离子液体增塑改性玉米淀粉/聚丁二酸丁二醇酯共混材料的结构与性能

为考察离子液体对淀粉/聚丁二酸丁二醇酯(PBS)的作用效果,降低淀粉/PBS的脆性,以离子液体(1-丁基-3-甲基咪唑氯盐[BMIM]Cl)作为增塑改性剂通过熔融共混法制备了玉米淀粉/聚丁二酸丁二醇酯(PBS)共混材料,采用红外光谱(FTIR)、扫描电镜(SEM)、热重分析(TGA)、X射线衍射分析(XRD)及力学性能测试方法研究了[BMIM]Cl对淀粉/PBS共混材料结构和性能的影响.结果表明,[BMIM]Cl能与淀粉/PBS分子发生强相互作用,破坏淀粉/PBS共混物中原有的氢键与结晶结构,增强界面相互作用,改善相容性,进而改变淀粉/PBS共混材料的结构与性能;[BMIM]Cl的加入不影响淀粉/PBS的热稳定性,可使材料玻璃化转变温度(Tg)、结晶温度(Tc)、冷结晶温度(Tcc)及结晶度(Xc)降低.[BMIM]Cl具有显著降低淀粉/PBS脆性的作用,使其断裂伸长率大幅度增加,拉伸强度和弹性模量降低.     

聚2,5-呋喃二甲酸乙二醇酯/聚丁二酸丁二醇酯共混物的制备与表征

通过熔融共混制备了聚2,5-呋喃二甲酸乙二醇酯(PEF)/聚丁二酸丁二醇酯(PBS)共混物,探究了制备PEF/PBS共混物的影响因素,考察了共混温度、共混时间、螺杆转速、共混比例对PEF/PBS共混物力学性能的影响因素,并用示差扫描量热仪、热失重、扫描电子显微镜等技术手段对其热性能和相容性进行了表征。 结果表明,当PBS的含量为15%、共混温度为230 ℃,共混时间为90 s、螺杆转速为150 r/min时,为最佳共混制备条件,此时相容性最好,热性能良好,冲击强度和拉伸强度最大,冲击强度相对纯PEF提高了6倍,拉伸强度提高了近20%,从而大幅提高了PEF的冲击强度,有效地增强了PEF的抗冲击韧性。 这些工作为这一生物基聚酯材料的应用提供了可能。     

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。     

聚丁二酸丁二醇酯的研究进展

聚丁二酸丁二醇酯(PBS)是一种具有生物相容性和生物降解性的脂肪族聚酯,其在药物控制释放、手术缝合线等生物医药领域有广阔的应用前景.本文综述了PBS的合成、改性方法及其作为药物缓释载体的应用.提出今后PBS研究的重点将集中在功能化基团的引入、合成路线的简化、成本的降低及其改性后材料的相关性能等方面.     

末端带有磷酰胆碱基团的聚丁二酸丁二醇酯的合成、表征和性能研究

采用四步反应合成了一种新的具有良好生物相容性和生物降解性的末端带有磷酰胆碱(PC)基团的聚丁二酸丁二醇酯PBS-PC. 采用1H NMR、IR、凝胶色谱(GPC)和X射线光电子能谱(XPS)表征了聚合物的结构. 同时研究了聚合物的亲疏水性能、体外降解、溶胀率和对模型药物中性红的缓释性能. 结果显示: PC基团引入, 在一定程度上提高了PBS的亲水性、降解速率、溶胀率和对中性红的缓释性能.     

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.     

生物降解高分子材料聚丁二酸丁二醇酯的改性研究进展

生物降解高分子材料被公认为是聚丙烯、聚乙烯等传统高分子材料造成"白色污染"的问题的重要解决方法之一。聚丁二酸丁二醇酯是重要的可生物降解的脂肪族聚酯之一,因与传统的聚丙烯、聚乙烯高分子材料具有相近的物理和力学性能,从而引起科学与工业界的广泛重视。然而,与大多数脂肪族聚酯一样,PBS材料也存在着加工、种类少、性能应用上的缺点。因此,对其通过改性拓宽用途范围的研究报道也随之增多。本文从化学、物理等改性的手段方法为着眼点,分类阐述了近些年来生物降解高分子材料聚丁二酸丁二醇酯改性研究现状与进展。     

聚丁二酸丁二醇酯的自成核结晶行为

利用差示扫描量热仪(DSC)研究了自成核对聚丁二酸丁二醇酯(PBS)的结晶行为的影响. 研究结果表明, PBS的有效自成核温度处理区间为118～120 ℃. PBS经自成核处理后结晶温度提高, 可以在100~118 ℃温度区间内迅速结晶. 同时, 研究了自成核处理后样品在100～104 ℃范围内的等温结晶行为、动力学过程及熔融行为. 结果表明, 随着等温结晶温度的升高, 结晶速率变慢, 熔融曲线出现多重熔融峰. Hoffman-Weeks方程分析结果表明, 自成核处理对PBS的平衡熔点没有影响. Avrami等温结晶动力学方程适合分析自成核处理样品的等温结晶动力学过程, 获得其动力学参数K与n, 其中n值偏大的原因在于自成核的样品结晶生长点增多. 根据Arrhenius方程, 计算获得PBS自成核处理后等温结晶活化能为-286 kJ/mol.     

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.     

热塑性淀粉/PBS共混物的微生物降解性研究

以甘油作为增塑剂,采用玉米淀粉与改性后的聚丁二酸丁二醇酯(PBS)熔融共混制备出淀粉/PBS共混材料.对这种改善了两相相容性的共混材料在特定微生物条件下的降解行为进行了研究.结果显示,共混物降解28天后,含有30%PBS的共混物质量损失达到35%左右,其力学性能只有降解前的20%,甘油含量减小和PBS含量增加均能减缓材料的降解.且随着降解时间的延长,PBS的结晶度和熔点有所提高.     

Blends of Poly（lactic acid） with Thermoplastic Acetylated Starch

Blends of poly(lactic acid)(PLA) and thermoplastic acetylated starch(ATPS) were prepared by means of the melt mixing method. The results show that PLA and ATPS were partially miscible, which was confirmed with the measurement of Tg by dynamic mechanical analysis(DMA) and differrential scanning calorimetry(DSC). The mechanical and thermal properties of the blends were improved. With increasing the ATPS content, the elongation at break and impact strength were increased. The elongation at break increased from...     

水辅助加工法制备聚丙撑碳酸酯/淀粉共混物

分别采用普通熔融共混法和水辅助加工法,制备了具有不同共混形态的聚丙撑碳酸酯(PPC)/淀粉共混物,并研究了淀粉分散形态对共混物的玻璃化转变温度(Tg)、流变以及力学性能的影响。研究结果表明,采用普通熔融共混法时,淀粉未发生糊化,并以原颗粒状分散于基体中;而采用水辅助加工法时,淀粉发生糊化,并在挤出过程中原位形成纤维结构。当淀粉以纤维形式分散于PPC基体中时,其与PPC间的界面接触面积显著增加,二者的相互作用增强,PPC/淀粉共混物的Tg、储能模量以及复合黏度显著提高。力学性能测试结果表明,当淀粉质量分数为30%,采用水辅助加工法制备的PPC/淀粉共混物的拉伸模量相比于纯PPC提高了67.7%。     

Elaboration and Characterization of Starch/ Poly(caprolactone) Blends

A starch-based biodegradable material was prepared in two steps. Firstly, starch was chemically modified by using formic acid at 20°C to obtained degrees of substitution of about 1.2. The level of destructuration was also assessed using dynamic rheological measurements. Native starch or starch ester were then mixed with poly(caprolactone) and different polyester oligomers were added as compatibilisers and plasticizing agents. PCL oligomers were found to be the most efficient ones. A significant improvement of the elongation at break of starch formate/PCL/oligo PCL blends was achieved.     

High-Toughness Poly(lactic Acid)/Starch Blends Prepared through Reactive Blending Plasticization and Compatibilization

In this study, poly(lactic acid) (PLA)/starch blends were prepared through reactive melt blending by using PLA and starch as raw materials and vegetable oil polyols, polyethylene glycol (PEG), and citric acid (CA) as additives. The effects of CA and PEG on the toughness of PLA/starch blends were analyzed using a mechanical performance test, scanning electron microscope analysis, differential scanning calorimetry, Fourier-transform infrared spectroscopy, X-ray diffraction, rheological analysis, and hydrophilicity test. Results showed that the elongation at break and impact strength of the PLA/premixed starch (PSt)/PEG/CA blend were 140.51% and 3.56 kJ·m⁻², which were 13.4 and 1.8 times higher than those of pure PLA, respectively. The essence of the improvement in the toughness of the PLA/PSt/PEG/CA blend was the esterification reaction among CA, PEG, and starch. During the melt-blending process, the CA with abundant carboxyl groups reacted in the amorphous region of the starch. The shape and crystal form of the starch did not change, but the surface activity of the starch improved and consequently increased the adhesion between starch and PLA. As a plasticizer for PLA and starch, PEG effectively enhanced the mobility of the molecular chains. After PEG was dispersed, it participated in the esterification reaction of CA and starch at the interface and formed a branched/crosslinked copolymer that was embedded in the interface of PLA and starch. This copolymer further improved the compatibility of the PLA/starch blends. PEGs with small molecules and CA were used as compatibilizers to reduce the effect on PLA biodegradability. The esterification reaction on the starch surface improved the compatibilization and toughness of the PLA/starch blend materials and broadens their application prospects in the fields of medicine and high-fill packaging.     

新型热塑性淀粉的制备和性能

以二甲基亚砜(DMSO)为增塑剂, 通过熔融共混法制备了一种新型热塑性淀粉(TPS), 研究不同增塑剂含量对材料结构和性能的影响, 并与甘油及甘油/水复合增塑淀粉体系进行了比较. FTIR结果显示, DMSO能够与淀粉产生强烈而稳定的氢键相互作用. WAXD和SEM的研究结果表明, DMSO的加入破坏了淀粉的有序结构, 实现了淀粉的塑化, 形成均一的非晶连续相. 同甘油及甘油/水增塑体系相比, DMSO与淀粉的羟基形成更为稳定的氢键, 能够有效抑制淀粉的重结晶. 动态力学和拉伸力学性能测试结果表明, 经过DMSO的增塑, 有效降低了淀粉的玻璃化转变温度, 改善了材料的韧性, 增塑效率要好于甘油及甘油/水复合增塑体系.     

聚甲基丙烯酸甲酯与聚醋酸乙烯酯共混的红外光谱研究

用红外光谱(FTIR)研究了聚甲基丙烯酸甲酯(PMMA)与聚醋酸乙烯酯(PVAc)共混体系相容性,在160℃以上共混体系发生相分离;分相体系与非分相体系的FTIR谱明显不同;共混体系的FTIR谱不能从两统组分红外光谱简单加和得到;结果表明大分子构象发生了变化,PMMA/PVAc体系相容可能是大分子构象熵变所致。     

羧化聚苯醚／聚（苯乙烯—乙烯吡啶）共混相容性

用ＤＳＣ、ＤＭＡ研究了羧化聚苯醚（ＣＰＰＯ）／聚（苯乙烯－乙烯吡啶）（ＰＳＶＰ）共混体系的相容性，结果表明，与ＣＰＰＯ／ＰＳ体系相比，乙烯吡啶基的引入大大提高了共混相容性．这主要是由于ＣＰＰＯ中的羧基与ＰＳＶＰ中的吡啶基之间通过质子转移形成的正负离子间的相互作用，推动了两组分分子的均匀混合．     

Studies on Poly(Methyl Methacrylate) (PMMA) and Thermoplastic Polyurethane (TPU) Blends

Blends of poly(methyl methacrylate) (PMMA) and thermoplastic polyurethane (TPU) in different compositions viz., 95/5, 90/10, 85/15 and 80/20 (by wt/wt, % of PMMA/TPU) were blended by melt mixing using a twin‐screw extruder. All the PMMA/TPU blends have been characterized for physico‐mechanical properties such as density, melt flow index, tensile behavior and izod impact strength. The impact strength of the PMMA/TPU blends were found to increase significantly with an increase in the percentage of TPU up to 20%, by retaining the tensile strength of PMMA. The effect of chemical aging on the performance of blends has been studied.     

聚β—羟基丁酸酯／聚醋酸乙烯酯共混体系的相容性与结晶行为

研究了制样过程聚β－羟基丁酸酯／聚醋酸乙烯酯共混体系的相容性和结晶行为的影响。ＤＳＣ、ＳＡＸＳ、ＰＯＭ等实验结果表明，ＰＨＢ／ＰＶＡｃ共混物经溶液成膜后处于分相的状态，ＰＶＡｃ对ＰＨＢ的结晶能力影响不大；而经融处理后，ＰＨＢ／ＰＶＡｃ共混物则处于相容的均相状态，随ＰＶＡｃ的含量含量的增加。