UHMWPVC／LMWPVC共混增塑体系流变行为的研究

采用机械方法将ＴＨ－４００型ＬＭＷＰＶＣ与Ｐ－２５００型ＵＨＭＷＰＶＣ共混增塑，并对共混增塑体系的流变性能进行了系统的研究。结果表明，该体系为典型的假塑性流体，其非牛顿指数ｎ随着剪切速率的增大而减小，随着温度的升高而增大。ＬＭＷＰＶＣ的加入，有效地降低了共混体系的粘度。当剪切速率大于２４３ｓ＾－１后，体系的粘流活化能明显降低，试样的ＳＥＭ照片表明，随着剪切速率的增大，熔体中的初级粒子尺寸减小。该体     

共混方式对PP／UHMWPE合金的力学性能和形态结构的影响

采用四螺杆挤出机和双螺杆挤出机将ＰＰ和ＵＨＭＷＰＥ挤出共混制成ＰＰ／ＵＨＭＷＰＥ合金，并测试其力学性能。用ＳＥＭ和ＤＳＣ对两种共混方式所制备的合金的亚微形态和热性能进行了考察。发现四螺杆挤出机能将ＵＨＭＷＰＥ均匀地分散在ＰＰ基体中，使合金的缺口冲击强度和其它力学性能得到显著的提高，其冲击样条断裂面上呈现细点状结构；同时在合金中，ＵＨＭＷＰＥ与ＰＰ形成共晶结构，并导致ＵＨＭＷＰＥ熔点下降；表明ＵＨＭ     

钛基-TiN-TiC系梯度薄膜材料的生物摩擦磨损特性研究

在ＳＲＶ试验机上用血清润滑对钛合金及钛基－Ｔｉｎ－ＴｉＣ梯度薄膜与ＵＨＡＭＷＰＥ摩擦副摩擦磨损性能进行了测试与比较,并对其磨损机理进行了分析。研究结果表明,钛基－ＴｉＮ－ＴｉＣ梯度薄膜材料表面硬度得到提高,达到２６３０ＨＶ,与基力,生物耐磨性明显提高,为发展耐磨性好的人工关节材料探索了一条新的途径。     

分子量对PP／UHMWPE合金的力学性能,形态和流变行为的影响

用分子量分别为１．２×１０￣６、２．５×１０￣６和３．５×１０￣６的ＵＨＭＷＰＥ与ＰＰ共混制成合金，并对这些合金的力学性能、亚微形态和流变行为进行了研究。发现ＰＰ／ＵＨＭＷＰＥ合金的力学性能对ＵＨＭＷＰＥ的分子量有较大的依赖性，ＵＨＭＷＰＥ的分子量越高，则合金的Ｉｚｏｄ冲击强度、拉伸强度、弯曲强度和弯曲模量也越高。用ＳＥＭ对冲击样条的断裂形貌研究表明，当ＵＨＭＷＰＥ的分子量高于２．５×１０￣６后，合金的断裂行为完全不同于分子量为１．２×１０￣６的ＵＨＭＷＰＥ与ＰＰ合金，前者呈典型的延性断裂。此外，ＵＨＭＷＰＥ的分子量对ＰＰ／ＵＨＭＷＰＥ合金的流变性能也有一定的影响，而这种影响正是由于不同分子量的ＵＨＭＷＰＥ在合金中形态结构的差异所致。     

共混方式对PP／UHMWPE合金的力学性能的形态结构的影响

采用四螺杆挤出机和双螺杆挤出机将ＰＰ和ＵＨＭＷＰＥ挤出共混制成ＰＰ／ＵＨＭＷＰＥ合金,并测试其力学性能,用ＳＥＭ和ＤＳＣ对两种共混方式所制备的合金的亚微形态和热性能进行了考察。发现四螺杆挤出机能将ＵＨＭＷＰＥ均匀地分散在ＰＰ基体中,使合金的缺口冲击强度和其它力学性能得到显著的提高,其冲击样条断裂面上呈现细点状结构;同时在合金中,ＵＨＭＷＰＥ与ＰＰ形成共晶结构,并导致ＵＨＭＷＰＥ熔点下降;表明ＵＨＭＷＰＥ以准分子水平分散在ＰＰ基体中,形成“线性互穿网络”结构。而双螺杆挤出机对ＰＰ／ＵＨＭＷＰＥ合金的共混效果却不佳,所制备的合金的力学性能不能得到有效的提高,冲击样条断口呈现典型的脆性断裂行为;合金中也不存在共晶结构。证明对于ＰＰ／ＵＨＭＷＰＥ合金,四螺杆挤出机比双螺杆挤出机具有更好的共混效果。     

聚氯乙烯结晶行为研究

采用差示扫描量热（ＤＳＣ）法研究了聚氯乙烯（ＰＶＣ）原粉树脂和重结晶试吉晶性能，结果表明，ＰＶＣ原粉树脂具有１１０～２２０℃的结晶融峰，结晶度随聚合物温度的下降而线性增加，退火温度，退火时间等热处理条件对ＰＶＣ的重结晶行为有很大影响，在相同热处理条件下，增塑剂ＤＯＰ的加入使树脂的结晶度下降，聚合度越高的树脂，其结晶度越大。     

MOCVD热力学分析软件的开发

报导了最新开发的ＭＯＣＶＤ热力学分析软件－ＭＯＣＶＤＴＡ，它是一个采用目前比较 ＶＣＳ算法对ＭＯＣＶＤ的稳态系统进行单参数及双参数分析的软件。介绍了其功能，特点，使用方法以及适用条件，并且以Ａｓ－Ｈ系统及Ｇａ－Ａｓ－Ｃ－Ｈ系统为例进行了模拟，得到了很好的模拟结果。     

含活性基团硅氮烷先驱体的裂解

用ＴＧ－ＧＣ，ＩＲ，元素分析，ＸＲＤ研究ＭｅＳｉＨＣｌ２与ＭｅＳｉＶｉ（Ｖｉ：－ＣＨ＝ＣＨ２）Ｃｌ２共氨解产物的裂解过程。     

交联高聚合度聚氯乙烯的研究

研究了高聚合度聚氯乙烯（ＨＰＶＣ）的交联体系及其影响因素，实验结果表明，二硫代国甲基秋兰姆（ＴＭＴＤ）氧化锌，氧化镁组合的硫化体系可有效有交联ＨＰＶＣ，且交联效率大于过氧化二异丙苯交联体系，酸性物质（增塑剂，硬脂酸）将会降低ＴＭＴＤ／ＺｎＯ／ＭｇＯ硫化体系时ＨＰＶＣ的交联效率。     

超高分子量聚乙烯的滑动磨损性能与机理研究

用ＭＭ２００型磨损试验机测试了超高分子量聚乙烯（ｕｌｔｒａｈｉｇｈｍｏｌｅｃｕｌａｒｗｅｉｇｈｔｐｏｌｙｅｔｈｙｌｅｎｅ）的滑动磨损性能,考察了滑动速度与载荷对其磨损的影响,通过扫描电子显微镜对ＵＨＭＷＰＥ磨损表面形貌的观察,指出：在跑合期阶段,ＵＨＭＷＰＥ表面形成了一系列的脊;在严重磨损阶段,表面层发生了大范围的撕裂与断裂。热效应对其磨损的影响由ＰＥＤＳＣ７检测     

Study on sound absorption property of ramie fiber reinforced poly(l-lactic acid) composites: Morphology and properties

The effect of ramie fiber, flame retardant and plasticizer on sound absorption property of ramie fiber reinforced PLLA composites was investigated. We used press molding process to prepare the ramie fiber/PLLA composites, with short ramie fiber and ramie plain weave fabric as the reinforcement. The dispersivity of flame retardant ammonium polyphosphate (APP) was indirectly tested by thermogravimetric analysis (TGA). The result of sound absorption property measurement shows that the composites with short ramie fiber have better sound absorption property than the ramie fabric reinforced PLLA composites. And the addition of APP and plasticizer poly(butylene adipate-co-terephthalate) (PBAT) improves the sound absorption property of ramie fabric/PLLA composites. Moreover, morphological studies by scanning electron microscopy (SEM) demonstrate the micro-phase separation in the PBAT/PLLA composites and the porosity of the single ramie fiber bundle. The results suggest that these special structures are the main reason for the better sound absorption property.     

Characterization of epoxy resin-based anion-responsive polymers: applicability to chloride sensing in physiological samples

The potentiometric properties of an epoxy resin-based anion-responsive polymer and its feasibility as a chloride sensing membrane are described. The response mechanism of the epoxy resin-based membrane is studied by varying the types and contents of epoxy components (e.g., resin, hardener, diluent, and plasticizer). It is found that epoxy resins cured with polyamine-type hardeners have excellent characteristics as chloride-sensing membranes, in terms of their selectivity, stability, sensor lifetime, and adhesion for constructing an all-solid-state sensing device. In addition, effects of the diluent or plasticizer added in an epoxy resin/hardener system on the potentiometric behaviors are investigated. To demonstrate the practical analytical utility of the epoxy resin-based electrodes, chloride levels in various controls and biological specimens (e.g., human sera and whole blood) are determined with a flow-cell system.     

Impact of melt rheology on zein foam properties

Zein, the main protein fraction in maize, is left as a by-product from bio-ethanol production. The protein has been investigated as a material for a long time, but mainly in the form of films. In contrast, foamed zein is presented in this article. Zein foams may perhaps be used, e.g. as trays for biodegradable food packages or as scaffolds for tissue engineering. A batch method for manufacturing solid foams was successfully developed, the foams being manufactured by evaporation of solvent from zein resins. In order to be suitable for foam formation, a resin must possess gas-retaining properties, which can be predicted by extensional rheology. The presence of plasticizer in some of the resins decreased their extensional viscosity, and this in turn affected the foaming process. Although all the resins displayed strain-hardening behaviour, there was coalescence of pores in all the foams. Insufficient extensional viscosity resulted in the collapse of pore walls during foam expansion. Structure analysis showed, e.g. that most pores were elongated along the main axis of the mould in which the foams were manufactured. The plasticizer content in the resins had no significant effect on the mechanical properties of the foams.     

Magnetostrictive properties of epoxy resins modified with Terfenol-D particles for detection of internal stress in CFRP. Part 1: Materials and processes

Magnetostrictive particles like Terfenol-D are investigated with respect to their ability to detect internal stress, generated in carbon fibre-reinforced polymers (CFRP) in a non-destructive way. The results are presented in two parts. The first part elucidates the ideas for the preparation of dispersions based on these particles with high density in epoxy resins. There is particular focus on the effects of particle size and concentration. Different particle sizes in a range of 0–300?μm are selected by special separation techniques. The particle size distribution is controlled in dry state by laser diffraction method. Changing of the chemical composition, particularly by the oxidation of particles, is analysed by EDX. Use of a magnetic field is identified as a suitable means for the stabilisation of these high-weighted particle fractions dispersed in epoxy resins. The particle size distribution, as well as the alignment of particles, in the cured epoxy resins is investigated by SEM and light microscopy. The second part of the study covers the magnetostrictive properties of the modified epoxy resins which are quantified by the detection of internal stress in CFRP.     

Lignin/epoxy composites

This paper presents some possibilities for the use of lignin/epoxy resins in blends and composites with epoxy resins. A compatibility study was carried out by optical and electron microscopy, viscosimetric determinations and thermo-optical analysis in order to establish optimum synthesis conditions of molding mass (cast resins). Lignin/epoxy composites including various fillers (lead soap, alum earth, talc, chalk, sand, trihydrate aluminium oxide, glass fibers), plasticizer (dibutylphthalate and polyester C₆) and pigments (iron-oxide and titanium dioxide) have been obtained. Lignin/epoxy composites are characterized by good dielectric, mechanical and adhesive properties. These composite materials can be used in the electronics industry.     

Role of size scale of ZnO nanoparticles and microparticles on toxicity toward bacteria and osteoblast cancer cells

The present study describes the production of hyaluronan based porous microparticles by a semi-continuous gas anti-solvent (GAS) precipitation process to be used as a growth factor delivery system for in vivo treatment of ulcers. Operative process conditions, such as pressure, nozzle diameter and HYAFF11 solution concentrations, were adjusted to optimize particle production in terms of morphology and size. Scanning electron microscopy (SEM) and light scattering demonstrated that porous nano-structured particles with a size of 300 and 900 nm had a high specific surface suitable for absorption of growth factors from the aqueous environment within the polymeric matrix. Water acted as a plasticizer, enhancing growth factor absorption. Water contents within the HYAFF11 matrix were analyzed by differential scanning calorimetry (DSC). The absorption process was developed using fluorescence dyes and growth factors. Immunohistochemical analysis confirmed the high efficiency of absorption of growth factor and a mathematical model was generated to quantify and qualify the in vitro kinetics of growth factor release within the polymeric matrix. In vivo experiments were performed with the aim to optimize timed and focal release of PDGF to promote optimal tissue repair and regeneration of full-thickness wounds.     

高分子量聚氯乙烯的形态,流变与加工性能

采用程序升温Ｂｒａｂａｎｄｅｒ转矩－流变仪研究，比较了两种高分子量聚氯乙烯树脂（分子量相同）及其增塑体系在相同剪切应力作用下的熔融过程。采用毛细管流变仪和Ｂｒａｂａｎｄｅｒ挤出－流变仪研究了上述增塑体系的流变行为和挤出性能。结果表明，树脂颗粒的疏松程度越好，颗粒表面无皮膜包覆，粉粒破碎成聚结体和初级粒子的温度越低，这些微观层次的粒子相互粘连直至形成分子熔体的熔融温度越低，其增塑体系的熔融温度也越低     

高吸油性树脂的合成与性能

以甲基丙烯酸酯为单体，双烯化合物为交联剂，采用悬浮聚合方法合成高吸油性树脂。研究了单体结构、引发剂用量、交联剂用量及共聚单体配比对树脂性能的影响，并考察了高吸油性树脂对水面浮油的回收性能。     

颗粒形态对PVC增塑糊黏度的影响

用扫描电镜结合粒度分析方法,研究几种不同生产方法聚氯乙烯(PVC)糊树脂颗粒形态及其对增塑糊黏度性能的影响。结果表明,颗粒表面圆整,具有双峰粒度分布、次级粒子聚集松散的微悬浮法糊树脂所制增塑糊黏度最低,在1240 mPa.s~1390 mPa.s之间;其次是种子微悬浮法增塑糊;再次为种子乳液法增塑糊;颗粒形状不规则且表面粗糙,具有双峰粒度分布、次级粒子聚集较紧密的混合法增塑糊黏度最高,在1820 mPa.s~3050 mPa.s之间。对于增塑糊的存放稳定性,种子微悬浮法的效果最好,黏度变化率在6%以下;其次是微悬浮法和种子乳液法;混合法的最差,黏度变化率在41%以上。     

A Comparative Study of the In Vitro and In Vivo Release of Dexamethasone from a Spray-On Bandage and Timed Release Aerosol

The formulation of several dexamethasone topical delayed release aerosol preparations was studied. Ethylcellulose and tributyl citrate were the film-forming agent and plasticizer, respectively, for the spray-on bandage formulation. The aerosol timed release preparation contained dexamethasone microcapsules suspended in a fluorocarbon aerosol propellant by isopropyl myristate and fumed silica. Both preparations were evaluated using an in vitro method which measured the release of dexamethasone hourly for eight hours. In vitro studies showed that each of the formulations delayed the release of dexamethasone. In the in vivo tests aerosols were sprayed on the unabraded back area of rabbits and the increased 17 - hydroxycorticosteriod urine levels at 24, 48, and 72 hours indicated dexamethasone absorption. In vivo studies indicated that absorption did not occur with the timed release preparation containing dexamethasone microcapsules. However, dexamethasone from the spray-on bandage preparation was absorbed over 72 hours. A commercially marketed topical dexamethasone cream was used for comparison in evaluating the two experimental formulations; however, in vivo studies showed that no absorption occurred with this preparation.

In recent years, a great deal of work has been directed towards the application of medicated polymeric films or tissue adhesives onto the skin to treat minor dermatological problems or serious skin wounds. Among the factors to be considered are: incorporation of a specific active ingredient, the mode of application and the dosage form. Lange and Fang (1,2) developed spray-on bandages using water soluble resins and water as the solvent. Fischl (3) evaluated the effectiveness of a cyanoacrylate monomer in closing skin incisions without affecting wound healing. Bhaskar and Cutright (4) showed that butyl cyanoacrylate could be successfully used as a surface dressing while reducing the degree of inflammation. Sciarra and Gidwani (5,6) reported on the release of gentian violet from selected polymer and plasticizer combinations and established various polymer-plasticizer combinations which could be applied as an aerosol spray. Other studies (7,8) have shown that ethylcellulose and a thermoplastic polyamide resin have potential use in spray-on bandage formulations.

The results indicated that the anti-infectives were released from the films and the spray-on bandages reduced the degree of infection about the wound.

The process of microencapsulation has been applied to various industrial and medical uses. Microcapsules can be prepared so that the encapsulated material will be released slowly. There are various methods of microencapsulation including coacervation, phase separation, interfacial polymerization, an electrostatic method, and vacuum metalization and they have been successfully used with selected drugs (9-13).

The purpose of this study was to develop and evaluate different aerosol formulations containing a therapeutic agent which can be slowly released. In vitro and in Vivo systems were used to evaluate the release and absorption of the drug in the test animals.