular repulsion interaction. Using the mean-field binary interaction model, the value of interaction parameter between the butylene terephthalate and caprolactone structural unit was first reported to be 0.305. This blend exhibited different crystallization behavior from a typical homopolymer/copolymer blend, which was carefully investigated by di?erential scanning calorimetry. It was found that poly(butylene terephthalate-e-caprolactone) copolymers have a great effect on the pure poly(butylene terephthalate) chain mobility and poly(butylene terephthalate) crystalline lattice packing. In the meantime, the crystallization of butylene terephthalate segments in copolymers was restricted by the previously formed poly(butylene terephthalate) crystallites. The two constituents for blending can not form a co-crystal in the range of composition even if they have the same butylene terephthalate unit. It can be concluded that longersegments in a copolymer would be beneficial for the formation of a co-crystal in blends.     

Atomic Force Microscopy Characterization and Interpretation of Thin‐Film Poly(butylene adipate) Spherulites with Ring Bands

Atomic force microscopy characterization has been conducted to reveal the morphological difference between single‐ring bands in poly(butylene adipate) (PBA). Furthermore, morphological features of the ring‐less Maltese‐cross spherulites are compared to the ring‐band spherulites. Periodic changes in height seem to be common for either the ring‐band or ring‐less (Maltese‐cross) crystal domains; however, the steepness in height change is greater for the ring‐band crystal, while height change in the ring‐less crystal exhibits a terrace‐like layer pattern. In the ring‐band crystal region, the lamellar stalks, which taper off to pointed needle‐like stalks, monotonously protrude out of the layers of softer materials, with no signs of twisting, bending, or turning. In contrast, all lamellae in the ring‐less (Maltese‐cross) crystal region are uniform platelets arranged like flower petals in a layered pattern.

     

Thermal properties of poly(butylene oxalate) copolymerized with azelaic acid

Poly(butylene oxalate) (PBO) and poly(butylene oxalate/butylene azelate) random copolymers (PBOBAz) of various compositions were synthesized in bulk and characterized in terms of chemical structure and thermal properties. The thermal behavior was examined by thermogravimetric analysis and differential scanning calorimetry. All copolymers were found to be partially crystalline and thermally stable up to about 290 °C. The main effect of copolymerization was a decrease in melting and glass transition temperatures with respect to PBO homopolymer. The pure crystalline phase characteristic of PBO was evidenced by means of X-ray measurements in all the copolymers under investigation. The fusion temperatures appeared to be well correlated to composition by Baur's equation.Amorphous samples were obtained after melt quenching and showed a monotonic decrease of glass transition temperatures as the content of the flexible butylene azelate units is increased. Fox equation described well the T_g-composition data. Lastly, the overall crystallization rate of PBO was found to decrease regularly with increasing butylene azelate unit content.     

Biodegradable Foaming Material of Poly(butylene adipate-co-terephthalate) (PBAT)/Poly(propylene carbonate) (PPC)

A biodegradable blend foaming material of poly(butylene adipate-co-terephthalate)(PBAT)/poly(propylene carbonate)(PPC)was successfully prepared by chemical foaming agent and screw extrusion method.First,PBAT was modified by bis(tert-butyl dioxy isopropyl)benzene(BIBP)for chain extension,and then the extended PBAT(E-PBAT)was foamed with PPC using a twin(single)screw extruder.By analyzing the properties of the blends,we found that Young’s modulus increased from 58.8 MPa of E-PBAT to 244.7 MPa of E-PBAT/PPC 50/50.The viscosity of the polymer has a critical influence on the formation of cells.Compared with neat PBAT(N-PBAT),the viscosity of E-PBAT increased by 3396 Pa·s and E-PBAT/PPC 50/50 increased by 8836 Pa·s.Meanwhile,the dynamic mechanical analysis(DMA)results showed that the storage modulus(E’)at room temperature increased from 538 MPa to 1650 MPa.The various phase morphologies(“sea-island”,“quasi-co-continuous”and“cocontinuous”)and crystallinity of the blends affected the spread velocity of gas and further affected the foaming morphology in E-PBAT/PPC foam.Therefore,through the analysis of phase morphology and foaming mechanism,we concluded that the E-PBAT/PPC 70/30 component has both excellent strength and the best foaming performance.     

生物可降解共聚物聚丁二酸/对苯二甲酸丁二醇酯(PBST)的序列结构及结晶性研究

制备了高分子量的聚丁二酸丁二醇酯,并通过与对苯二甲酸二甲酯的无规共聚调节其生物可降解性及力学性能,得到了具有优良机械性能和不同生物降解速度的一系列共聚物,并对共聚物序列结构、热力学性能、结晶性进行了研究.结果表明,该共聚物为无规共聚物,PBS和PBT分别结晶.共聚物的结晶熔点符合无规共聚物的Flory方程.