聚合物挤出成型的新方法与新设备

本文论述一种聚合物塑化挤出成型的新方法与新设备,着重分析聚合物塑化挤出新概念和动态塑化挤出过程,并介绍塑料电磁动态塑化挤出设备的原理、结构、性能及特点。     

振动场强化聚合物塑化注射成型技术

介绍一种将机械振动力场引入聚合物塑化注射成型全过程的塑料电磁动态注射设备,提出振动力场强化聚合物塑化注射成型新概念,并论述塑料电磁动态塑化注射机的原理、结构及其应用.实验与生产表明:新型注射机对物料适应性广,与传统注射机比较在加工聚烯烃时能耗可降低50%以上,注射熔体温度可降低20℃以上,注射压力降低10%左右,制品力学性能提高15%以上,对无机填料填充体系的混合分散效果明显提高,并预示振动力场可改变注射充模熔体的流动状态.新型塑料注射机对聚合物加工工业的发展具有重大的科学和现实意义.     

塑料电磁动态塑化挤出机的挤出功率研究与模拟

本文采用自行修正的Tanner本构方程研究了塑料电磁动态塑化挤出机中熔体输送挤出功率对振动力场的响应。建立了振动力场作用下熔体输送挤出功率的理论模型,以此为基础模拟塑料电磁动态塑化挤出机的挤出功率,并进行了实验研究,结果表明理论模拟能够在一定范围内反映实际情况,为塑料电磁动态塑化挤出设备的设计和生产应用提供重要的理论指导依据。     

塑料电磁动态塑化挤出机加工制品的力学性能

本文采用塑料电磁动态塑化剂出机挤出的条料和吹塑的薄膜进行制样,并对其试样进行力学性能测试分析,结果表明,由于在挤出加工的全过程中引入了周期性振动力场,经塑料电磁动态塑化挤出机加工的制品的力学性能得到了改善和提高,对于PP和LDPE挤出试样,拉伸强度分别提高4.2%和4.7%,对HDPE吹塑膜,纵模向拉伸强度分别提高19.2%和37.4%。     

基于电磁动态塑化挤出的模头挤出特性的研究

本文以塑料电磁动态塑化挤出机上的圆截面模头为对象,研究了将振动力场引入聚合物塑化挤出全过程条件下圆截面模头的挤出特性,建立了圆截面模头脉动挤出特性的数学模型,并进行了实验研究,理论分析与实验结果趋向一致,从而揭示了振动力场引入聚合物塑化挤出全过程对圆截面模头挤出特性的影响规律。     

塑料电磁动态逆化挤出机的挤出功率研究与模拟

本文采用自行修正的Tanner本构方程研究了塑料电磁动态塑化挤出机中熔体输送挤出功率对振动力场的响应。建立了振支力场作用下熔体输送挤出功率的理论模型,以此为基础模拟塑料电磁动态逆化挤出设备的设计和生产应用提供重要的理论指导依据。     

超临界CO2/PVC微孔塑料连续挤出成型技术

阐述超临界CO2与聚氯乙烯（PVC）的相互作用，从微孔塑料成型过程的三个阶段出发，论证了用超临界CO2作为PVC微孔塑料发泡剂的可行性，并提出一种适合于PVC微孔塑料连续挤出生产的新的成型技术－－PVC微孔塑料的电磁动态挤出成型技术。可以预见，电磁动态挤出成型可降低加工温度、提高混合效果、易于生成大量细密泡孔，以及有效控制发泡过程。     

电磁动态塑化挤出机性能的研究

本文结合理论分析，着重从实验方面分析研究电磁动态塑化挤出机的挤出特性和混合特性，证明了这种新型挤出机具有挤出产量高、挤出稳定、挤出温度低、能耗低和混合效果好等优点。     

振动塑化挤出对聚烯烃片材性能的影响

利用塑料电磁塑化挤出机挤出聚烯烃片材，系统研究了挤出机螺杆轴向振动对聚乙烯挤出制品结构与性能的影响。采用DSC对挤出试样的结晶结构及形态进行分析。结果表明，振动塑化挤出使聚合物挤出试样结晶度提高，结晶完善，晶片之间的连接分子数量增加，因而制品的力学性能有所提高，特别在横向上表现明显。在适当的振动条件下，高密度聚乙烯（HDPE）试样的横向拉伸强度和冲击强度分别从22．68MPa和12．7kJ／m^2提高到了25．55MPa和23．5kJ／m^2；而聚丙烯（PP）试样横向拉伸强度和冲击强度则分别提高了20％和64％。     

振动力场下填充聚合物挤出过程研究

研究了利用塑料电磁动态塑化挤出机加工ＰＰ／ＣａＣＯ３和ＬＤＰＥ／ＣａＣＯ３时的动态挤出过程,探讨了振动力场对聚合物填充体系挤出过程扣影响规律和作用机理。结果表明,在一定的振动条件下,振动力场的作用使挤出压力减同功率降低,混合分散效果明显提高。     

电磁动态塑化挤出机成型机理,性能及展望

本文简述了挤出机发展史,着重介绍了新一代塑料电磁动态挤出机成型机理、性能及发展前景。     

Effect of Vibrating Extrusion on the Structure and Mechanical Properties of Isotactic Polypropylene

An electromagnetic dynamic plasticating extruder, invented by the authors, was used to prepare isotactic polypropylene (PP) sheets. Tensile and impact tests show that the extruded samples can simultaneously be reinforced and toughened along the flow and transverse directions in a moderate frequency and amplitude range. The microstructures of the obtained samples were characterized by differential scanning calorimetry (DSC), wide angle X-ray diffraction (WAXD), and scanning electron microcopy (SEM). The results indicate that the vibration plasticating extrusion affected the morphology of the PP extrudate, it especially resulted in finer spherulites, and move tie molecules, which account for the enhancement of the tensile strength and impact toughness of PP sheets in both extrusion and transversal directions.     

塑料电磁动态塑化挤出机的节能分析

本文从电磁动态塑挤机出引入振动场实现直接换能方式以后的宏观能量平衡分析入手，在理论上和实验上研究了分析新型挤出机的能分配情况，探讨了新型挤出机的能节原因，为优化设计提供了重要参考和理论依据。     

聚氯乙烯塑炼技术与机头内熔料流动模拟

为了满足聚氯乙烯型材挤出的需要,选择最佳的塑炼设备和确定合理的工艺控制参数。计算机模拟技术展示了熔料在机头内的流动状态。     

Structure and Properties of Vibrating Extruded High-Density Polyethylene Sheet

Summary The effect of vibration frequency and vibration amplitude on the microstructure and mechanical properties of high-density polyethylene (HDPE) sheets, obtained through electromagnetic dynamic plasticating extruder, were studied systematically. The mechanical properties, characterized by tensile and impact strengths, have been tested along the flowing and transverse directions (MD&TD). The mechanical tests show that the tensile strength and impact toughness, especially in TD, were much improved under the reciprocating axial vibration. Differential scanning calorimetry (DSC), scanning electron microcopy (SEM) and wide angle X-ray diffraction (WAXD) were executed to analyze the microstructure of the samples. The results indicate that the vibration extrudate has higher crystallinity, perfect crystallite, and strong inter-spherulite ties, which account for enhancement of the mechanical properties of sheets, compared to conventional static extrusion.     

Effect of vibration extrusion on the structure and properties of high‐density polyethylene pipes

BACKGROUND: The axial strength of a plastic pipe is much higher than its circumferential strength due to the macromolecular orientation during extrusion. In this work, a custom‐made electromagnetic dynamic plasticating extruder was adopted to extrude high‐density polyethylene (HDPE) pipes. A vibration force field was introduced into the whole plasticating and extrusion process by axial vibration of the screw. The aim of superimposing a vibration force field was to change the crystalline structure of HDPE and improve the molecular orientation in the circumferential direction to obtain high‐circumferential‐strength pipes. RESULTS: Through vibration extrusion, the circumferential strength of HDPE pipes increased significantly, and biaxial self‐reinforcement pipes could be obtained. The maximum increase of bursting pressure and tensile yield strength was 34.2 and 5.3%, respectively. According to differential scanning calorimetry and wide‐angle X‐ray diffraction measurements, the HDPE pipes prepared by vibration extrusion had higher crystallinity, higher melting temperature, larger crystal sizes and more perfect crystals. CONCLUSION: Vibration extrusion can effectively enhance the mechanical properties of HDPE pipes, especially the circumferential strength. The improvement of mechanical properties of HDPE pipes obtained by vibration extrusion can be attributed to the higher degree of crystallinity and the improvement of the molecular orientation and of the crystalline morphology. Copyright © 2008 Society of Chemical Industry     

Mechanochemical Treatment of CaC03 for Reducing Hyprophylicity

The article discusses the modification of CaCO₃ hydrophylicity by mechanochemical methods, in view of its compatibilization with hydrophobic polymeric matrices. The observation was made that by ultrahigh-speed stirring of the solutions of polybutadiene and acrylic acid—in which CaCO₃ powder has been suspended—as well as by vibratory milling of CaCO₃ in the presence of isoprene, modifications in the hydrophylicity of the anorganic particles occur. The treatment's efficiency depends on two process parameters: duration and monomer/charge ratio.     

Insect antifeedant properties of anthranoids from the genusVismia

Vismiones and ferruginins, representatives of a new class of lypophilic anthranoids from the genusVismia were found to inhibit feeding in larvae of species ofSpodoptera, Heliothis, and inLocusta migratoria.