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。     

全程动态注塑对HIPS制品力学性能影响研究

在振频0-12 Hz,振幅0-0．28 mm的范围内,使用自主发明的电磁动态注塑机研究了振动参数的变化对 HIPS制品力学性能和冲击断面形态结构的影响。结果表明:制品的力学性能对振动参数的响应不完全是一个单调趋势,而是存在一个最佳的响应范围。电磁动态注塑机引入的全程动态注塑过程能够同时提高制品的拉伸性能和冲击性能,冲击强度和拉伸强度最大提高幅度分别为20％和14．4％。而制品的冲击断面微观结构也表明,全程动态注塑过程能有效改善HIPS制品的微观结构。     

全程动态注塑对HIPS制品力学性能影响研究

在实际生产的条件下，在振频0-12Hz，振幅0—0.28mm范围内研究了振动参数的变化对HIPS制品力学性能和；中击断面形态结构的影响。揭示了制品力学性能对振动参数的响应不完全是一个单调趋势，而是存在一个最佳的响应范围。全程动态注塑过程能够同时提高制品的拉伸强度和冲击强度，冲击强度和拉伸强度最大提高分别为20％和14．4％。     

全程动态注塑对HDPE制品力学性能的影响

在实际生产条件下，在振频0～12Hz、振幅0～0．28mm范围内研究了振动参数对HDPE制品的力学性能和冲击断面形态结构的影响。结果表明：制品的力学性能对振动参数的响应并不是单调趋势，而是存在一个最佳的响应范围；全程动态注塑过程能提高制品的拉伸和冲击性能．其中冲击强度提高尤其明显，最大可提高33％。     

塑料动态注射充模过程工艺参数的优化研究

运用了Taguchi方法研究了PP动态注射成型工艺参数对制品性能的影响。研究结果表明，在注射速度、保压压力、振动频率与振幅这四个工艺参数中，在所设定的工艺范围内，对制品性能影响比较明显的是振动频率与振幅。PP试样的冲击强度随振动频率改变而改变，且在10Hz左右存在一个最佳状态，冲击强度可以增加42％。拉伸性能随着振幅的增加基本上呈上升的趋势，极限拉伸应力最大增加8％，弹性模量最大可增加18．7％。在优化的振动工艺参数下，即在1～5Hz的频率段振幅对制品的拉伸性能的影响较之明显，在7～15Hz的频率段振动频率对制品的冲击性能的影响较显著。     

全程动态注塑对PS制品力学性能影响的研究

在实际生产条件下,在振频0~12Hz、振幅0~0.30mm范围内研究了振动参数对聚苯乙烯(PS)制品的力学性能和冲击断面形态结构的影响。结果表明,制品的力学性能对振动参数的响应并不是单调趋势,而是存在一个最佳的响应范围;全程动态注塑过程能提高制品的拉伸和冲击性能,其中冲击强度提高尤其明显,最大可提高28.6%。     

全程振动注塑对PP力学性能影响的研究

以实际生产条件为前提,在频率0～12Hz、振幅0～0．28mm范围内研究了振动对聚丙烯(PP)力学性能和冲击断面形态结构的影响。结果表明,PP的力学性能对振动参数的响应并不完全是一个单调趋势,而是存在一个最佳的响应范围;全程振动注塑能够同时提高PP的拉伸强度和冲击强度,最大增幅分别为17％和27％。     

全程振动注塑对PP力学性能影响研究

以实际生产条件为前提，在频率为0～12Hz、振幅为0～0．28mm范围内研究了振动对聚丙烯（PP）力学性能和冲击断面形态结构的影响。结果表明，PP的力学性能对振动参数的响应并不完全是一个单调趋势，而是存在一个最佳的响应范围；全程振动注塑能够同时提高PP的拉伸强度和冲击强度，最大增幅分别为17％和27％。     

振动改善全同立构聚丙烯注塑试样的力学性能

为了研究振动场对全同立构聚丙烯力学性能的影响，研制了压力振动注射装置，研究了不同熔体温度下，振动频率、振动压力对iPP F401注塑试样的拉伸强度、冲击强度和断裂伸长率的影响，并进行了WAXD和DSC测试。结果表明：振动除了提高试样结晶度外，还会诱导晶型的变化，即除α晶，还有β晶生成。随着振动频率和振动压力的增加，振动试样的拉伸强度和冲击强度得到明显改善，其最大增幅分别为26．1％和168％。     

GF增强PA66复合材料注塑制品熔接痕强度改善研究

通过在聚酰胺66 (PA66)中加入不同含量玻璃纤维,进行了玻纤增强PA66复合材料注塑制品熔接痕强度变化规律的研究。在获取最佳玻纤含量的情况下,利用研制的熔接痕样条振动模具进行了不同振动参数条件下玻纤增强PA66复合材料制品熔接痕强度变化规律的研究。研究结果表明,在本实验条件下,不同含量玻纤增强PA66复合材料注塑制品的熔接痕强度存在最佳值,即当玻纤质量分数为40%时,熔接痕强度达到最大值;在玻纤质量分数为40%时,引入振动力场能进一步提高制品熔接痕强度,且振动参数存在最佳值：当振动频率为40 Hz时,制品拉伸强度达到最大值,当振动频率为50 Hz时,制品弯曲强度、冲击强度均达到最大值。在振动力场的作用下,随着频率加大,PA66基体与玻纤均更易沿着熔体流动方向移动,玻纤在制品熔接痕区域相互穿插形成交织结构,从而提升熔接强度。     

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 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     

Mechanical properties and morphological behavior of calcium carbonate‐filled polypropylene in dynamic injection molding

A custom‐made electromagnetic dynamic injection molding machine was adopted to study the mechanical properties and morphological behavior of calcium carbonate‐filled polypropylene (PP) in a dynamic injection molding process. The influence of vibration amplitude and frequency on the mechanical properties and morphological behavior of samples was investigated using tensile tests, notched Izod impact tests, differential scanning calorimetry, and scanning electronic microscopy. The tensile stress and the impact stress for all samples investigated were found to increase in a nonlinear manner with increasing vibration amplitude and frequency. The tensile stress reached a maximum value at about 8 Hz and 0.15 mm for neat PP and PP filled with 3, 20, and 30 wt% CaCO₃. For PP filled with 40 wt% CaCO₃, the tensile stress reached a maximum value at about 12 Hz and 0.2 mm. The impact stress reached a maximum value at about 12 Hz. From DSC experiments it was shown that the melting temperature slightly increased, but no new polymeric crystalline peak appeared under the vibration force field. The CaCO₃ particles were diffused easily and distributed evenly in the PP melt under the vibration force field, so it is very useful in improving the quality of injection products. Copyright © 2006 Society of Chemical Industry     

Improving the mechanical properties of polypropylene via melt vibration

The effect of melt vibration on the mechanical properties of polypropylene prepared by low-frequency vibration-assisted injection molding (VAIM) has been investigated. With the application of melt vibration technology, the mechanical properties of polypropylene are improved. The yield strength increases with the increment of the vibration frequency, and a peak stands at a special frequency for VAIM; the elongation at break decreases first and then increases with increasing vibration frequency, and a valley stands at a special frequency. The tensile properties increase sharply at an enlarged vibration pressure amplitude with sharply decreased elongation at break. The Young's modulus and impact strength also increase with the vibration frequency and pressure vibration amplitude. When it is prepared at 59.4 MPa and 0.7 Hz, the maximal yield strength is approximately 40 MPa versus 33.7 MPa for a conventional sample; an 18.7% increase in the tensile strength is produced. Self-reinforcing and self-toughening polypropylene molded parts have been found to be prepared at a high vibration frequency or at a large pressure vibration amplitude. Scanning electron micrographs have shown that, in the vibration field, the enhancement of the mechanical properties is attributable to more pronounced spherulite orientation and increased crystallinity in comparison with conventional injection moldings. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

振动参数对HDPE注塑件力学性能的影响

采用自制的振动注射试验装置注射成型高密度聚乙烯(HDPE)制件,探讨振动频率、振动压力幅度对HDPE注塑件屈服强度、断裂伸长率、拉伸弹性模量和冲击强度的影响。结果表明,振动使得注塑件的综合力学性能得到改善;不同温度下振动频率或振动压力幅度对注塑件力学性能的影响程度不同,但其影响趋势是一致的。     

动态塑化过程振动参数对聚丙烯性能的影响

采用新型液压脉振式注射机成型聚丙烯(PP)试样,探讨了塑化过程中振幅和频率对PP物理力学性能和成型过程整机能耗的影响。结果表明:保持其他工艺参数不变,在塑化过程中施加振动后,PP试样的拉伸强度提高9.8%,冲击强度提高13.8%,密度提高0.3%,整机加工能耗降低6.6%。     

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％。