酯化釜设备故障时的工艺控制

介绍了酯化釜设备故障情况,如酯化釜液位计故障,酯化反应泵机封EG内漏及对生产的影响。指出了在故障情况下稳定生产的对策,包括利用相关工艺点变化间接控制酯化二室液位及酯化机封泄露时羧基的控制。     

The use of SVM-FFA in estimating fatigue life of polyethylene terephthalate modified asphalt mixtures

To predict fatigue life of Polyethylene Terephthalate (PET) modified asphalt mixture, various soft computing methods such as Genetic Programming (GP), Artificial Neural Network (ANN), and Fuzzy Logic-based methods have been employed. In this study, an application of Support Vector Machine Firefly Algorithm (SVM-FFA) is implemented to predict fatigue life of PET modified asphalt mixture. The inputs are PET percentages, stress levels and environmental temperatures. The performance of proposed method is validated against observed experiment data. The results of the prediction using SVM-FFA are then compared to those of applying ANN and GP approach and it is concluded that SVM-FFA leads to more accurate results when compared to observed experiment data.     

Numerical simulation of the wire‐pinning process in PET film casting: Steady‐state results

Poly(ethylene terephthalate) (PET) film casting involves melt flow through a slot die, across a small span, and onto a fast moving quench drum. In the “wire‐pinning” casting process, a thin electrified wire close to the line of contact with the drum creates a strong pinning force that delays air entrainment to higher line speeds. Nonuniform wetting of the die lips by the extruded melt is thought to be responsible for the formation of streaks, a defect in the machine direction. A finite element model of the film casting process with wire pinning was developed to assist in understanding what causes significant wetting of the lips and whether this can be avoided by electrostatic pinning. The solution of the governing equations provide the location of the static and dynamic contact lines, thus finding the wetting and pinning points in the process. The simulations investigate the sensitivity of the static wetting line locations on the die lands to the imposed values of static contact angle and die‐lip gap. It was found that while the contact angle has a small effect on the extent of die‐lip wetting within the parameter ranges examined, there is a considerable chance that the feed slot surfaces can be dewetted. This seems to be the greatest danger for causing streaks rather than excessive wetting of the die lands. © 2011 American Institute of Chemical Engineers AIChE J, 2012     

原料PTA对PET色相影响的分析

从原料PTA品质指标中的色相、粒径、总金属含量等指标入手,分析其指标对PET色相的影响,确定要想生产出色相好的PET切片产品,需要使用优质的原料PTA。     

用于预警和安保系统的新型发光复合高分子纤维

新型发光、无机和有机纳米型染料主要用于聚对苯二甲酸乙二醇酯（PET）纤维的制备。PET纤维是制作用于预警和安保系统的纤维织物的原材料。具有发光性质的纳米染料的制备方法主要有两种：一种为自下而上,沉淀法合成;另一种为自上而下,通过反应型研磨得到。下述的纳米染料是硫化锌（ZnS）,同时还掺杂有铜或锰、铝酸锶,还可掺杂铕和镝。此外,还对有机染料和颜料（醛连氮和二萘嵌苯）进行研究,还将其包裹于硅纳米粒子中并进行相关研究。制得的纳米粒子混入高分子熔体中,通过熔融挤出得到成品丝。该过程中所使用的纳米颜料可混入母粒中,也可制成液状使用。最后进行成品丝变形工艺研究,并加工成纺织面料。纳米发光颜料的加入实现了低染料剂量下的高发光性。与已投入使用的传统体系相比,采用纳米发光颜料的体系具有更好的光、热和湿牢度。     

多影像成像技术联合应用对早期周围型肺癌的诊断价值

目的 综合分析增强CT、高分辨率CT（HRCT）及18F-FDG PET/CT影像学资料,以评价不同影像学方法对早期周围型肺癌的诊断价值.方法 对32例临床疑为早期周围型肺癌患者分别行动态CT增强、HRCT、PET/CT检查.以病理结果为最终诊断的金标准,计算这3种方法及两两联合检查对诊断早期周围型肺癌的敏感度、特异度和准确率.结果 3种检查方法中PET/CT的敏感度、特异度和准确率最高,两两联合检查中PET/CT和增强CT的敏感度、特异度、准确率较高,且优于任一种单一检查方法.结论 多种影像成像技术联合应用,可提高早期周围型肺癌诊断的准确率,尤其是PET/CT和增强CT的联合应用.     

烷基次膦酸铝阻燃剂的合成及其在PET中的应用

为了开发阻燃性优良的聚对苯二甲酸乙二酯(PET)材料,扩大该工程塑料的应用范围,合成了一种含P—C键的新型烷基次膦酸铝,采用傅立叶变换红外光谱、31P核磁及元素分析等证实了所合成的产品与目标产物结构特征一致,并将其作为阻燃剂对PET进行阻燃改性,通过垂直燃烧、极限氧指数和热分析等测试,研究了烷基次膦酸铝对PET材料阻燃性能的影响。结果表明,自制烷基次膦酸铝具有良好的阻燃效果,当添加量为15%时,可以使材料达到UL94 V–0阻燃级别,极限氧指数为32.4%;与市售次膦酸铝产品的各项性能基本相当,有望成为一种新型环保阻燃剂应用于PET中。     

氯化亚锡和纳米二氧化硅对PET材料表面亲水性影响

目的 提高PET材料的表面亲水性.方法 氯化亚锡与PET共混成膜后,采用共混接枝法,在共混膜表面接枝氨基化改性的纳米二氧化硅,制备出强亲水的PET材料.采用静态接触角、傅里叶变换红外光谱仪、原子力显微镜测试手段对PET材料表面进行表征.结果 氨基化改性的纳米二氧化硅能够成功接枝在氯化亚锡与PET共混材料表面.当氯化亚锡质量分数为0.3%时,共混膜接触角由98°下降到74.5°.共混膜接枝氨基化改性的纳米二氧化硅溶液20 h时,PET材料表面接触角由74.5°下降到7.8°,亲水性得到了极大提高.接枝膜浸泡于蒸馏水10 d后,PET材料表面接触角由7.8°上升至34.9°.结论 氯化亚锡与PET材料共混,接枝氨基化改性的纳米二氧化硅后极大地提高了PET材料表面的亲水性.     

PET薄膜的亲水改性研究

目的 探索对聚对苯二甲酸乙二醇酯(PET)薄膜亲水改性的制备工艺,研究其是否能有效提高PET薄膜表面的亲水性。方法 将PET薄膜裁剪成1 cm×4 cm的矩形样条,样条放入盛有无水乙醇的离心管中超声清洗,经烘干后再放入叔丁基过氧化氢(TBHP)溶液中进行引发反应,引发完成的PET薄膜样条依次用无水乙醇、水超声清洗后放入PVP溶液进行改性,最后超声清洗并烘干放置24 h进行接触角测试与红外光谱测试,分别评价PET薄膜的亲水性与表面成分变化。结果 使用不同PVP进行改性,PVP-K90对PET薄膜的改性效果最佳,接触角下降最明显,其接触角为21.3°。研究不同浓度TBHP对接触角的影响,随着TBHP浓度增加,接触角逐渐减小,TBHP浓度为1%时,其接触角为28°。探究不同浓度PVP-K90对接触角的影响,随着PVP-K90浓度增加,接触角呈现先减小后略有增大的变化趋势,PVP-K90浓度为5%时达到最小值(24.2°)。最佳配方和工艺为：5%PVP-K90+1%TBHP,温度80℃,转速600 r/min,反应时间1 h。PET薄膜的接触角从改性前的81.7°下降到改性后的29.5°,亲水...