PVC片材表面的光接枝亲水化处理

采用光接枝聚合方法对商品化PVC片材进行了表面亲水化处理。以二苯甲酮作引发剂 ,丙烯酸为接枝单体研究了反应过程中单体浓度、引发剂浓度、反应时间对亲水化效果的影响。衰减全反射红外光谱 (ATR FTIR)分析发现 ,在 15 5 5cm-1处出现COO-的特征峰 ,证明丙烯酸已经接枝到材料表面。随着反应时间的延长 ,接触角持续下降 ,3 0s以后趋于恒定 ,最低可达 3 3°。较低单体浓度下 ,均聚反应较弱 ,材料的亲水性要好于高单体浓度时的情况。同样 ,较低引发剂浓度时 ,引发剂的自屏蔽效应弱 ,有利于接枝反应 ,接触角要比高引发剂浓度条件下小     

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%。     

聚丙烯纤维在聚3-羟基丁酸酯与木质素对甲酚复合膜中的改性作用研究

研究了聚3-羟基丁酸酯/聚丙烯纤维(PHB/PP)复合膜和PHB/PP/木质素对甲酚复合膜的力学和热力学性能的影响,分别探讨了PP纤维和木质素对甲酚的添加量对复合膜性能的影响。结果表明,PP纤维含量为8 %且木质素对甲酚含量为3 %时,PHB/PP/木质素对甲酚复合膜的综合性能最佳,适量的PP纤维改善了PHB的拉伸强度,并且木质素对甲酚一定程度上改善了复合膜的热降解性能。     

聚3–羟基丁酸与4–羟基丁酸共聚物薄膜的微生物降解

以门多萨假单胞菌为降解菌株,研究了聚3–羟基丁酸与4–羟基丁酸共聚物[poly(3HB-co-4HB)]薄膜的微生物降降过程。门多萨假单胞菌对poly(3HB-co-4HB)薄膜的降解可分为慢速降解阶段和快速降解阶段。经10 d的降解,薄膜的降解率可达到94.7%。扫描电子显微镜观察发现,经微生物降解的薄膜表面因降解而形成的孔洞及蚀痕,这些孔洞及蚀痕随着降解时间的增加有着加大和加深的情况。差示扫描量热法分析发现,随微生物降解时间的增加,薄膜的熔点上升,而相对结晶度降低。X射线衍射分析结果也进一步证实了薄膜经微生物降解后相对结晶度的降低。热重分析法也证明薄膜的热稳定性随降解时间增加而下降。     

聚(3-羟基丁酸和4-羟基丁酸酯)共聚物与聚乳酸共混体系性能研究

研究了可完全生物降解的聚(3-羟基丁酸-co-4-羟基丁酸醋)与聚乳酸(PLA)共混体系,利用偏光显微镜、动态和静态剪切流变、X射线衍射和差示扫描量热仪,分析共混体系的结晶性能、流变性能和热稳定性。结果表明:随着PLA添加量增加,熔融温度由156.05℃降低到130. 32 C,结晶温度由102. 09℃降低62. 33 C,结晶度下降。而玻璃化转变温度由一5 . 69℃上升3. 42 C,体系的热稳定性和豁弹性提高。     

聚(3-羟基丁酸酯)的化学改性研究进展

评述了降解塑料聚(3 羟基丁酸酯)(PHB)近年来在化学改性方面的研究进展情况,特别就PHB化学改性的方法和产物的性能进行了总结和评述。PHB化学改性的方法包括辐射聚合、大单体反应改性、反应性共混等。PHB化学改性可通过分子设计合成特定结构的PHB共聚物,具有物理共混无法比拟的优势,特别是在组织工程领域有着广泛的应用前景。     

聚(3-羟基丁酸酯)的共混改性

聚（3－羟基丁酸酯）（PHB）的共混改性是目前研究的一个重要，本文主要从热行为，结晶行为等方面论述了研究较多的PHB与热塑性高聚物，橡胶及多糖类的共混行为及其结果。     

Biodegradable polymer blends of poly(3-hydroxybutyrate) and poly(DL-lactide)-co-poly(ethylene glycol)

The melting and crystallization behavior and phase morphology of poly(3-hydroxybutyrate) (PHB) and poly(DL-lactide)-co-poly(ethylene glycol) (PELA) blends were studied by DSC, SEM, and polarizing optical microscopy. The melting temperatures of PHB in the blends showed a slight shift, and the melting enthalpy of the blends decreased linearly with the increase of PELA content. The glass transition temperatures of PHB/PELA (60/40), (40/60), and (20/80) blends were found at about 30°C, close to that of the pure PELA component, during DSC heating runs for the original samples and samples after cooling from the melt at a rate of 20°C/min. After a DSC cooling run at a rate of 100°C/min, the blends showed glass transitions in the range of 10–30°C. Uniform distribution of two phases in the blends was observed by SEM. The crystallization of PHB in the blends from both the melt and the glassy state was affected by the PELA component. When crystallized from the melt during the DSC nonisothermal crystallization run at a rate of 20°C/min, the temperatures of crystallization decreased with the increase of PELA content. Compared with pure PHB, the cold crystallization peaks of PHB in the blends shifted to higher temperatures. Well-defined spherulites of PHB were found in both pure PHB and the blends with PHB content of 80 or 60%. The growth of spherulites of PHB in the blends was affected significantly by 60% PELA content. © 1997 John Wiley & Sons, Inc. J Appl Polym Sci 65: 1849–1856, 1997     

Lamellar Morphology of Poly(3-hydroxybutyrate)/Poly(ethylene oxide) Blends as Studied via Small Angle X-ray Scattering

The lamellar morphology of a melt-miscible blend consisting of two crystalline constituents, poly(3-hydroxybutyrate) (PHB) and poly(ethylene oxide) (PEO) have been investigated by means of small angle X-ray scattering (SAXS). The blend was a crystalline/amorphous system when temperatures lay between the melting point of PEO (ca. T _m ^PEO=60C) and that of PHB (ca. T _m ^PHB=170C), while it became a crystalline/crystalline system below T _m ^PEO. The crystalline microstructures of the blends were induced by two types of crystallization history, i.e. one-step and two-step crystallizations. In the one-step crystallization, the blends were directly quenched from the melt to room temperature to allow simultaneous PHB and PEO crystallization. The two-step crystallization involved first cooling to 70C to allow PHB crystallization for 72 h followed by cooling to room temperature (ca. 19C) to allow PEO crystallization. In the crystalline/crystalline state, two scattering peaks have been observed in the Lorentz-corrected SAXS profiles, irrespective of the crystallization histories, meaning that crystallization created separate PHB and PEO lamellar stack domains. One-step crystallization yielded lamellar stack domains containing almost pure PHB and PEO lamellae. Two-step crystallization generated almost pure PHB lamellar domains and the PEO lamellar domains with inserted PHB lamellae. In the crystalline/amorphous state, the composition dependence of the amorphous layer thickness (l _a), the presence of zero-angle scattering, and the volume fraction of the PHB lamellar stack (_s) revealed that both one-step and two-step crystallizations, generated the interfibrillar segregation morphology, where the extent of interfibrillar segregation of amorphous PEO increased with increasing PEO content.     

Thermal analyses of poly(3-hydroxybutyrate), poly(3-hydroxybutyrate-co-3-hydroxyvalerate), and poly(3-hydroxybutyrate-co-3-hydroxyhexanoate)

Thermal analyses of poly(3-hydroxybutyrate) (PHB), poly(3-hydroxybutyrate-co-3-hydroxyvalerate) [P(HB–HV)], and poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) [P(HB–HHx)] were made with thermogravimetry and differential scanning calorimetry (DSC). In the thermal degradation of PHB, the onset of weight loss occurred at the temperature (°C) given by T_o = 0.75B + 311, where B represents the heating rate (°C/min). The temperature at which the weight-loss rate was at a maximum was T_p = 0.91B + 320, and the temperature at which degradation was completed was T_f = 1.00B + 325. In the thermal degradation of P(HB–HV) (70:30), T_o = 0.96B + 308, T_p = 0.99B + 320, and T_f = 1.09B + 325. In the thermal degradation of P(HB–HHx) (85:15), T_o = 1.11B + 305, T_p = 1.10B + 319, and T_f = 1.16B + 325. The derivative thermogravimetry curves of PHB, P(HB–HV), and P(HB–HHx) confirmed only one weight-loss step change. The incorporation of 30 mol % 3-hydroxyvalerate (HV) and 15 mol % 3-hydroxyhexanoate (HHx) components into the polyester increased the various thermal temperatures T_o, T_p, and T_f relative to those of PHB by 3–12°C (measured at B = 40°C/min). DSC measurements showed that the incorporation of HV and HHx decreased the melting temperature relative to that of PHB by 70°C. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 90–98, 2001     

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.     

聚丁二酸丁二醇酯的表面改性及相关研究

分别使用O_2 PⅢ和N_2 PⅢ对聚丁二酸丁二醇酯(PBS)进行表面改性.X射线光电子能谱(XPS)和接触角测试结果表明:O_2PⅢ和N_2PⅢ分别在试样表面引入了大量的含氧基团和含氮基团,且引入的含氧基团和含氮基团都极大地提高了试样表面的亲水性.hFOB 1.19细胞培养结果表明:O_2 PⅢ和N_2PⅢ都能够明显地改善PBS试样的骨细胞相容性,且O_2PⅢ效果更佳.     

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.     

邻苯二甲酸二辛酯与PHB共混改性的研究

采用邻苯二甲酸二辛酯(DOP)对聚3-羟基丁酸酯(PHB)进行共混改性,并对共混物的流变行为、结晶行为和力学行为进行了研究。结果表明,DOP与PHB具有良好的相容性,能降低PHB的结晶行为,降低熔融温度,加宽熔融温区,改善加工条件,提高韧性。     

聚羟基丁酸己酸酯对聚羟基丁酸戊酸酯结晶性能的影响

采用溶液浇铸法制备了生物可降解聚羟基丁酸戊酸酯（PHBV）和聚羟基丁酸己酸酯（PHBHHx）共混物,用差示扫描量热仪和偏光显微镜研究了PHBHHx对PHBV热性能与结晶性能的影响。结果表明,PHBV和PHBHHx之间存在一定的相互作用,PHBV的冷结晶温度随PHBHHx含量的增加向高温方向移动;PHBV/PHBHHx共混物的结晶呈环带球晶现象,随PHBHHx含量的提高,环带球晶逐渐变得规整、清晰,且带宽逐渐减小。     

Biodegradable polymer blends of poly(3-hydroxybutyrate) and starch acetate

The thermal behaviour and phase morphology of poly(3-hydroxybutyrate) (PHB) and starch acetate (SA) blends have been studied by differential scanning calorimetry, Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy and polarizing optical microscopy. PHB/SA blends were immiscible. The melting temperatures of PHB in the blends showed some shift with increase of SA content. The melting enthalpy of the PHB phase in the blend was close to the value for pure PHB. The glass transition temperatures of PHB in the blends remained constant at 9°C. The FTIR absorptions of hydroxyl groups of SA and carbonyl groups of PHB in the blends were found to be independent of the second component at 3470cm^-1 and 1724cm^-1, respectively. The crystallization of PHB was affected by the addition of the SA component both from the melt on cooling and from the glassy state on heating. The temperature and enthalpy of non-isothermal crystallization of PHB in the blends were much lower than those of pure PHB. The crystalline morphology of PHB crystallized from the melt under isothermal conditions varied with SA content. The cold crystallization peaks of PHB in the blends shifted to higher temperatures compared with that of pure PHB. ©1997 SCI     

Synthesis and Surface Properties of Poly(methyl methacrylate)/Poly(ethylene glycol) Binary Brushes

A new kind of binary polymer brushes was synthesized from two immiscible polymers, PMMA and PEG, on GPS‐modified silicon wafers. Surface composition, layer thickness, coverage, chain density, wetting ability, morphology and protein adsorption of the binary brushes were investigated by XPS, ellipsometry, AFM and contact angle measurements. The results show that both PMMA and PEG were successfully grafted onto the surface. The surface coverage and the chain density of PMMA and PEG brushes can be controlled by modulating the reaction temperature and time. This kind of binary polymer brushes exhibits a distinct microphase‐separated structure and excellent protein‐preventing property.

     

聚3-羟基丁酸酯降解技术研究进展

综述了目前聚3-羟基丁酸酯（poly-3-hydroxybutyrate,PHB）的几种主要降解技术,包括热裂解、水解、溶剂降解和酶解等。重点介绍了各种降解技术的产物分布和反应机理,并对影响PHB热稳定性的主要因素进行了总结和讨论。各种技术的所需反应温度总体趋势为：热裂解>水解≥溶剂降解>酶解。PHB热解工艺简单,通常情况下PHB主要降解为巴豆酸和其低聚物,过高反应温度（>500℃）则使PHB分解为二氧化碳和丙烯。水解和溶剂降解都是以针对性地断开PHB酯键为出发点,以获得高产率的PHB单体（3-羟基丁酸、巴豆酸）或其酯类化合物（如巴豆酸甲酯）。与热解、水解和溶剂降解技术相比,酶解法限制因素较多且工艺成本高,需要新的技术突破。提出了两个需进一步重点研究的方向：①PHB催化热解脱羧制备高品位液体燃料;②直接转化富含PHB的微生物为高价值化学品。     

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。     

聚甲基丙烯酸甲酯包覆纳米CaCO3改性聚氯乙烯研究

研究了聚甲基丙烯酸甲酯(PMMA)包覆纳米CaCO3复合粒子填充聚氯乙烯(PVC)复合材料的加工塑化和力学性能，并与未改性纳米CaCO3的改性效果进行比较。结果发现，填充纳米CaCO3使PVC平衡扭矩和平衡熔融温度均会有所提高，填充未改性碳酸钙增加更大，填充PMMA包覆CaCO3使材料冲击性能提高的幅度大于填充未改性纳米CaCO3，而拉伸强度下降幅度较小。当PMMA包覆CaCO3填充量为8％时缺口冲击强度增加到未改性PVC的194％。冲击缺口断面形态分析表明，采用PMMA包覆CaCO3时，纳米CaCO3在PVC基体中分散均匀、团聚少。