Ultrasound-Assist Extrusion Methods for the Fabrication of Polymer Nanocomposites Based on Polypropylene/Multi-Wall Carbon Nanotubes

Isotactic polypropylenes (iPP) with different melt flow indexes (MFI) were used to fabricate nanocomposites (NCs) with 10 wt % loadings of multi-wall carbon nanotubes (MWCNTs) using ultrasound-assisted extrusion methods to determine their effect on the morphology, melt flow, and electrical properties of the NCs. Three different types of iPPs were used with MFIs of 2.5, 34 and 1200 g/10 min. Four different NC fabrication methods based on melt extrusion were used. In the first method melt extrusion fabrication without ultrasound assistance was used. In the second and third methods, an ultrasound probe attached to a hot chamber located at the exit of the die was used to subject the sample to fixed frequency and variable frequency, respectively. The fourth method is similar to the first method, with the difference being that the carbon nanotubes were treated in a fluidized air-bed with an ultrasound probe before being used in the fabrication of the NCs with no ultrasound assistance during extrusion. The samples were characterized by MFI, Optical microscopy (OM), Scanning electron microscopy (SEM), Transmission electron microscopy (TEM), electrical surface resistivity, and electric charge. MFI decreases in all cases with addition of MWCNTs with the largest decrease observed for samples with the highest MFI. The surface resistivity, which ranged from 10¹³ to 10⁵ Ω/sq, and electric charge, were observed to depend on the ultrasound-assisted fabrication method as well as on the melt flow index of the iPP. A relationship between agglomerate size and area ratio with electric charge was found. Several trends in the overall data were identified and are discussed in terms of MFI and the different fabrication methods.     

Prospective multicenter clinical trial of Uretex Sup for surgical treatment of stress urinary incontinence

AIM: To evaluate in a prospective multicenter study the efficacy and safety of the suburethral support Uretex (Sofradim, Trevoux, France) delivered by a suprapubic approach in the treatment of female stress urinary incontinence. METHODS: Between March 2002 and March 2003, 57 patients were treated for stress urinary incontinence with Uretex. Preoperative evaluation included urodynamic examination and questionnaires (symptoms and quality of life, Contilife). Forty patients had pure stress urinary incontinence and 17 mixed urinary incontinence. No associated procedure was performed. The objective cure rate was evaluated by clinical examination and pad-test, and the subjective cure rate was assessed through questionnaires at 1, 3 and 12 months. RESULTS: The mean follow-up was 13 months (range 11-24 months). During follow up, chronic urinary retention requiring a tape section occurred in one patient, and in another patient a delay of vaginal healing was followed by a sling exposure and resection at 4 months. No infection or urethral erosion was reported. The objective cure rate was 96.2%, and the subjective cure rate was 79.2%; four patients reported low leakage on stress and nine patients complained of urge incontinence (four de novo and five persistent). CONCLUSION: The suprapubic Uretex Sup procedure is a safe and effective treatment for women with stress urinary incontinence.     

单丝聚丙烯合成非吸收齿状线在美容整形应用中并发症的防治及应用改进

目的探讨单丝聚丙烯合成非吸收齿状线在美容整形中的并发症产生的原因及应用方法及技术的改进。方法对近两年的单丝聚丙烯合成非吸收齿状线在美容整形中的应用进行总结与分析。结果改进应用方法后，并发症明显减少，效果加强。结论单丝聚丙烯合成非吸收齿状线在美容整形中应用得当，可减少并发症、取得显著效果。     

Silicone-Coated Polypropylene Hollow-Fiber Oxygenator: Experimental Evaluation and Preliminary Clinical Use

Background. A membrane oxygenator consisting of a microporous polypropylene hollow fiber with a 0.2-μm ultrathin silicone layer (cyclosiloxane) was developed. Animal experimental and preliminary clinical studies evaluated its reliability in bypass procedures.

Methods. Five 24-hour venoarterial bypass periods were conducted on dogs using the oxygenator (group A). In 5 controls, bypass periods were conducted using the same oxygenator without silicone coating (group B). As a preliminary clinical study, 14 patients underwent cardiopulmonary bypass with the silicone-coated oxygenator.

Results. Eight to 16 hours (mean, 12.2 hours) after initiation of bypass, plasma leakage occurred in all group B animals, but none in group A. The O₂ and CO₂ transfer rates after 24 hours in group A were significantly higher than at termination of bypass in group B (p < 0.005 and p < 0.03, respectively). Scanning electron microscopy of silicone-coated fibers after 24 hours of bypass revealed no damage to the silicone coating of the polypropylene hollow fibers. In the clinical study, the oxygenator showed good gas transfer, acceptable pressure loss, low hemolysis, and good durability.

Conclusions. This oxygenator is more durable and offers greater gas transfer capabilities than the previous generation of oxygenators.     

应力场下固—液相分离制备微孔聚丙烯中空纤维膜

将聚丙烯和石蜡油的混合物熔融挤出,使之在较高的应力场下冷却和相分离,得到了弹性聚丙烯中空纤维。这种部分结晶的弹性纤维可能具有平行排列的片晶结构,石蜡油存在于片晶之间。将石蜡油提取掉后稍加拉伸即可得到透气性很好的微孔中空纤维渗透膜。     

动态硫化PP／EPDM强化增韧机理的动态力学研究

采用动态力学试验方法,研究了不同ＥＰＤＭ含量的动态硫化和简单共混两种ＰＰ／ＥＰＤＭ材料动态力学响应的差异及其特征。结果显示：与简单共混ＰＰ／ＥＰＤＭ相比,动态硫化ＰＰ／ＥＰＤＭ具有ΔＴｇ小,内耗峰扩宽程度大,低温和室温内耗峰强度高,所处温度低,６０－７０℃时内耗峰强度发生高低变位,在ＥＰＤＭ相的α转变以下还显示β和γ次级转变等特性。     

Compatibility and stability of bryostatin 1 in infusion devices

Bryostatin 1 is currently in phase II clinical trial sponsored by the National Cancer Institute as an anticancer chemotherapeutic agent. Bryostatin 1 for injection was supplied in a dual pack containing a drug vial and a diluent vial and was manufactured by Ben Venue Laboratories, Inc (Bedford, OH). The stability and compatibility of the bryostatin 1-PET formulation, diluted to 1 and 10 ug/mL in saline and benzyl alcohol preserved saline, with polypropylene (PP) and polyvinyl chloride (PVC) bags at room temperature (27°C) were studied. All experiments were conducted in triplicate and analyses were performed using a validated, stability-indicating, high performance liquid chromatography (HPLC) assay.Bryostatin 1 solutions were compatible with PP bags. At both concentrations and with both salines, the bryostatin content remained unchanged during the 28-day storage period, benzyl alcohol concentration in the preserved saline solutions also remained relatively constant. In PVC bags, however, a decrease in bryostatin 1 concentrations without generation of decomposition products was observed at both dilutions and with both salines during the 28-day storage. A decrease in benzyl alcohol concentration in the preserved saline was also observed. While no diethylhexylphthalate (DEHP) leakage into the solution was observed in PP bags, DEHP leakage in PVC infusion bags was observed on day 2 of storage which increased with storage time and leveled off on day 6. The amount of DEHP leached into drug solution is dependent on the drug concentration. This study suggests bryostatin-PET formulation diluted with preserved saline can be used for long-term (4 week) intravenous administration using PP infusion bags, but not with PVC bags.     

质量提取法测试直立式聚丙烯输液袋包装的葡萄糖注射液密封完整性

目的 建立质量提取法对直立式聚丙烯输液袋包装的葡萄糖注射液(规格：250 mL:12.5 g)的密封完整性进行测试。方法 进行方法参数设定及系统适用性、检出限与检测范围、耐用性、精密度等方法学验证,以及对直立式聚丙烯输液袋包装的葡萄糖注射液(规格：250 mL:12.5 g)加速0、3、6个月样品的密封完整性进行测定。结果 质量提取法方法检出限为3μm;精密度(RSD)为2.07%～5.60%。结论 本次研究采用的质量提取法可以用于直立式聚丙烯输液袋的密封完整性测试,该方法灵敏度较高,操作简单,结果真实可靠。     

Analysis of Mechanical Properties Related to Fiber Length of Closed-Loop-Recycled Offcuts of a Thermoplastic Fiber Composites (Organo Sheets)

Increasing demand for energy-efficient means of transport has steadily intensified the trend towards lightweight components. Thermoplastic glass fiber composites (organo sheets) play a major role in the production of functional automotive components. Organo sheets are cut, shaped and functionalized by injection molding to produce hybrid components, such as those used in car door modules. The cutting process produces a considerable amount of production waste, which has thus far been thermally recycled. This study develops a closed mechanical recycling process and analyzes the different steps of the process. The offcuts were shredded using two shredding methods and implemented directly in the injection-molding process. Using tensile tests and impact bending tests, the material properties of the recycled materials were compared with the virgin material. In addition, fiber length degradation via the injection-molding process and the influence of the waterjet-cutting process on the mechanical properties are investigated. Recycled offcuts are both comparable to new material in terms of mechanical properties and usability, and are also economically and ecologically advantageous. Recycling polypropylene waste with glass fiber reinforcement in a closed loop is an effective way to reduce industrial waste in a sustainable and economical production process.     

异氰酸酯偶联剂对木塑复合材料的影响

目的以木材纤维和废旧聚丙烯塑料为主要原料,通过热压制板工艺制造木材纤维-热塑性聚合物复合材料。方法通过对热压制板工艺中废旧聚丙烯塑料的含量、异氰酸酯用量、热压时间、热压温度等主要工艺参数的对比,找出最佳参数比。结果制定出最佳参数比。结论热压制板的物理力学性能满足中密度板国家标准的要求。