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％。     

振动力场下聚合物塑化挤出技术研究

介绍玫种将电磁场引起的机械振动力场引入聚合物塑化挤出全过程的塑料电磁动态塑化挤出设备,讨论了它的原理、结构及应用,实验与生产表明,塑料电磁动态塑化挤出设备在加工聚烯烃时能耗降低２０％～５０％,挤出熔体温度降低２０℃以上,制品拉伸强度提高１６％以上,对无机填料充体系的兴旺聚散效果提高。     

熔融挤出工艺对EPDM/PP热塑性弹性体性能影响

研究了在原料配比、加工工艺(硫化温度、螺杆转速)、硫化体系一致的情况下,分别采用熔融挤出一步法和两步法动态硫化制得的三元乙丙橡胶(EPDM)/聚丙烯(PP)热塑性弹性体物理力学性能。实验结果表明,与一步法相比,两步法制得的试样加工流动性较好,熔体流动速率提高1 g/10 min;力学性能较好,拉伸强度、拉伸屈服强度、冲击强度分别增加1.95,2.39,1.55 MPa;交联效果较好,硬度提高2度、压缩永久变形降低3.67%。     

电磁动态注射机振动参数对PP力学性能的影响

采用电磁动态注射机注塑成型PP试样,并对其进行拉伸强度、冲击强度和DSC测试,探讨振动频率和振幅对制品力学性能的影响。结果表明:施加振动后,拉伸强度和冲击强度提高;熔点向高温漂移,有利于结晶完善程度的提高。对PP注塑料,电磁动态注塑成型时最佳的振动参数范围为f=3～9Hz,A=0 10mm～0 40mm。     

三螺杆动态塑化混炼加工PP/硅灰石力学性能及界面的研究

硅灰石填充 PP 经三螺杆动态塑化混炼加工后,将粒料制成试样并进行力学性能测试和扫描电镜断面分析。实验研究了不同振动参数对 PP/硅灰石力学性能和断面微观结构的影响。结果表明,与稳态相比,动态(引入振动)加工条件下试样的冲击强度、拉伸强度、断裂伸长率和弯曲强度均有显著提高,最大分别提高了10.7%、10.2%、51.3%和18.6%;对在振动频率 f=10 Hz、振幅 A=105 μm动态塑化混炼加工条件下试样的扫描电镜断面分析表明,PP/硅灰石材料中硅灰石的粒径变小并趋于一致,分散分布均一,与 PP 结合界面得到加强。     

机械激振式挤出机制备LDPE的结构与性能

采用振动挤出和稳态挤出的方法制备LDPE试样。探讨振动力场的振动频率和振幅对管材微观结构、力学性能、热学性能和微观取向程度的影响。结果表明:振动力场的施加能够增加聚合物结晶度且提高晶区取向程度。与相同加工条件下的稳态挤出试样相比,振动挤出的LDPE试样的拉伸强度和拉伸模量提高,断裂伸长率降低。     

微纳层叠挤出技术对聚氯乙烯结晶性能的影响

采用Moldex3D软件对自主发明设计的微纳层叠装置剪切场进行分析,发现沿着挤出方向,剪切速率先升高后降低;利用微纳层叠装置在挤出过程中对聚合物熔体产生的持续剪切作用,制备了1层、9层、81层3种具有不同层数的聚氯乙烯(PVC)片材。通过超声波测试、傅里叶变换红外光谱分析、万能试验机试验分别对PVC片材的取向度、相对结晶度和力学性能进行了研究。结果表明,沿挤出方向9层、81层试样的取向度比1层试样分别提高了9.82%,15.08%;9层、81层试样的相对结晶度比1层试样分别提高了4%,5.9%;挤出方向拉伸强度分别提高了11.15%,26.16%。     

微纳叠层挤出成型方法对PP材料性能的影响

利用微纳叠层挤出成型设备制备了1层、9层和81层的单一聚烯烃PP材料,且成型设备由实验室自主研发。通过对其力学性能、DSC和热台偏光显微镜的测试,研究了微纳叠层挤出成型方法对PP材料性能的影响。研究结果表明:通过扭转叠层单元所产生的剪切场使高分子链的取向度和材料的结晶度均得到大幅度提升,晶粒尺寸明显细化;9层、81层试样的结晶度较1层试样分别提高了2.70%、7.57%;晶粒尺寸较1层相比分别缩小了30、42μm;在挤出方向上,9层、81层试样的拉伸强度较1层分别提高了6.73%、16.18%;在垂直于挤出方向上,9层、81层的横向拉伸强度较1层分别提高了10.30%、17.15%,类似于双轴拉伸的效果。     

动态三螺杆加工超细碳酸钙填充聚丙烯研究

以超细碳酸钙填充聚丙烯作为研究对象,经三螺杆动态加工后,将粒料制成试样并进行力学性能测试和扫描电镜分析.研究了不同振动参数对共混物力学性能和对截面形态结构的影响规律.结果表明,与稳态相比,动态(引入振动力场)加工条件下试样的冲击强度、拉伸强度和断裂伸长率都有显著的提高.     

振动力场对m-PE-LLD薄膜拉伸强度的影响

使用电磁动态吹膜机组加工m-PE-LLD薄膜,将振动力场引入到塑化挤出的全过程,考察了振动力场对m-PE-LLD薄膜拉伸强度的影响。研究发现,振动力场的加入使m-PE-LLD吹塑薄膜的横向强度增大、纵向强度减小,纵、横向拉伸强度趋于均匀。振动力场对PE-LD和PE-HD的拉伸强度的影响具有相似的规律,初步的分析机理认为:振动力场引入后,聚合物熔体同时受到轴向和周向的作用力,分子链会沿两个作用力的方向进行排列,形成网格化排列的结构,从而使薄膜纵、横向强度趋于均一。     

振动力场下PP增强管材的制备及性能研究

采用电磁动态塑化挤出机挤出聚丙烯（PP）管材,通过爆破压力测试、拉伸性能测试、差示扫描量热（DSC）分析和X射线衍射（XRD）分析研究了振动频率和振幅对PP管材结构与力学性能的影响。力学性能测试结果表明,振动挤出PP管材的周向强度有了显著提高,实现了管材的双向自增强。与稳态挤出的PP管材相比,振动挤出PP管材的爆破压力最大提高了27．03％,轴向拉伸屈服强度最大提高了7．3％。DSC分析和XRD分析表明,振动挤出的PP管材结晶度提高,熔点升高,结晶完善,晶粒变小,有利于管材力学性能的提高。     

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     

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.     

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.     

电磁动态注塑对等规聚丙烯增韧和增强研究

利用普通注射成型和电磁动态注塑机注射成型制备等规聚丙烯试样，并对其进行拉伸强度、冲击强度、差示扫描量热仪（DSC）和广角X射线衍射（WAXD）测试。对动态与稳态注射成型聚丙烯制品的力学性能进行了比较，并结合微观测试结果，深入探讨了制品微观结构与力学性能之间的关系。力学测试结果表明，动态成型制品的拉伸性能和冲击性能比稳态加工条件下都有所提高，尤其是制品冲击性能的提高幅度可以达到40％以上，实现了对制品的同时增强和增韧。DSC和WAXD测试表明，动态成型制品的结晶比稳态制品完善，并且晶粒尺寸也小于稳态制品。经过理论分析，认为结晶情况的改善是制品拉伸强度提高的原因，而晶粒细化则大幅度提高了制品的冲击强度。     

振动力场下HDPE/CaCO3复合材料的拉伸性能

使用电磁动态塑化挤出机,对HDPE／CaCO,复合材料的挤出片材做横向和纵向拉伸性能研究。振动力场能够有效地改善HDPE／CaCO,片材的拉伸强度和拉伸断裂伸长率,在本实验范围内,与稳态挤出制品相比,片材的横向和纵向拉伸强度分别提高了16．4％和15．6％,横向和纵向拉伸断裂伸长率分别提高了38．9％和44．0％;振动对材料横向的影响比对纵向更具有规律性。     

动态挤出PP板材制品的结构与性能

利用电磁动态塑化挤出机挤出PP板材制品,并对其聚集态结构与力学性能进行测试分析。结果表明在挤出过程中引入振动力场,可以改变PP制品的聚集态结构,从而使其力学性能得到改善。     

Effect of vibration parameters of electromagnetic dynamic plastics injection molding machine on mechanical properties of polypropylene samples

Dynamic injection processing experiments have been carried out on polypropylene using the self‐made electromagnetic dynamic plastics injection molding machine, and the effects of the vibration force field on mechanical properties of molding samples are studied, namely, the influence of vibration frequency and vibration amplitude on the mechanical properties of samples are researched by using tensile testing, impact testing, differential scanning calorimeter (DSC) and scanning electronic micrograph (SEM) techniques. The results show that the tensile strength and impact strength are both enhanced and the melting point shifts toward the higher temperature, which facilitates the perfection of crystal. The best vibration parameters for processing polypropylene using electromagnetic dynamic plastics injection molding machine are that frequency is from 3 to 9 Hz and amplitude is from 0.1 to 0.4 mm. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 972–976, 2006     

衣架式机头动态挤出PP的力学性能

采用衣架式机头动态挤出PP试样,并对其进行拉伸强度、冲击强度和DSC测试,探讨振动频率和振幅对制品力学性能的影响。结果表明：振动的引入,有利于提高制品纵横两向的拉伸强度和冲击强度,并且存在最佳振动参数范围,当振幅0．1mm时,方向的力学性能改善效果最显著;而当频率为15Hz时．方向力学性能改善效果最为明显;制品熔点向高温迁移,吸热焓与结晶度也得到提高。